This document proposes a new approach called Comprehensive Long-Run Incremental Cost (LRIC)-Voltage Network Pricing to determine network charges that account for the cost of maintaining nodal voltage levels given network contingencies. The approach links nodal power perturbations to nodal voltage degradation rates and the incremental investment costs required to support voltage levels. It employs the use of nodal voltage spare capacity to gauge the time needed to invest in reactive power compensation devices. The time to invest takes into account network nodal voltage profiles under N-1 circuit contingencies. The approach is demonstrated on the IEEE 14 bus network, showing the difference in charges when considering contingencies compared to the existing power factor penalty approach.
1) The document discusses a long-run incremental cost (LRIC) pricing approach for voltage network charges that aims to reflect future investment costs in reactive power compensation assets needed to maintain voltage profiles within statutory limits under different demand growth rates.
2) It analyzes trends in LRIC voltage network charges on an IEEE 14-bus test system under demand growth rates of 1%, 1.6%, and 2%. Results show charges decrease with higher growth rates.
3) The approach uses spare nodal voltage capacity to provide economically efficient signals reflecting existing network voltage profiles and indicative future costs of reactive power assets. Charges would guide efficient reactive power usage and inform siting of future demand/generation.
As a consequence of sensitive, diverse and complex loads in today's distribution networks, improving power quality in distribution systems has attracted great attention. Power quality issues involve voltage sags, transient interrupts and other distortions in sinusoidal waveforms. Enormous methods have been proposed for power quality modification. One of the methods by which power quality problems might be addressed is to apply power electronic devices in the form of custom power devices. One of such devices is Dynamic Voltage Restorer (DVR) which is connected in series to distribution networks. At the same time, through injection of voltage to the network it is able to control voltage amplitude and phase. It is adopted lend to compensate for voltage sags through injecting series and synchronous three phase voltage. Consisted of three single phase inverters and a DC bus, it can protect susceptible loads against various types of voltage sags as well as other disturbances in the power supply. Moreover, it is capable of generating and absorbing active and reactive power. Therefore, in this paper, different structures of DVR have been investigated and eventually proposed a new structure for DVR based on Γ-Source asymmetric inverter. With the proposed structure, severe voltage sags can be retrieved 80- 90 percent. The simulation results that obtained by using MATLAB/Simulink indicate the properly functioning of proposed structure.
Introducing LQR-fuzzy for a dynamic multi area LFC-DR modelIJECEIAES
It is well known that Load Frequency Control (LFC) model plays a vital role in electric power system design and operation. In the literature, much research works has stated on the advantages and realization of DR (Demand Response), which has proved to be an important part of the future smart grid. In an interconnected power system, if a load demand changes randomly, both frequency and tie line power varies. LFC-DR model is tuned by standard controllers like PI, PD, PID controllers, as they have constant gains. Hence, they are incapable of acquiring desirable dynamic performance for an extensive variety of operating conditions and various load changes. This paper presents the idea of introducing a DR control loop in the traditional Multi area LFC model (called LFC -DR) using LQR- Fuzzy Logic Control. The effect of DR-CDL i.e. (Demand Response Communication Delay Latency) in the design is also considered and is linearized using Padé approximation. Simulation results shows that the addition of DR control loop with proposed controller guarantees stability of the overall closed-loop LFC-DR system which effectively improves the system dynamic performance and is superior over a classical controller at different operating scenarios.
Current matching control system for multi-terminal dc transmission to integra...Jackie Chu
- The document proposes a new control strategy called Current Matching Control (CMC) for multi-terminal HVDC transmission systems used to integrate offshore wind farms.
- CMC matches the current references of the grid-side converters to the wind farm side converters through real-time telecommunications. This allows stable sharing of DC currents between converters.
- The performance of CMC is validated through simulations of a four-terminal MTDC network connecting two offshore wind farms to two mainland grids. Results show CMC can effectively control the system under steady state and transient scenarios.
Regulatory Guidelines to set up Voltage Quality MonitoringLeonardo ENERGY
This session is part of the Clean Energy Regulators Initiative Webinar Programme.
Theme 2 - Pressure Points
Module 2: Voltage Quality Regulation
Voltage quality, sometimes called power quality or technical quality, covers a variety of disturbances in an electrical power system. It is mainly determined by the quality of the voltage waveform and it is an important aspect of the electricity service.
Customers are becoming increasingly sensitive to disturbances in voltage quality. This issue is particularly important taking into account the new regulatory frameworks which put strong emphasis on cost reduction, thereby potentially jeopardizing quality. When setting up a quality regulation framework, there are a number of basic issues that need to be considered first. This understanding is crucial in order to make the right choices in order to arrive at an effective voltage quality regulatory system. It is important to clearly define voltage quality and develop suitable indicators.
This presentation assesses the issue of what regulators need to consider whenever establishing a voltage quality regulatory framework for distribution networks (i.e. up to 35 kV). It presents a general set of guidelines that regulators could consider in introducing and developing voltage quality regulation. Regulation of five important voltage quality dimensions is considered: short-interruptions, voltage dips, flicker, supply voltage variation and harmonic distortion.
IRJET- Review: Different Technology for Distributed Power Flow ControllerIRJET Journal
This document discusses different technologies for distributed power flow controllers (DPFCs). It begins by introducing DPFCs and their advantages over unified power flow controllers. It then describes three different techniques for DPFC controllers: 1) Distributed static series compensators (DSSCs) that use multiple low-power inverters attached to transmission lines, 2) A combined DSSC module approach that reduces components to lower costs, and 3) A proposed single-phase ETO lightweight device-based DPFC that uses optical fiber interfaces to improve reliability at a lower cost. The document reviews these techniques for distributed power flow control.
1) The document presents a control strategy for a grid-interfacing inverter connected to renewable energy sources to improve power quality at the distribution level grid connection point.
2) By controlling the inverter, it can act as both a power converter to inject renewable power into the grid and as an active power filter to compensate for current unbalance, load harmonics, reactive power demand, and neutral current without additional hardware costs.
3) The control strategy aims to maximize utilization of the inverter rating and allows the inverter and nonlinear/unbalanced load at the point of common coupling to appear as a balanced linear load to the grid, maintaining power quality standards.
Design of Low-Voltage Distributed Photovoltaic Systems Oriented to Improve ...IRJET Journal
This document discusses the design of low-voltage distributed photovoltaic (PV) systems to improve their fault ride-through capability. It analyzes the optimal design characteristics for distributed generation PV units connected to low-voltage distribution networks. Specifically, it evaluates how appropriately selecting the equivalent interconnecting reactance of oversized inverters in PV systems can help satisfy low-voltage ride-through requirements at high penetration levels without violating network protections. It also discusses how uniform dispersion of demand for low-voltage ride-through can be achieved along distribution lines. The analysis suggests the derived optimal design approach for PV systems regarding low-voltage ride-through can be applied to any low-voltage distribution network within reasonable constraints.
1) The document discusses a long-run incremental cost (LRIC) pricing approach for voltage network charges that aims to reflect future investment costs in reactive power compensation assets needed to maintain voltage profiles within statutory limits under different demand growth rates.
2) It analyzes trends in LRIC voltage network charges on an IEEE 14-bus test system under demand growth rates of 1%, 1.6%, and 2%. Results show charges decrease with higher growth rates.
3) The approach uses spare nodal voltage capacity to provide economically efficient signals reflecting existing network voltage profiles and indicative future costs of reactive power assets. Charges would guide efficient reactive power usage and inform siting of future demand/generation.
As a consequence of sensitive, diverse and complex loads in today's distribution networks, improving power quality in distribution systems has attracted great attention. Power quality issues involve voltage sags, transient interrupts and other distortions in sinusoidal waveforms. Enormous methods have been proposed for power quality modification. One of the methods by which power quality problems might be addressed is to apply power electronic devices in the form of custom power devices. One of such devices is Dynamic Voltage Restorer (DVR) which is connected in series to distribution networks. At the same time, through injection of voltage to the network it is able to control voltage amplitude and phase. It is adopted lend to compensate for voltage sags through injecting series and synchronous three phase voltage. Consisted of three single phase inverters and a DC bus, it can protect susceptible loads against various types of voltage sags as well as other disturbances in the power supply. Moreover, it is capable of generating and absorbing active and reactive power. Therefore, in this paper, different structures of DVR have been investigated and eventually proposed a new structure for DVR based on Γ-Source asymmetric inverter. With the proposed structure, severe voltage sags can be retrieved 80- 90 percent. The simulation results that obtained by using MATLAB/Simulink indicate the properly functioning of proposed structure.
Introducing LQR-fuzzy for a dynamic multi area LFC-DR modelIJECEIAES
It is well known that Load Frequency Control (LFC) model plays a vital role in electric power system design and operation. In the literature, much research works has stated on the advantages and realization of DR (Demand Response), which has proved to be an important part of the future smart grid. In an interconnected power system, if a load demand changes randomly, both frequency and tie line power varies. LFC-DR model is tuned by standard controllers like PI, PD, PID controllers, as they have constant gains. Hence, they are incapable of acquiring desirable dynamic performance for an extensive variety of operating conditions and various load changes. This paper presents the idea of introducing a DR control loop in the traditional Multi area LFC model (called LFC -DR) using LQR- Fuzzy Logic Control. The effect of DR-CDL i.e. (Demand Response Communication Delay Latency) in the design is also considered and is linearized using Padé approximation. Simulation results shows that the addition of DR control loop with proposed controller guarantees stability of the overall closed-loop LFC-DR system which effectively improves the system dynamic performance and is superior over a classical controller at different operating scenarios.
Current matching control system for multi-terminal dc transmission to integra...Jackie Chu
- The document proposes a new control strategy called Current Matching Control (CMC) for multi-terminal HVDC transmission systems used to integrate offshore wind farms.
- CMC matches the current references of the grid-side converters to the wind farm side converters through real-time telecommunications. This allows stable sharing of DC currents between converters.
- The performance of CMC is validated through simulations of a four-terminal MTDC network connecting two offshore wind farms to two mainland grids. Results show CMC can effectively control the system under steady state and transient scenarios.
Regulatory Guidelines to set up Voltage Quality MonitoringLeonardo ENERGY
This session is part of the Clean Energy Regulators Initiative Webinar Programme.
Theme 2 - Pressure Points
Module 2: Voltage Quality Regulation
Voltage quality, sometimes called power quality or technical quality, covers a variety of disturbances in an electrical power system. It is mainly determined by the quality of the voltage waveform and it is an important aspect of the electricity service.
Customers are becoming increasingly sensitive to disturbances in voltage quality. This issue is particularly important taking into account the new regulatory frameworks which put strong emphasis on cost reduction, thereby potentially jeopardizing quality. When setting up a quality regulation framework, there are a number of basic issues that need to be considered first. This understanding is crucial in order to make the right choices in order to arrive at an effective voltage quality regulatory system. It is important to clearly define voltage quality and develop suitable indicators.
This presentation assesses the issue of what regulators need to consider whenever establishing a voltage quality regulatory framework for distribution networks (i.e. up to 35 kV). It presents a general set of guidelines that regulators could consider in introducing and developing voltage quality regulation. Regulation of five important voltage quality dimensions is considered: short-interruptions, voltage dips, flicker, supply voltage variation and harmonic distortion.
IRJET- Review: Different Technology for Distributed Power Flow ControllerIRJET Journal
This document discusses different technologies for distributed power flow controllers (DPFCs). It begins by introducing DPFCs and their advantages over unified power flow controllers. It then describes three different techniques for DPFC controllers: 1) Distributed static series compensators (DSSCs) that use multiple low-power inverters attached to transmission lines, 2) A combined DSSC module approach that reduces components to lower costs, and 3) A proposed single-phase ETO lightweight device-based DPFC that uses optical fiber interfaces to improve reliability at a lower cost. The document reviews these techniques for distributed power flow control.
1) The document presents a control strategy for a grid-interfacing inverter connected to renewable energy sources to improve power quality at the distribution level grid connection point.
2) By controlling the inverter, it can act as both a power converter to inject renewable power into the grid and as an active power filter to compensate for current unbalance, load harmonics, reactive power demand, and neutral current without additional hardware costs.
3) The control strategy aims to maximize utilization of the inverter rating and allows the inverter and nonlinear/unbalanced load at the point of common coupling to appear as a balanced linear load to the grid, maintaining power quality standards.
Design of Low-Voltage Distributed Photovoltaic Systems Oriented to Improve ...IRJET Journal
This document discusses the design of low-voltage distributed photovoltaic (PV) systems to improve their fault ride-through capability. It analyzes the optimal design characteristics for distributed generation PV units connected to low-voltage distribution networks. Specifically, it evaluates how appropriately selecting the equivalent interconnecting reactance of oversized inverters in PV systems can help satisfy low-voltage ride-through requirements at high penetration levels without violating network protections. It also discusses how uniform dispersion of demand for low-voltage ride-through can be achieved along distribution lines. The analysis suggests the derived optimal design approach for PV systems regarding low-voltage ride-through can be applied to any low-voltage distribution network within reasonable constraints.
Simulation of DVR by using Ultra Capacitor to Analysis of THD with and withou...IRJET Journal
This document presents a simulation of a Dynamic Voltage Restorer (DVR) using an Ultracapacitor for energy storage. It compares the total harmonic distortion (THD) for voltage sags and swells when the Ultracapacitor is connected to the inverter with and without a DC-DC converter. The DVR protects sensitive loads from power quality issues like voltage sags and swells. Ultracapacitors are suitable for this application due to their high power density and ability to provide rapid bursts of power. Simulation results show that connecting the Ultracapacitor to the inverter via a DC-DC converter can improve the THD during compensation compared to directly connecting it without a converter.
This document summarizes a paper that proposes a Green Power Zone (GPZ) concept to provide high quality electrical power. A GPZ would use custom power devices like a DVR, DSTATCOM, and UPQC to regulate voltage and power quality. It would receive power from two independent substations through solid state transfer switches to improve reliability. The GPZ center would monitor power quality and control devices to maintain a stable voltage supply closer to ideal levels, despite faults or interruptions from utilities. Simulation results demonstrated the GPZ's ability to compensate for issues like sags, swells, harmonics and imbalance.
This document presents a framework for simultaneously mapping multiple applications to an MPSoC chip while accounting for process variations to maximize yield. The framework assigns voltages to cores and forms voltage islands to minimize delay variations. It then maps applications to tiles and routes communication while satisfying power and timing constraints. Simulated annealing is used to iteratively perturb the core mapping, application mapping, and voltages to improve power yield and average core delay. Implementation in C++ shows the approach increases power yield from 891 to 906 under a 105W constraint.
Smart Power Transmission System Using FACTS DeviceIJAPEJOURNAL
Making of smart grids puts mounting pressure on the nation’s aging electric power transmission system. Just planting additional towers and stringing more line won’t practice the nation’s electric power transmission infrastructure to meet up the energy challenges ahead. Smart grids stand geared up to play a much larger role in the energy equation for reduction of transmission line losses. The FACTS controllers come out with the capability of enhancing transmission system control, reliability, and operation. This paper will discuss and express how Static Synchronous Compensator (STATCOM) has effectively been applied to power system for efficiently regulating system voltage and thus increase system load ability. This paper investigates the effects of (STATCOM) on voltage stability of a power system at different positions.The simulation analysis of this paper can be used as guideline for power industry. The study is thereby simulated using the MATLAB/SIMULINK software and simulation results show that STATCOM is effective in midpoint voltage regulation on transmission line. In this paper comparison is also performed between STATCOM and SVC under fault condition and it is proved that STATCOM have the capacity to provide more capacitive power for the period of a fault than SVC.
Simulation of DVR for power Quality Improvement by using Ultra CapacitorIRJET Journal
This document discusses using an ultracapacitor (UCAP) integrated with a dynamic voltage restorer (DVR) to improve power quality by mitigating voltage sags and swells. A DVR injects voltage in series to compensate for disturbances, but has limited real power capability. UCAP provides high power density for short durations, making it suitable for combining with DVR. The document presents a simulation model of an integrated UCAP-DVR system in MATLAB. Results show the DVR maintains constant load voltage during faults by injecting compensating voltage supplied by the UCAP, demonstrating the system's ability to effectively mitigate voltage quality issues.
Impact of Positive Sequence Admittance and Negative Sequence Conductance of D...ijtsrd
Voltage fluctuations resulting from variable output power of renewable energy sources are strictly challenging power quality in distributed-generation systems. This paper presents a control method for distributed static synchronous compensator (D-STATCOM) to alleviate variation of both positive- and negative-sequence voltages. The D-STATCOM simultaneously operates as fundamental positive-sequence admittance and fundamental negative-sequence conductance to restore the positive sequence voltage to the nominal value as well as reduce the negative-sequence voltage to an allowable level. Both admittance and conductance are dynamically tuned to improve voltage regulation performances in response to load changes and power variation of renewable sources. A proportional“resonant current regulator with selectively harmonic compensation is realized to control the fundamental current of the D-STATCOM as well as reduce the harmonic current, which could be an advantage in practical applications due to high voltage distortion in low-voltage micro grids. Voltage-regulation performances are discussed for different D-STATCOM locations as well as different D-STATCOM currents. Computer simulations and laboratory tests validate effectiveness. CH. Venkata Krishna | N. S. Kalyan Chakravarthi"Impact of Positive Sequence Admittance and Negative Sequence Conductance of D-Statcom to Compensate Variations in Voltage Levels in Distributed Generation Systems" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-1 , December 2017, URL: http://www.ijtsrd.com/papers/ijtsrd5919.pdf http://www.ijtsrd.com/engineering/electrical-engineering/5919/impact-of-positive-sequence-admittance-and-negative-sequence-conductance-of-d-statcom-to-compensate-variations-in-voltage-levels-in-distributed-generation-systems/ch-venkata-krishna
A Modern Technique of Deduction in Leakage Current in Resonant Bi-directional...IJMTST Journal
This Paper Presents A whole New resonant twin active bridge(DAB) topology, that uses a tuned inductor-capacitor-inductor(LCL) network. As compared to ancient DAB topologies, the planned topologies significantly reduced the bridge current, lowering every physical phenomenon and alter losses and conjointly VA rating associated with the bridges. The performance of the DAB is investigated using a mathematical model at a lower place varied operational conditions. Experiment results of a model is reduced the outflow current of the circuit. are presented with discussion to demonstrate the improved performance of the LCL DAB topology. Result clearly that the planned DAB Topology provide higher efficiency over an oversized vary of every input voltage and as compared to ancient DAB topology
IRJET - Review Paper on RSC-MLC Base Smart PV-DSTATCOM for Multi Objective Pu...IRJET Journal
This document summarizes research on using a Real Switch Count Multi-Level Converter (RSC-MLC) based smart PV-DSTATCOM for multiple objectives including improving power quality, compensating reactive power flow, and optimizing the DC link voltage. A DSTATCOM uses a voltage source converter to inject current and control reactive power flow. The proposed method uses an RSC-MLC to regulate the DC link voltage from a PV source, reducing voltage stress on switches and minimizing losses. It can supply solar power to loads and compensate reactive power with battery support when solar power is unavailable. The document reviews related work on DSTATCOM control and applications and provides details on controlling the proposed RSC-MLC based PV-
Dynamic Voltage Conditioner, a New Concept for Smart Low-Voltage Distribution...Asoka Technologies
Power Quality (PQ) improvement in distribution level is an increasing concern in modern electrical power systems. One of the main problems in LV networks is related to load voltage stabilization close to the nominal value. Usually this problem is solved by Smart Distribution Transformers, Hybrid Transformers and Solid-state Transformers, but also Dynamic Voltage Conditioner (DVC) can be an innovative and a cost effective solution. The paper introduces a new control method of a single-phase DVC system able to compensate these long duration voltage drifts. For these events, it is mandatory to avoid active power exchanges so, the controller is designed to work with non-active power only. Operation limits for quadrature voltage injection control is formulated and reference voltage update procedure is proposed to guarantee its continuous operating. DVC performance for main voltage and load variation is examined. Proposed solution is validated with simulation study and experimental laboratory tests. Some simulation and experimental results are illustrated to show the prototype device’s performance.
The document discusses techniques for optimal placement of distributed generation (DG) in distribution networks based on voltage stability. It presents modal analysis and continuous power flow methods to evaluate voltage stability and determine the best DG locations. As a case study, these techniques are applied to a 33-bus radial distribution network with 40% DG penetration to minimize losses and improve voltage profiles. Additionally, a reactive power ranking method provides a priority list of DG sites to compensate for reactive power shortages. The techniques ensure DG placement enhances voltage security margin while addressing both long-term and short-term reactive power issues.
The paper highlights the need for an Active System Management (ASM) of distribution networks as a key tool for the efficient and secure integration of a high share of Distributed Energy Resources (DER). The paper provides technical and regulatory recommendations that mainly focus on distributed generation but are also largely applicable to flexible loads, electric vehicles and storage.
This document analyzes the optimal positioning of superconducting fault current limiters (SFCLs) in smart grids. It simulates different fault scenarios in a model smart grid containing distributed generation from wind farms. It finds that installing an SFCL at the substation or distribution network increases fault current from wind farms. The best performance is achieved by installing a single SFCL at the point of integration between the wind farm and the grid. This location limits fault current from both the wind farm and the main power system effectively without negative impacts. The analysis suggests strategic placement of SFCLs at integration points is most efficient for protecting multiple distributed resources in smart grids.
A Review on Hybrid Active Power Filter for Power Quality Improvement IRJET Journal
This document provides a review of hybrid active power filters for improving power quality. It discusses how power quality issues like harmonics, voltage sag, and swell have increased with more nonlinear loads. Passive filters were commonly used but have limitations. Hybrid active power filters combine active and passive filters to overcome limitations. It provides benefits like compensating for harmonics, reactive power compensation, and improving voltage quality while reducing the cost and rating of active filters. The paper reviews hybrid active power filter configurations, components, control methods and provides an overview of their use in improving power system quality.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Minimization of Overall Losses of a Distribution System under Contingency Con...paperpublications3
Abstract: In this paper, a methodology has been proposed to minimize the losses of distribution systems (technical and non-technical losses) that is an absolutely necessary objective in the sound management of any electrical utility. The transmission & distribution losses in Indian power system are high. Most of the efforts of power planners concentrate on augmenting supply by building new power plants. But saving is possible by improving operating conditions for the distribution network. Due to inadequate planning and methods adopted for load shifting, some networks are under loaded while others are overloaded. Thus there is some scope for improvement in operating strategies. Network reconfiguration in distribution system is realized by changing the status of the sectionalizing switches and is usually done for loss reduction and avoids overloading. In primary distribution system (11KV), the need for reconfiguration occurs in emergency condition following the fault to isolate faulted section and in normal condition to reduce system losses or to avoid overloading of network. The main objective of the paper is to outline a methodology for management of distribution system for loss reduction by network reconfiguration. The possible techniques used for power loss reduction, which are network reconfiguration and capacitor addition. Case studies were simulated on an interconnected ring main distribution network.
IRJET- Improved Electrical Power Supply to Trans-Amadi Industrial Layout, Por...IRJET Journal
This document presents an analysis of improving the electrical power supply to the Trans-Amadi Industrial Layout in Port Harcourt, Nigeria. The analysis models and simulates the existing 33kV network using ETAP software. It finds that some transformers are overloaded while others are underloaded. It is concluded that the system needs improvements. Recommendations include adding transformers to overloaded feeders, upgrading some transformers to higher capacities, replacing some transformers with lower capacities, and installing capacitor banks to improve the power factor.
A mho type phase comparator relay guideline using phase comparison technique ...IJECEIAES
This paper presents a mho distance relay simulation based on the phase comparison technique using a typical electrical power systems analysis software for two cases: when the operation state is close to the static voltage limit and during a dynamic perturbation in the system. The paper evaluates the impedance variations caused by complex voltage values, the mho polarization, and the comparator operating region into the complex plane. In addition, the paper found the information for the dynamic perturbations from the outputs considering a mid-term stability program. The simulation of the mho-phase comparator in the static voltage proximity limit detects unit distance elements with impedance measured close to reach the threshold in the steady-state. Dynamic mho simulations in the complex plane are successfully tested by plotting time phase difference curves on the comparator input signals. Relay programmers can use these curves to analyze other phase comparators applications and the corresponding models in the complex plane.
This document discusses generalized closed sets in topological spaces. It begins by introducing several types of generalized closed sets that have been defined in previous literature, such as g-closed sets, sg-closed sets, gs-closed sets, etc. It then defines a new type of generalized closed set called a g*s-closed set, which is a subset A such that the semi-closure of A is contained in every g-open set containing A. Examples are provided to illustrate g*s-closed sets. Properties of g*s-closed sets are discussed, such as every semi-closed set being g*s-closed, but the converse is not true. The relationship between g*s-closed sets and other
Experimental Investigation of Performance & Emission Characteristics of Diese...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
The document describes a training approach for European women in developing digital skills. It analyzes key considerations in designing the training, including the needs of adult female learners and desired learning objectives. The approach uses mastery learning and direct instruction models. Trainees will develop basic computer skills and cultural awareness through interactive online materials and activities. Trainers will guide trainees and evaluate their progress, while trainees will participate in groups, exchange views, and provide feedback on the training approach.
Variant High Origin of the Posterior Tibial ArteryIJMER
1. The document describes an anatomical variation observed during a routine cadaver dissection where the posterior tibial artery originated from the popliteal artery proximal to the popliteus muscle.
2. This variation is important for orthopaedic surgeons, radiologists, and others to be aware of to minimize risks during knee surgeries and angiographic studies.
3. The authors conclude that variations in the branching pattern of the popliteal artery are common and need to be considered during related surgical and medical interventions.
Seismic Behavior of Two Layers of Drum And Up To the Mouth of the Mouth Dept...IJMER
This document summarizes a study on the seismic behavior of two-layer drum structures with varying deflection to span ratios and depths to the mouth. Finite element analysis was conducted using ANSYS software to analyze models with different geometric properties under dead and live loads as well as earthquake loads. Modal analysis was performed to determine natural frequencies and period. Dynamic time history analysis found that increasing the depth to the mouth increases the period of the structure. Buckling behavior was also investigated, with some models experiencing buckling of members during seismic loading. The study provides data on the steel weights, natural frequencies, displacements, and buckling of members for different drum structure configurations.
Simulation of DVR by using Ultra Capacitor to Analysis of THD with and withou...IRJET Journal
This document presents a simulation of a Dynamic Voltage Restorer (DVR) using an Ultracapacitor for energy storage. It compares the total harmonic distortion (THD) for voltage sags and swells when the Ultracapacitor is connected to the inverter with and without a DC-DC converter. The DVR protects sensitive loads from power quality issues like voltage sags and swells. Ultracapacitors are suitable for this application due to their high power density and ability to provide rapid bursts of power. Simulation results show that connecting the Ultracapacitor to the inverter via a DC-DC converter can improve the THD during compensation compared to directly connecting it without a converter.
This document summarizes a paper that proposes a Green Power Zone (GPZ) concept to provide high quality electrical power. A GPZ would use custom power devices like a DVR, DSTATCOM, and UPQC to regulate voltage and power quality. It would receive power from two independent substations through solid state transfer switches to improve reliability. The GPZ center would monitor power quality and control devices to maintain a stable voltage supply closer to ideal levels, despite faults or interruptions from utilities. Simulation results demonstrated the GPZ's ability to compensate for issues like sags, swells, harmonics and imbalance.
This document presents a framework for simultaneously mapping multiple applications to an MPSoC chip while accounting for process variations to maximize yield. The framework assigns voltages to cores and forms voltage islands to minimize delay variations. It then maps applications to tiles and routes communication while satisfying power and timing constraints. Simulated annealing is used to iteratively perturb the core mapping, application mapping, and voltages to improve power yield and average core delay. Implementation in C++ shows the approach increases power yield from 891 to 906 under a 105W constraint.
Smart Power Transmission System Using FACTS DeviceIJAPEJOURNAL
Making of smart grids puts mounting pressure on the nation’s aging electric power transmission system. Just planting additional towers and stringing more line won’t practice the nation’s electric power transmission infrastructure to meet up the energy challenges ahead. Smart grids stand geared up to play a much larger role in the energy equation for reduction of transmission line losses. The FACTS controllers come out with the capability of enhancing transmission system control, reliability, and operation. This paper will discuss and express how Static Synchronous Compensator (STATCOM) has effectively been applied to power system for efficiently regulating system voltage and thus increase system load ability. This paper investigates the effects of (STATCOM) on voltage stability of a power system at different positions.The simulation analysis of this paper can be used as guideline for power industry. The study is thereby simulated using the MATLAB/SIMULINK software and simulation results show that STATCOM is effective in midpoint voltage regulation on transmission line. In this paper comparison is also performed between STATCOM and SVC under fault condition and it is proved that STATCOM have the capacity to provide more capacitive power for the period of a fault than SVC.
Simulation of DVR for power Quality Improvement by using Ultra CapacitorIRJET Journal
This document discusses using an ultracapacitor (UCAP) integrated with a dynamic voltage restorer (DVR) to improve power quality by mitigating voltage sags and swells. A DVR injects voltage in series to compensate for disturbances, but has limited real power capability. UCAP provides high power density for short durations, making it suitable for combining with DVR. The document presents a simulation model of an integrated UCAP-DVR system in MATLAB. Results show the DVR maintains constant load voltage during faults by injecting compensating voltage supplied by the UCAP, demonstrating the system's ability to effectively mitigate voltage quality issues.
Impact of Positive Sequence Admittance and Negative Sequence Conductance of D...ijtsrd
Voltage fluctuations resulting from variable output power of renewable energy sources are strictly challenging power quality in distributed-generation systems. This paper presents a control method for distributed static synchronous compensator (D-STATCOM) to alleviate variation of both positive- and negative-sequence voltages. The D-STATCOM simultaneously operates as fundamental positive-sequence admittance and fundamental negative-sequence conductance to restore the positive sequence voltage to the nominal value as well as reduce the negative-sequence voltage to an allowable level. Both admittance and conductance are dynamically tuned to improve voltage regulation performances in response to load changes and power variation of renewable sources. A proportional“resonant current regulator with selectively harmonic compensation is realized to control the fundamental current of the D-STATCOM as well as reduce the harmonic current, which could be an advantage in practical applications due to high voltage distortion in low-voltage micro grids. Voltage-regulation performances are discussed for different D-STATCOM locations as well as different D-STATCOM currents. Computer simulations and laboratory tests validate effectiveness. CH. Venkata Krishna | N. S. Kalyan Chakravarthi"Impact of Positive Sequence Admittance and Negative Sequence Conductance of D-Statcom to Compensate Variations in Voltage Levels in Distributed Generation Systems" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-1 , December 2017, URL: http://www.ijtsrd.com/papers/ijtsrd5919.pdf http://www.ijtsrd.com/engineering/electrical-engineering/5919/impact-of-positive-sequence-admittance-and-negative-sequence-conductance-of-d-statcom-to-compensate-variations-in-voltage-levels-in-distributed-generation-systems/ch-venkata-krishna
A Modern Technique of Deduction in Leakage Current in Resonant Bi-directional...IJMTST Journal
This Paper Presents A whole New resonant twin active bridge(DAB) topology, that uses a tuned inductor-capacitor-inductor(LCL) network. As compared to ancient DAB topologies, the planned topologies significantly reduced the bridge current, lowering every physical phenomenon and alter losses and conjointly VA rating associated with the bridges. The performance of the DAB is investigated using a mathematical model at a lower place varied operational conditions. Experiment results of a model is reduced the outflow current of the circuit. are presented with discussion to demonstrate the improved performance of the LCL DAB topology. Result clearly that the planned DAB Topology provide higher efficiency over an oversized vary of every input voltage and as compared to ancient DAB topology
IRJET - Review Paper on RSC-MLC Base Smart PV-DSTATCOM for Multi Objective Pu...IRJET Journal
This document summarizes research on using a Real Switch Count Multi-Level Converter (RSC-MLC) based smart PV-DSTATCOM for multiple objectives including improving power quality, compensating reactive power flow, and optimizing the DC link voltage. A DSTATCOM uses a voltage source converter to inject current and control reactive power flow. The proposed method uses an RSC-MLC to regulate the DC link voltage from a PV source, reducing voltage stress on switches and minimizing losses. It can supply solar power to loads and compensate reactive power with battery support when solar power is unavailable. The document reviews related work on DSTATCOM control and applications and provides details on controlling the proposed RSC-MLC based PV-
Dynamic Voltage Conditioner, a New Concept for Smart Low-Voltage Distribution...Asoka Technologies
Power Quality (PQ) improvement in distribution level is an increasing concern in modern electrical power systems. One of the main problems in LV networks is related to load voltage stabilization close to the nominal value. Usually this problem is solved by Smart Distribution Transformers, Hybrid Transformers and Solid-state Transformers, but also Dynamic Voltage Conditioner (DVC) can be an innovative and a cost effective solution. The paper introduces a new control method of a single-phase DVC system able to compensate these long duration voltage drifts. For these events, it is mandatory to avoid active power exchanges so, the controller is designed to work with non-active power only. Operation limits for quadrature voltage injection control is formulated and reference voltage update procedure is proposed to guarantee its continuous operating. DVC performance for main voltage and load variation is examined. Proposed solution is validated with simulation study and experimental laboratory tests. Some simulation and experimental results are illustrated to show the prototype device’s performance.
The document discusses techniques for optimal placement of distributed generation (DG) in distribution networks based on voltage stability. It presents modal analysis and continuous power flow methods to evaluate voltage stability and determine the best DG locations. As a case study, these techniques are applied to a 33-bus radial distribution network with 40% DG penetration to minimize losses and improve voltage profiles. Additionally, a reactive power ranking method provides a priority list of DG sites to compensate for reactive power shortages. The techniques ensure DG placement enhances voltage security margin while addressing both long-term and short-term reactive power issues.
The paper highlights the need for an Active System Management (ASM) of distribution networks as a key tool for the efficient and secure integration of a high share of Distributed Energy Resources (DER). The paper provides technical and regulatory recommendations that mainly focus on distributed generation but are also largely applicable to flexible loads, electric vehicles and storage.
This document analyzes the optimal positioning of superconducting fault current limiters (SFCLs) in smart grids. It simulates different fault scenarios in a model smart grid containing distributed generation from wind farms. It finds that installing an SFCL at the substation or distribution network increases fault current from wind farms. The best performance is achieved by installing a single SFCL at the point of integration between the wind farm and the grid. This location limits fault current from both the wind farm and the main power system effectively without negative impacts. The analysis suggests strategic placement of SFCLs at integration points is most efficient for protecting multiple distributed resources in smart grids.
A Review on Hybrid Active Power Filter for Power Quality Improvement IRJET Journal
This document provides a review of hybrid active power filters for improving power quality. It discusses how power quality issues like harmonics, voltage sag, and swell have increased with more nonlinear loads. Passive filters were commonly used but have limitations. Hybrid active power filters combine active and passive filters to overcome limitations. It provides benefits like compensating for harmonics, reactive power compensation, and improving voltage quality while reducing the cost and rating of active filters. The paper reviews hybrid active power filter configurations, components, control methods and provides an overview of their use in improving power system quality.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Minimization of Overall Losses of a Distribution System under Contingency Con...paperpublications3
Abstract: In this paper, a methodology has been proposed to minimize the losses of distribution systems (technical and non-technical losses) that is an absolutely necessary objective in the sound management of any electrical utility. The transmission & distribution losses in Indian power system are high. Most of the efforts of power planners concentrate on augmenting supply by building new power plants. But saving is possible by improving operating conditions for the distribution network. Due to inadequate planning and methods adopted for load shifting, some networks are under loaded while others are overloaded. Thus there is some scope for improvement in operating strategies. Network reconfiguration in distribution system is realized by changing the status of the sectionalizing switches and is usually done for loss reduction and avoids overloading. In primary distribution system (11KV), the need for reconfiguration occurs in emergency condition following the fault to isolate faulted section and in normal condition to reduce system losses or to avoid overloading of network. The main objective of the paper is to outline a methodology for management of distribution system for loss reduction by network reconfiguration. The possible techniques used for power loss reduction, which are network reconfiguration and capacitor addition. Case studies were simulated on an interconnected ring main distribution network.
IRJET- Improved Electrical Power Supply to Trans-Amadi Industrial Layout, Por...IRJET Journal
This document presents an analysis of improving the electrical power supply to the Trans-Amadi Industrial Layout in Port Harcourt, Nigeria. The analysis models and simulates the existing 33kV network using ETAP software. It finds that some transformers are overloaded while others are underloaded. It is concluded that the system needs improvements. Recommendations include adding transformers to overloaded feeders, upgrading some transformers to higher capacities, replacing some transformers with lower capacities, and installing capacitor banks to improve the power factor.
A mho type phase comparator relay guideline using phase comparison technique ...IJECEIAES
This paper presents a mho distance relay simulation based on the phase comparison technique using a typical electrical power systems analysis software for two cases: when the operation state is close to the static voltage limit and during a dynamic perturbation in the system. The paper evaluates the impedance variations caused by complex voltage values, the mho polarization, and the comparator operating region into the complex plane. In addition, the paper found the information for the dynamic perturbations from the outputs considering a mid-term stability program. The simulation of the mho-phase comparator in the static voltage proximity limit detects unit distance elements with impedance measured close to reach the threshold in the steady-state. Dynamic mho simulations in the complex plane are successfully tested by plotting time phase difference curves on the comparator input signals. Relay programmers can use these curves to analyze other phase comparators applications and the corresponding models in the complex plane.
This document discusses generalized closed sets in topological spaces. It begins by introducing several types of generalized closed sets that have been defined in previous literature, such as g-closed sets, sg-closed sets, gs-closed sets, etc. It then defines a new type of generalized closed set called a g*s-closed set, which is a subset A such that the semi-closure of A is contained in every g-open set containing A. Examples are provided to illustrate g*s-closed sets. Properties of g*s-closed sets are discussed, such as every semi-closed set being g*s-closed, but the converse is not true. The relationship between g*s-closed sets and other
Experimental Investigation of Performance & Emission Characteristics of Diese...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
The document describes a training approach for European women in developing digital skills. It analyzes key considerations in designing the training, including the needs of adult female learners and desired learning objectives. The approach uses mastery learning and direct instruction models. Trainees will develop basic computer skills and cultural awareness through interactive online materials and activities. Trainers will guide trainees and evaluate their progress, while trainees will participate in groups, exchange views, and provide feedback on the training approach.
Variant High Origin of the Posterior Tibial ArteryIJMER
1. The document describes an anatomical variation observed during a routine cadaver dissection where the posterior tibial artery originated from the popliteal artery proximal to the popliteus muscle.
2. This variation is important for orthopaedic surgeons, radiologists, and others to be aware of to minimize risks during knee surgeries and angiographic studies.
3. The authors conclude that variations in the branching pattern of the popliteal artery are common and need to be considered during related surgical and medical interventions.
Seismic Behavior of Two Layers of Drum And Up To the Mouth of the Mouth Dept...IJMER
This document summarizes a study on the seismic behavior of two-layer drum structures with varying deflection to span ratios and depths to the mouth. Finite element analysis was conducted using ANSYS software to analyze models with different geometric properties under dead and live loads as well as earthquake loads. Modal analysis was performed to determine natural frequencies and period. Dynamic time history analysis found that increasing the depth to the mouth increases the period of the structure. Buckling behavior was also investigated, with some models experiencing buckling of members during seismic loading. The study provides data on the steel weights, natural frequencies, displacements, and buckling of members for different drum structure configurations.
This document discusses the different types of diabetes, including Type 1, Type 2, and gestational diabetes. It covers the symptoms, causes, treatment options, and management of diabetes through diet, exercise, and medication. The key points are that there are different types of diabetes, symptoms can include frequent urination and thirst, and treatment involves monitoring blood sugar levels through diet, exercise, and insulin or other medication.
Numerical Analysis of Fin Side Turbulent Flow for Round and Flat Tube Heat E...IJMER
Numerical three dimensional simulation of turbulent flow in round and flat tube fin heat exchangers having two rows of staggered arrangement has been carried out to investigate fluid flow and heat transfer characteristics using ANSYS Fluent 14® software. HYPERMESH10® Software has been
used for the creation of models as well for meshing. The cases have been simulated for different fin side Reynolds number in turbulent regime to observe the effect of various parameters like fin pitch, tube pitch and fin temperature on Colburn j factor and Friction factor f for both round and flat tubes. Fin side flow has been simulated using various steady flow models in the software for same velocity range. As simulation using k-ε model resulted in close agreement with that of experimental in turbulent regime, it is considered for further analysis. The performance of round tubes is compared with that of flat tubes with same flow area and geometrical parameters. For both round and flat tube domains with all the geometrical configurations simulated in this work Colburn j factor varied inversely with the inlet air velocity. The heat transfer is more with the higher fin spacing for both round and flat tubes following the above said trend. On the other hand, the pressure drop across the tubes is more with the lesser fin spacing
in contrast to the heat transfer. Due to lesser turbulent intensity in flat tubes, they exhibit slightly lesser
Colburn j factor and considerably lesser pressure drop compared to round tubes. Although flat tubes
exhibit slightly lesser Colburn j factor, due to larger exposed tube area increase in the air temperature in
the fin side is comparable with that of round tubes. Higher fin temperatures result with lesser Colburn j factor and higher pressure drop across the tubes although the fin temperature affects the pressure drop to lesser extent.
An Eavesdropping Model for Securing Communications over Wireless Broadcast Ne...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Detection of Duplicate Address in Mobile Adhoc Networks for On Demand Routing...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
A production - Inventory model with JIT setup cost incorporating inflation an...IJMER
A production inventory model with Just-In-Time (JIT) set-up cost has been developed in which inflation and time value of money are considered under an imperfect production process. The demand rate is considered to be a function of advertisement cost and selling price. Unit production cost is considered incorporating several features like energy and labour cost, raw material cost and development cost of the manufacturing system. Development cost is assumed to be a function of reliability parameter.
Considering these phenomena, an analytic expression is obtained for the total profit of the model. The model provides an analytical solution to maximize the total profit function.A numerical example is presented to illustrate the model along with graphical analysis. Sensitivity analysis has been carried out to identify the most sensitive parameters of the model.
An Amalgamation-Based System for Micro aneurysm Detection and Diabetic Retino...IJMER
We propose an ensemble-based framework to improve microaneurysm detection. Unlike
the well-known approach of considering the output of multiple classifiers, we propose a combination of
internal components of microaneurysm detectors, namely preprocessing methods and candidate
extractors. We have evaluated our approach for microaneurysm detection in an online competition,
where this algorithm is currently ranked as first, and also on two other databases.
Numerical Analysis of Header Configuration of the Plate-Fin Heat ExchangerIJMER
Numerical analysis of a plate fin heat exchanger accounting for the effect of fluid flow
maldistribution onthe inlet header configuration of the heat exchanger is investigated. In this analysis , it
was found that flow maldistribution has effect on the flow perpendicular to its velocity direction. The peak
velocity occurs in the central zone of the header while the velocityalong the perpendicular direction of the
inlet flow diminishes more and more. By this investigation,the results of the flow maldistribution are
presented for a plate fin heat exchangerwhich is reduced as compare to theexisting configuration of the
plate fin heat exchanger.
This document presents guidelines for choosing process parameters to efficiently operate a nutrient mist reactor for growing hairy roots with intermittent mist-ON/OFF cycles. It describes a theoretical model that simulates the evolution of liquid holdup and concentration in the root bed. The model shows that the reactor can be run with very low cumulative mist-ON duration (e.g. 10% of total time) while keeping mist-OFF for most of the time (e.g. 90%), to prevent nutrient deficiency or waterlogging. The optimal durations of mist-ON and mist-OFF cycles depend on parameters like feed concentration, flow rate, and drainage rate. The guidelines can help efficiently design and operate nutrient mist reactors for hairy root cultivation.
The document summarizes the European Women Interactive Learning (EWIL) project. The EWIL project aims to stimulate women's motivation to learn and raise the quality of education opportunities for women in non-formal contexts. Specifically, the project aims to allow women to acquire ICT knowledge, promote women's participation in adult learning using culturally relevant content, and help women maximize their ICT skills for personal and professional use. The project receives funding from the Lifelong Learning Programme of the European Union.
This document describes enhancements made to the energy modeling framework in the OMNET++ wireless sensor network simulator. OMNET++ is a modular discrete event simulator written in C++ that allows models to be built from reusable components. The document discusses several frameworks within OMNET++ for modeling energy consumption, including MIXIM, INET, INETMANET, PAWIS, and CASTALIA. It provides details on how energy parameters can be configured in simulation profiles, how energy levels are updated during transmissions and other events, and how output is recorded to analyze energy performance.
This document summarizes a study on the finite element analysis and design of experiments of a parabolic leaf spring for a mini loader truck. The leaf spring was modeled in CATIA V5 and analyzed for maximum von Mises stress and displacement. Design of experiments was conducted by varying the camber and eye distance. The results showed that increasing camber decreases displacement while increasing stress, and increasing eye distance increases both displacement and stress. The optimum leaf spring dimensions can be determined from the design of experiments analysis.
A Novel Information Accountability Framework for Cloud ComputingIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
On ranges and null spaces of a special type of operator named 𝝀 − 𝒋𝒆𝒄𝒕𝒊𝒐𝒏. – ...IJMER
This document discusses λ-jections, a generalization of projection operators. It shows that if E is a λ-jection, then expressions of the form aE^2 + bE are projections under certain conditions on a and b. Three specific projections - A, B, and C - are obtained. It is shown that A and B are orthogonal, and that the range and null space of E are equal to those of C. The ranges of A and B are also characterized in terms of the operator E.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
1. The document discusses a long-run incremental cost (LRIC) pricing approach called LRIC-voltage network charging that aims to reflect the future investment costs of maintaining voltage profiles on electricity networks.
2. The LRIC-voltage charges are calculated based on the spare capacity or "headroom" of nodal voltages on the network and how injections or withdrawals of reactive power at nodes could advance or defer future investments in reactive power compensation assets.
3. The paper analyzes how the LRIC-voltage network charges would vary under different assumed rates of demand growth (1%, 1.6%, and 2%), providing insights into how the charges could change under different demand scenarios over time.
Enhancement of Reactive Power Compensation in PV Grid System To Increase The ...IJSRD
This project existing models force limits on the allowable feeder voltage variety in a disseminate environment. These stipulations must be regarded by the disseminated power generators (suppliers), which put a top on the entrance level. This project proposes a novel plan, where an assistant circuit (including an inverter and responsive force bank, RPB), in conjunction with a PV-lattice framework, builds the framework’s receptive force pay limit up to 300% contrasted with the first or devoted VAR limit of the primary PV inverter. In resentment of utilizing just the routine discrete type of capaci-tor/inductor bank, the whole VAR reach can be controlled.
This article proposes a technique for verifying power and ground grids under general and hierarchical constraints. It models the power and ground grids together using an RC circuit model. In contrast to previous work that assumed symmetry between the grids, the proposed approach explicitly models potential asymmetry. It formulates the verification problem as computing worst-case voltage fluctuations given constraints on current drawn by circuit blocks connected to the grids. Tight lower and upper bounds on voltage fluctuations are obtained by solving linear programs. Experimental results show errors within a few millivolts. The technique also efficiently solves the hierarchical constraint case using sorting and deletion.
A Novel Approach for Allocation of Optimal Capacitor and Distributed Generati...paperpublications3
This document presents two algorithms for optimally allocating capacitors and distributed generation on radial distribution systems. The algorithms predict reactive power and real power requirements that can be supplied by capacitor banks and distributed generation units. This arrangement reduces transmission losses and improves voltage stability. The algorithms were implemented on the IEEE 69-node and 52-node test systems. Load flow analysis was performed using a forward/backward sweep method to calculate node voltages, branch currents, and power losses. The results show reductions in losses and improvements to voltage profiles with the addition of capacitors and distributed generation.
This document summarizes a research paper that proposes using distributed control of multiple energy storage units (ESUs) to manage voltage and loading in electric distribution networks with renewable energy sources like solar and wind. The distributed control approach coordinates the ESUs to store excess power generated during peak periods and discharge it during peak load periods. Each ESU can provide both active and reactive power to support voltage and manage power flows. The distributed control strategy uses a consensus algorithm to divide the required active power reduction equally among ESUs based on their available capacity. Simulation results are presented to analyze the coordinated control of ESU active and reactive power outputs over time.
Non-uniform Rooftop PVs Distribution Effect to Improve Voltage Profile in Res...TELKOMNIKA JOURNAL
This paper presents the simple design of a grid-tied single-phase with distributed rooftop
photovoltaic (PV) non-uniformly location and ratings. All the inclusion components in the developed
scheme are estimated and defined as the inevitability of low voltage (LV) residential network. This
developed scheme is purposed for allocating AC and DC load, which are divided into four steps: the sized
determination of PV inverter (1-5kW), the selection of PV array, the size determination of battery and the
selection of other supporting components. The purposed configuration consists of modeling the system
with non-uniform distributions of rooftop PVs, modeling the rooftop PVs based on their injected active and
reactive power, and finally the inclusion of battery storage, based on its state of charge (SOC). Due to test
the configuration, several cases are built in the MATLAB platform. Simulation results have been generated
and analyzed for an unbalanced three-phase residential feeder which is populated with rooftop PVs and
battery storage (BS). The simulation results show that the unbalanced reduction due to the coordinate of
PVs and BS that provided educated energy storage when the unequal loadings are there, have significant
effect toward the anxiety of the distribution network are successfully done.
Improved Controller for the Dual Topology of the Unified Power Quality Condit...IRJET Journal
This document presents an improved controller for the dual topology unified power quality conditioner (iUPQC) that extends its applicability for power quality compensation and microgrid applications. The iUPQC can provide reactive power support to regulate the voltage at both the load bus and grid-side bus, acting as a static synchronous compensator (STATCOM) on the grid side while also providing typical UPQC functions like mitigating voltage sags/swells at the load side. Simulation results are provided to validate the new functionality of the device.
IRJET- Improving Power Quality by using MC-UPQCIRJET Journal
This document discusses improving power quality by using a Multiconverter Unified Power Quality Conditioner (MC-UPQC). The MC-UPQC consists of one shunt voltage-source converter (VSC) and two or more series VSCs. It can be applied to adjacent feeders to simultaneously compensate for supply voltage imperfections and load current imperfections on the main feeder, as well as fully compensate supply voltage imperfections on other feeders. The converters are connected back-to-back on the DC side and share a common DC link capacitor, allowing power transfer between feeders. This configuration can compensate for sags/swells and interruptions in both feeders without battery storage. Simulation results will illustrate the performance
Distribution Network Power Quality Improvement by D-STATCOM & DVR Under Vario...IRJET Journal
This document discusses simulation of a Distribution Static Compensator (DSTATCOM) and Dynamic Voltage Restorer (DVR) to improve power quality under fault conditions. It first provides background on power quality issues and defines DSTATCOM and DVR. It then outlines the methodology, including components of each system like the voltage source converter, isolation transformer, and energy storage. The results of simulations showing the DSTATCOM injecting current and DVR injecting voltage during faults to maintain power quality are presented. The document evaluates these custom power devices for mitigating the effects of faults on distribution systems.
2005_A Review of Single-Phase Grid-Connected Inverters.pdfPKSahu6
This document provides a review of single-phase grid-connected inverters for photovoltaic modules. It begins by examining the demands placed on these inverters by utilities, photovoltaic modules, and operators. It then reviews the evolution of photovoltaic inverter technologies from centralized inverters of the past to today's string inverters and ac module technologies. The document categorizes inverter topologies and evaluates them to identify the most suitable for future use with single or multiple photovoltaic modules.
Impact of Electric Vehicle Integration on Gridvivatechijri
Load flow analysis is most essential and important approach to investigate problems in power system. It can provide balance steady state operation of power system without considering transients in it. This project presents a new and efficient method for solving the Load flow problem of a distribution network. By using Backward/Forward sweep method parameters like voltage profile, total power losses, load on each bus of the Distribution Network will be known. By using Load Flow load balancing of the Distribution system can be achieved. For load balancing we will use the power stored in the Electric vehicle. As Electric vehicle has large battery pack for storage. The impact of Electric Vehicle and load flow of distribution network is computer programed to implement the power flow solution scheme in MATLAB software.
IRJET- Improved IUPQC Controller to Provide Grid Voltage as a STATCOMIRJET Journal
This document discusses an improved controller for the integrated Unified Power Quality Conditioner (iUPQC) that expands its capabilities. The iUPQC can now provide reactive power support to regulate both the load bus voltage and grid side bus voltage, allowing it to function as a Static Synchronous Compensator (STATCOM) on the grid side while still providing conventional UPQC compensation on the load side. Experimental results confirm the new functionality of the device. The iUPQC with the enhanced controller provides power quality compensation like a UPQC as well as reactive power and voltage regulation like a STATCOM.
Assessment of the Static Stability Margin and Voltage Profile Improvement in ...Dr. Amarjeet Singh
The huge increase in the demand of electric power and the economic constraints to build new facilities, lead the power systems to operate near of their stability limits. Indeed, instability has become a major problem in the management of power systems. Unavoidable disturbances such as short circuits, momentary unavailability of transmission lines, generators as well as transformers can affect the stability of the power system at any time and bring it into a state of instability or collapse. These collapses become a major problem for energy consumers, because the lack of energy leads them to use backup energy sources that are relatively expensive and polluting. This situation lowers the productivity of the industry, and for the national electric company of the Congo, (SNEL), the time to get rid of the magnetization of the network and to take all the loads, can generate penalties, which is a loss of revenue for the company. This paper aims to assess the stability margin and to improve the quality of electrical energy in the south-SNEL transmission system.
Congestion Management in Deregulated Power System by Using FACTS DevicesIRJET Journal
This document discusses congestion management in deregulated power systems using Flexible AC Transmission System (FACTS) devices. It begins with an introduction to the problem of transmission line overloading and congestion in deregulated power markets. It then discusses how FACTS devices like Thyristor Controlled Series Capacitor (TCSC) can be used to reduce flows in heavily loaded lines and manage congestion. The document presents a case study using the IEEE 14-bus test system and PowerWorld Simulator software to analyze the impact of installing a TCSC on congested lines. It shows that the TCSC is effective at overcoming congestion by changing power flows and making locational marginal prices uniform across the system.
Techno economic study of series current limiting reactor and its impact in th...Alexander Decker
This document presents a techno-economic study of installing series current limiting reactors in an 11kV distribution network to limit fault currents. It describes the electrical network configuration, connected loads including nonlinear loads, and existing fault levels. ETAP system studies were conducted for 0.3 and 0.5 ohm reactor options, including load flow analysis, short circuit studies accounting for variations in source impedance ratio and fault current, and harmonic assessment. The studies showed that both reactor options maintained acceptable voltage regulation but the 0.3 ohm reactor resulted in fault currents below the switchgear rating. Manufacturers of oil-filled reactors were identified.
This chapter examines the economic impact of transmission networks on their users. It discusses how transmission networks can affect system operation costs through losses and constraints. Losses occur as some power is lost as heat during transmission, requiring more generation. Constraints may require more costly generation if cheaper options violate transmission limits. The chapter also notes the importance of location - both in determining the impact of individual users on losses and constraints, and in allocating network costs to users based on their contributing locations.
HIPDN: A POWER DISTRIBUTION NETWORK FOR EFFICIENT ON-CHIP POWER DELIVERY AND ...csijjournal
The document describes a new Power Distribution Network (PDN) called HiPDN that aims to improve power efficiency for integrated circuits. HiPDN uses multiple Integrated Voltage Regulators (IVRs) arranged in multiple stages to efficiently deliver power over a wide range of voltages. The first stage uses switching regulators for high efficiency over a wide output range, while the second stage uses low-dropout regulators optimized for a narrow range. When combined with Adaptive Voltage Scaling techniques, HiPDN can further reduce voltage safety margins to decrease power consumption. Theoretical analysis shows HiPDN can achieve greater power savings than existing PDNs.
HIPDN: A POWER DISTRIBUTION NETWORK FOR EFFICIENT ON-CHIP POWER DELIVERY AND ...csijjournal
While the semiconductor roadmap is about to locate in 16nm-FinFET (or Tri-Gate) era, power budget is being entitled major concern to contemporary electronics and future nanometer devices. In this work, a new Power Distribution Network (PDN), referred to as HiPDN, is disclosed for further fine-grain power saving and higher power integrity for supplies in multi-voltage domains. The proposed PDN employs two types of Integrated Voltage Regulators (IVR) with large difference in voltage regulation range. By combining the proposed PDN with the Adaptive Voltage Scaling (AVS) technique, voltage guard-bands can be mitigated to lower the safety margin for voltage variation, i.e., reducing DC set points, thereby effectively decreasing the overhead of power dissipation. In comparison to existing PDNs, theoretical results with a simple equivalent circuit model demonstrate an increase of power saving achieved by HiPDN, thus, allowing longer battery life. Finally, this work provides an on-chip power delivery methodology to improve power efficiency and a simple model to evaluate a PDN and its IVRs.
Reactive Power Compensation and Power Factor Correction by Reactive VAR Compe...ijtsrd
Power factor improvement for nonlinear loads is the point of interest for researchers in recent scenario. Power factor plays a major role in efficiency of electrical system. The Purpose of this paper is to power factor improvement by using proper control strategy. Simulation on MATLAB Simulink environment is conducted with resistive inductive load. The low power factor is highly undesirable as it causes an increase in current, resulting in additional losses of active power in all the elements of power system from power system down to the utilization devices. To compensate reactive power and improve the power factor by using a static VAR compensator, it consisting converter 2 level SCR with capacitor bank. This work deals with the performance evaluation through analytical studies and practical implementation on an existing system consisting of a distribution transformer of 1phase, 50Hz, 230V 12V capacity. Sadi Mujtaba | Neena Godara "Reactive Power Compensation and Power Factor Correction by Reactive VAR Compensator" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-1 , December 2021, URL: https://www.ijtsrd.com/papers/ijtsrd49100.pdf Paper URL: https://www.ijtsrd.com/engineering/electrical-engineering/49100/reactive-power-compensation-and-power-factor-correction-by-reactive-var-compensator/sadi-mujtaba
Similar to Comprehensive Long-Run Incremental Cost (LRIC)-Voltage Network Pricing Approach to Support Network Voltages Given Contingencies (20)
A Study on Translucent Concrete Product and Its Properties by Using Optical F...IJMER
- Translucent concrete is a concrete based material with light-transferring properties,
obtained due to embedded light optical elements like Optical fibers used in concrete. Light is conducted
through the concrete from one end to the other. This results into a certain light pattern on the other
surface, depending on the fiber structure. Optical fibers transmit light so effectively that there is
virtually no loss of light conducted through the fibers. This paper deals with the modeling of such
translucent or transparent concrete blocks and panel and their usage and also the advantages it brings
in the field. The main purpose is to use sunlight as a light source to reduce the power consumption of
illumination and to use the optical fiber to sense the stress of structures and also use this concrete as an
architectural purpose of the building
Developing Cost Effective Automation for Cotton Seed DelintingIJMER
A low cost automation system for removal of lint from cottonseed is to be designed and
developed. The setup consists of stainless steel drum with stirrer in which cottonseeds having lint is mixed
with concentrated sulphuric acid. So lint will get burn. This lint free cottonseed treated with lime water to
neutralize acidic nature. After water washing this cottonseeds are used for agriculter purpose
Study & Testing Of Bio-Composite Material Based On Munja FibreIJMER
The incorporation of natural fibres such as munja fiber composites has gained
increasing applications both in many areas of Engineering and Technology. The aim of this study is to
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This is mainly due to their applicable benefits as they are light weight and offer low cost compared to
synthetic fibre composites. Munja fibres recently have been a substitute material in many weight-critical
applications in areas such as aerospace, automotive and other high demanding industrial sectors. In
this study, natural munja fibre composites and munja/fibreglass hybrid composites were fabricated by a
combination of hand lay-up and cold-press methods. A new variety in munja fibre is the present work
the main aim of the work is to extract the neat fibre and is characterized for its flexural characteristics.
The composites are fabricated by reinforcing untreated and treated fibre and are tested for their
mechanical, properties strictly as per ASTM procedures.
Hybrid Engine (Stirling Engine + IC Engine + Electric Motor)IJMER
Hybrid engine is a combination of Stirling engine, IC engine and Electric motor. All these 3 are
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The Greenstone belts of Karnataka are enriched in BIFs in Dharwar craton, where Iron
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accumulated at the basin margin and flanking the marine basin. Geochemical data procured in terms of
major, trace and REE are plotted in various diagrams to interpret the genesis of BIFs. Al2O3, Fe2O3 (T),
TiO2, CaO, and SiO2 abundances and ratios show a wide variation. Ni, Co, Zr, Sc, V, Rb, Sr, U, Th,
ΣREE, La, Ce and Eu anomalies and their binary relationships indicate that wherever the terrigenous
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concentrations of Ni, Co and Sc are contributed by chlorite and other components characteristic of basic
volcanic debris. The data suggest that these formations were generated by chemical and clastic
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and textures in Kammatturu area, in a setting where the water column was oxygenated.
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locations. The primary idea employed in this paper, is to model those dynamic loads as equivalent G
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Static Analysis of Go-Kart Chassis by Analytical and Solid Works SimulationIJMER
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determined by performing static analysis. Computed results are then compared to analytical calculation,
where it is found that the location of maximum deflection agrees well with theoretical approximation but
varies on magnitude aspect.
In récent year various vehicle introduced in market but due to limitation in
carbon émission and BS Séries limitd speed availability vehicle in the market and causing of
environnent pollution over few year There is need to decrease dependancy on fuel vehicle.
bicycle is to be modified for optional in the future To implement new technique using change in
pedal assembly and variable speed gearbox such as planetary gear optimise speed of vehicle
with variable speed ratio.To increase the efficiency of bicycle for confortable drive and to
reduce torque appli éd on bicycle. we introduced epicyclic gear box in which transmission done
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Integration of Struts & Spring & Hibernate for Enterprise ApplicationsIJMER
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Microcontroller Based Automatic Sprinkler Irrigation SystemIJMER
Microcontroller based Automatic Sprinkler System is a new concept of using
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sprinkler irrigation work is transformed in to a comfortableautomatic work. This system provides
flexibility & accuracy in respect of time set for the operation of a sprinkler water pipe lines. In present
work the author has designed and developed an automatic sprinkler irrigation system which is
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system are generated using association rule mining and decision trees. Decision trees is generated for
dataset and to find the basic parameters for creating the membership functions of fuzzy inference
system. Membership functions are generated for the probe attack. Based on these rules we have
created the fuzzy inference system that is used as an input to neuro-fuzzy system. Fuzzy inference
system is loaded to neuro-fuzzy toolbox as an input and the final ANFIS structure is generated for
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Today in era of software industry there is no perfect software framework available for
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law with a stress exponent of 5. The composite cylinders are subjected to internal pressure which is
applied gradually and steady state condition of stress is assumed. The creep parameters required to
be used in creep law, are extracted by conducting regression analysis on the available experimental
results. The mathematical models have been developed to describe steady state creep in the composite
cylinder by using von-Mises criterion. Regression analysis is used to obtain the creep parameters
required in the study. The basic equilibrium equation of the cylinder and other constitutive equations
have been solved to obtain creep stresses in the cylinder. The effect of varying particle size, particle
content and temperature on the stresses in the composite cylinder has been analyzed. The study
revealed that the stress distributions in the cylinder do not vary significantly for various combinations
of particle size, particle content and operating temperature except for slight variation observed for
varying particle content. Functionally Graded Materials (FGMs) emerged and led to the development
of superior heat resistant materials.
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Discrete Model of Two Predators competing for One Prey
Comprehensive Long-Run Incremental Cost (LRIC)-Voltage Network Pricing Approach to Support Network Voltages Given Contingencies
1. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.2, Issue.6, Nov-Dec. 2012 pp-4577-4586 ISSN: 2249-6645
Comprehensive Long-Run Incremental Cost (LRIC)-Voltage Network
Pricing Approach to Support Network Voltages Given Contingencies
E. Matlotse, 1 E.T. Rakgati2
1,2
Edwin Matlotse is with the Department of Electrical Engineering, University of Botswana, Botswana,
Abstract: most network charges are based on components’ Restructuring of the respective power systems as voltage
thermal limits providing correct economic signals to instability incidents
reinforcing network transformers and lines. However, less Have been experienced in a number of countries. These, at
attention is drawn to the reinforcement cost driven by times, led to several major voltage collapse scenarios. The
nodal voltage limits, particularly those resulting from Aforementioned voltage instability is due to power systems
contingencies. In this work, a new charging approach is operated tightly to their transmission capability limits
proposed in which busbar power perturbation is linked to against the backdrop of economic and environmental
busbar voltage degradation rate which, in turn, is related concerns. The problem is often compounded by delays in
to the incremental investment cost required to maintain developing transmission lines resulting from lengthy and
voltage levels. The incremental cost results by employing complex approval processes, particular regarding
the use of the nodal voltage spare capacity to gauge the interconnected independent power systems. These
time to invest in a reactive power compensation device for aforementioned effects make it difficult to master the
a defined load growth rate. The time to invest takes into control of reactive power demand and, hence, difficult to
account the network nodal voltage profiles under N-1 retain network nodal voltages within prescribed limits.
circuit contingencies (one line outage at a time). Further, Most research in reactive power pricing [1]-[12] reflects
the nodal MW and MVAr perturbations are considered in the operational cost related to reactive power due to new
this paper. This novel approach is demonstrated on the customers, i.e. how they might affect network losses. Also,
IEEE 14 bus network, illustrating the difference in charges network reactive power pricing has generated substantial
when considering contingencies, therefore, providing research interests into methodologies to reflect investment
correct forward-looking economic signals to potential costs incurred in network when supporting nodal real and
network users. In turn, this will help them make informed reactive power injection/withdrawal [13], [14]-[33],
decisions as to whether to invest in reactive power however, the network investment costs are restricted to the
compensation assets or pay the network operators for circuits and transformers triggered by thermal limits.
reactive power provision. Most importantly, this new Further, this investment does not account for contingencies.
approach outperforms the currently used power factor (pf) The investment cost-related price (ICRP) charging model
penalty. [34] used in the UK does not consider the network security
requirement in the model, but it relies on post-processing
Index Terms: Base LRIC-voltage network charges, CF LRIC- through a full-contingency analysis to give an average
voltage network charges, lower Nodal Voltage Limit, Upper security factor of 1.86 for all concerned network assets.
Nodal Voltage Limit, Contingency Factors, Spare nodal voltage Based upon those latter methodologies, particularly those
capacity and VAr compensation assets. in [20], [26] and [30], the first approach to charge for the
cost of supporting network nodal voltages was developed
I. INTRODUCTION [35], but does not consider the effect on the reinforcement
ONE of the fundamental requirements for network cost from contingencies, hence, it does not consider the
operators is to ensure that network nodal voltages are additional stress to the network when contingencies occur.
within prescribed limits. The natural way of achieving this Further, authors of [36] presented a study on the approach
is by having reactive power sources (static and dynamic on [35] i.e. LRIC-voltage network charges given different
devices) distributed through-out the entire network during network R/X ratios to demonstrate the practical reality of a
its steady state operation and when its experiencing network ranging from a transmission to distribution
credible contingencies. The extent at which this can be infrastructure. On the other hand, authors of [37]-[40]
achieved is sometimes limited by the availability of funds. considered the N-1 contingency analysis into their charging
In this regard, reasonable funding can be used to install just principles and all of these were for pricing of network
adequate reactive power sources and, then as a measure of circuits and transformers based on the thermal use of the
enhancement, an appropriate economic model can be used network. Paper [14] demonstrated a simplistic approach to
to charge for the use of the network reactive power account for N-1 contingencies based on the assumption that
compensation assets to ensure that network voltages are reinforcement is required when a branch thermal power
within predetermined limits. Also, it should be noted that it flow reaches 50% of its capacity. Therefore, it is
is a requirement for network operators to operate their against this background that in this research an approach
infrastructure subject to N-1 circuit contingencies (outage that factor in the effect of N-1 contingencies in the LRIC-
of each line at a time) to guarantee that it operates reliably voltage network charging model in proposed.
and securely. This is even more important under the
prevailing worldwide trend of privatization and
www.ijmer.com 4577 | Page
2. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.2, Issue.6, Nov-Dec. 2012 pp-4577-4586 ISSN: 2249-6645
This paper is concerned with development of network resulting from N-1 contingencies would be shown. Finally,
charges that account for reinforcement cost triggered by this effect of N-1 contingencies would be factored into the
busbar voltage limits under N-1 contingencies. Further, former charging principle to constitute CF (contingency
these are compared with those under normal conditions of factor) LRIC-voltage network charges.
the network. This charging principle employs the use of the
A. Base LRIC-Voltage Network Charging Principle
unused nodal voltage capacity or headroom within an
The following steps outlined below can be utilized to
existing network to gauge time to invest in reactive power
implement this charging model:
compensation device for each node in the system. A nodal
withdrawal/injection of real/reactive power will impact on
1) Evaluating the future investment cost of network VAr
the nodal voltage, which in turn impact on the time to
compensation assets to support existing customers
reinforce reactive power compensation devices. LRIC-V
If a network node b, has lower voltage limit, V L and
network charges are the difference in the present value of
future Var compensation devices with and without the upper voltage limit VH, and holds a voltage level of Vb ,
nodal perturbation, providing an economically efficient then the number of years for the voltage to grow from Vb to
forward-looking pricing signal to influence the siting
and/or reactive power consumption of demand and V L / V H for a given voltage degradation rate vr can be
generation for bettering network voltage profile. It should evaluated from (1.a) or (1.b).
be noted and emphasized that this paper demonstrates the If V L is critical, i.e, bus voltage is less than target voltage,
charging model at nodes without VAr compensation assets 1 pu :
(future VAr assets) and later (not part of this paper) this VL Vb (1 v r ) nbL
undertaking would be extended to nodes with compensation (1.a)
assets (existing VAr assets). Ultimately, the reactive power
planning (RPP) problem (also, not part of this paper) would On the other hand if V H is critical, i.e, bus voltage is more
be integrated with the LRIC-voltage network pricing
than target voltage, 1 pu :
approach, to price for the future and the existing network
VAr compensation assets as the most practical approach to
VH Vb (1 v r ) nbH
employ. In this case, N-1 circuit contingencies should be
considered. (1.b)
This paper is organized as follows: Section II details the
Where: nbL and nbH are the respective numbers of years
mathematical models of the LRIC-voltage network
that takes Vb to reach V L /V H .
charging (base LRIC) principle under normal state and the
impact to network voltages when considering N-1 Reconfiguring equations (1.a) and (1.b) constitute:
contingencies and the resulting LRIC-voltage network
charging formulation considering N-1 contingencies (CF VL
(1 v r ) nbL
LRIC). Section III provides comparison and analyses of Vb
LRIC-voltage charges with and without considering N-1 (2.a)
contingencies on an IEEE 14 bus network. The paper’s VH
conclusions are drawn in Section IV. Section V provides (1 v r ) nbH
Vb
for Appendix which outlines the loading condition of the
(2.b)
test system while References are depicted in Section VI...
II. MATHEMATICAL FORMULATION OF LONG-RUN Then the values of nbL / nbH are
INCREMENTAL COST PRICING BASED ON NODAL
log V L log Vb
SPARE CAPACITY nbL
log(1 v r )
The LRIC-V network charging principle is based upon
the premise that for an assumed nodal generation/load (3.a)
growth rate there will be an associated rate of busbar log V H log Vb
nbH
voltage degradation. Given this assumption the time log(1 v r )
horizon for a busbar to reach its upper /lower voltage limit (3.b)
can be evaluated. Once the limit has been reached, a
compensation device will be placed at the node as the The assumption is that when the node is fully loaded the
future network reinforcement to support the network reinforcement will take effect. This means that investment
voltage profiles. A nodal demand/generation increment will be effected in nbL /nbH years when the node utilization
would affect the future investment horizon. The nodal reaches V L /V H , respectively. At this point an installation
voltage charge would then be the difference in the present of a VAr compensation asset is regarded as the future
value of the future reinforcement consequent to voltage investment that will be needed at the node to support the
with and without the nodal increment voltage.
In this section, the nodal base LRIC-V network charging
principle formulation would be outlined. Thereafter, the 2) Determining the present value of future investment
formulation to reflect the nodal voltage impact on buses cost
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3. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.2, Issue.6, Nov-Dec. 2012 pp-4577-4586 ISSN: 2249-6645
For a given discount rate of d, the present value of the AssetCbL
PVbnewL
future investment in nbL / nbH years will be: (1 d ) nbnewL
(7.a)
AssetCbL
PVbL
(1 d ) nbL AssetCbH
PVbnewH
(4.a) (1 d ) nbnewH
AssetCbH (7.b)
PVbH
(1 d ) nbH
(4.b) The changes in the present values as consequent of the
Where AssetCbL and AssetCbH are the modern equivalent nodal withdrawal/injection QIn are given by (8.a) and
asset cost to cater for supporting voltage due to lower (8.b)
voltage limit and upper voltage limit violations,
respectively. PVbL PVbnewL PV Lb
(8.a)
3). Deriving the incremental cost as a result of an
additional power injection or withdrawal at node N
PVbH PVbnewH PVbH
If the nodal voltage change is VbL / VbH consequent upon
(8.b)
an additional QIn withdrawal/injection at node N, this will The annualized incremental cost of the network items
bring forward/delay the future investment from year nbL/nbH associated with component b is the difference in the present
to nbnewL /nbnewH and when V L is critical values of the future investment due to the reactive power
magnitude change QIn / PIn at node N multiplied by an
For withdrawal VL (Vb VbL ) (1 vr ) nbnewL annuity factor
(5.a) IVbL PVbL * annuityfactor
or (9.a)
For injection VL (Vb VbH ) (1 vr ) nbnewL
IVbH PVbH * annuityfactor
(5.b)
(9.b)
And when V H is critical
4) Evaluating the long-run incremental cost
For withdrawal VH (Vb VbL ) (1 vr ) nbnewH If there are a total of bL busbars’ lower limits and bH
(5.c) busbars’ high limits that are affected by a nodal increment
or from N, then the LRIC-V network charges at node N will
For injection VH (Vb VbH ) (1 vr ) nbnewH be the aggregation of the changes in present value of future
(5.d) incremental costs over all affected nodes:
Equations (6.a), (6.b), (6.c) and (6.d) give the new LRIC _ VN , L
bL IVbL
QIn / PIn
investment horizons as
(10.a)
log V L log(Vb VbL )
nbnewL bH IVbH
log(1 v r ) LRIC _ VN , H
QIn / PIn
(6.a)
or (10.b)
log V L log(Vb VbH )
nbnewL B. Impact to Network Voltage When Considering N-1
log(1 v r )
Contingencies
(6.b) If a network node b supports voltage Vb under the normal
log V H log(Vb VbL ) state and has to carry an additional voltage of VL due to
nbnewH the most severe N-1 contingency situation, then the
log(1 v r )
contingency factor at that node can be determined by (11)
(6.c)
or
Vb V L
log V H log(Vb VbH ) CFL
nbnewH Vb
log(1 v r )
(11)
(6.d)
Given the node has to withstand additional voltage
disturbance, where the magnitude of the disturbance is
Then the new present values of the future investments are
indicated by contingency factor, CFL , the system cannot be
allowed to operate to its limits. Instead, the maximum
www.ijmer.com 4579 | Page
4. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.2, Issue.6, Nov-Dec. 2012 pp-4577-4586 ISSN: 2249-6645
allowed voltage level at each busbar has to be modified to The test system shown above in Fig. 1 is the IEEE 14 bus
cater for potential contingencies. This new nodal voltage network, the load and generation data of this network are
limit for the lower bus voltage limit can be determined by shown in the appendix section. This network consists of
(12) 275kV sub transmission voltage level shown in red and the
132kV distribution voltage level shown in blue. There are
VL two generators and three synchronous compensators. The
VbCF L
CFL synchronous compensators boost the voltage at buses 3, 6, 8
(12) since the subtranmission lines are fairly long. It is also
worthwhile to note that, these synchronous compensators
On the other hand, if a network node b supports voltage have reached their full capacities and, therefore, they
Vb under normal state and has to carry an additional cannot maintain their respective bus voltages at pre-set
voltage levels and, as such, during withdrawals/injections,
voltage of VH due to the most severe N-1 contingency
voltage changes are experienced at the buses where these
situation, then the contingency factor at that node can be are connected. The line distances between the buses are
determined by (13) depicted in blue and red for the sub transmission and
Vb V H distribution levels, respectively. The compensation assets
CFH
Vb (SVCs) have the investment costs of £1, 452,000 and £696,
(13) 960 at the 275-kV and 132-kV voltage levels, respectively.
Given the node has to withstand additional voltage Bus 1 is the slack bus. The voltage limits are assumed to
disturbance, where the magnitude of the disturbance is be1 6% pu. The use of power flow was employed to
indicated by contingency factor, CFH , the system cannot be capture the nodal voltages while performing nodal
allowed to operate to its limits. Instead, the maximum withdrawals/injections on the system. The annual load
allowed voltage level at each busbar has to be modified to growth for this test network is assumed to be 1.6% while
cater for potential contingencies. This new nodal voltage the discount rate is assumed to be 6.9%.
Vb limit for the higher bus voltage limit can be
CF L
A. Base LRIC-Voltage Network Charges
determined by (14) The base LRIC-v network charges are determined by
VH injecting/withdrawing 1 MVAr/1 MW at every node of the
VbCF H
CFH system without subjecting the system to N-1 contingencies.
(14)
Base LRIC-Voltage Network Charges Vs Nodes
C. CF LRIC-Voltage Network Charges Graph(1 MVAr Nodal Withdrawal)
Given the newly determined network lower bus
limit, Vb , and higher bus limit, Vb , to support N-1 10000
CF L CF H
Costs(£/MVAr/yr)
8000
contingencies, these can be utilized in the LRIC-v charging
6000
principle to formulate the CF LRIC-voltage network Base LRIC
charges by replacing V L by the former new limit while 4000
2000
replacing V H by the latter new limit in the relevant
0
equations above. 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Nodes
III. IMPLEMENTATION
1. Test System Fig. 2: Base Nodal LRIC-Voltage Network Charges per
MVAr withdrawal
Buses 2, 7 and 8 have their initial voltages greater than
the target voltage of 1 pu while the rest of buses excluding
the slack bus have their initial voltages below 1 pu.
Withdrawing reactive power would help buses 2, 7, and
8 to be closer to the target voltage, thus should be rewarded
for increasing the margins of the already critical busbar
upper voltage limits. Customers at these buses are
incentivized to take reactive power from the network as the
investment horizons of the VAr compensation assets at the
respective bus are deferred. While the rest of the buses
excluding the slack bus are penalized for reactive power
withdrawal as it decrease the margins to the lower voltage
limits since this action advance the investment horizons of
the VAr compensation assets at the study bus. Although
Fig. 1: IEEE 14 Bus System individual busbars may have charges or credits against the
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same nodal withdrawal, the nodal LRIC-voltage network During nodal injections, the buses (2, 7 & 8) having
price in this system is a charge against each node, since the their initial voltages above 1 pu are penalized for degrading
price accounts for the system wide effects from a nodal the already critical busbar upper voltage limits while the
withdrawal, the credits from buses 2, 7 and 8 are far less the rest except the slack bus are credited for relieving the
than the accumulated charges from the rest of the busbars. already critical busbar lower voltage limits. The same
It can also be observed that the LRIC-voltage network reasons as for nodal withdrawals hold as the overall result
charges generally increase with increasing distance. Bus 3 is that all buses earn credits. Also, observed is that the
has the largest distance but the charge is comparably small, credits increase as distances increase. The conditions in
This is because the bus is connected with a synchronous this case are the same as for the previous case of Fig.2,
Condenser which boosts the voltage at that bus. The same therefore, the pattern remains the same, in that, Bus 12
occurs at bus 6 and 8. The charge at bus 8 is smaller that at attracts the most credit while Bus 2 attracts the least.
bus 7 since bus 8 has its voltage boosted. Even though Bus
14 has a larger distance than buses 12 and 13, as LRIC-Voltage Network Credits Vs Nodes Graph(1
withdrawing from this node has a larger impact to buses 7 MW Nodal Injections)
and 8 which earn larger credit contributing to reduced 0
-500 1 2 3 4 5 6 7 8 9 10 11 12 13 14
overall charge. The same applies to bus 13 since it is closer
Credits(£/MW/yr)
-1000
to buses 7 and 8 than bus 12. Bus 12 under the -1500
-2000 LRIC-V Credits
aforementioned circumstances attracts the most charge -2500
-3000
since it is further from buses 7 and 8 than buses 13 and 14 -3500
resulting in less credit at buses 7 and 8 in contribution to -4000
Node
the overall higher charge at this bus. Bus 2 has the least
charge since it is closer to the slack bus. Fig. 5: Base LRIC-Voltage Network Charges due to 1MW
nodal injections
LRIC-Voltage Network Costs Vs Nodes Graph(1
MW Nodal Withdrawals) It can also be observed from Fig. 5, that the LRIC-v
5000 charges follow the same pattern as those of MVAr nodal
injections, but with less LRIC-v credits for the same
Costs(£/MW/yr)
4000
3000
LRIC-V Costs
reasons relating to the differences depicted above for the
2000
MVAr and MW withdrawals.
1000
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 B. Contingency Factor Terms
Node
The nodal contingency factors reflect additional voltage
Fig. 3: Base LRIC-Voltage Network Charges due to 1MW change that would be incurred following the worst
nodal withdrawal contingency. Since every network bus has both the lower
and upper limits, the contingency factors to cater for both
As it can be observed from Fig. 3, the LRIC-v charges of these limits on each bus were determined, subject to N-1
follow the same pattern as those of MVAr nodal contingencies.
withdrawals in Fig. 2 since the conditions are the same as Fig. 6 and TABLE 1 show lower voltage limit contingency
the latter case, in terms of, respective nodal distances from factors against nodes. In addition, TABLE 1 shows initial,
the slack bus and the initial voltages before nodal and outage voltages and the resulting lower nodal voltage
withdrawals. However, during the MW withdrawals, the limits.
nodal voltages are degraded less than in the case with On the other hand, Fig. 7 and TABLE 2 show higher
MVAr withdrawals and, hence, less resulting LRIC-v Voltage limits contingency factors against nodes. In
network costs. This owes to the fact that the resulting addition, TABLE 2 shows initial, and outage voltages and
network circuit reactance (X) is more that the resulting the Resulting higher nodal voltage limits.
network circuit resistance (R).
1. Test System CFL
Lower Voltage Limit Contingency Factors Vs
Base LRIC-Voltage Charges Vs Nodes Graph(1
Nodes Graph
MVAr Nodal Injection)
6
0
Contingency Factor
5
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Charges(£/MVAr/yr)
-2000 4
3 CFL
-4000
Base LRIC 2
-6000
1
-8000 0
1 2 3 4 5 6 7 8 9 10 11 12 13 14
-10000
Nodes
Nodes
Fig. 6: IEEE 14 bus system lower voltage limit contingency
Fig. 4: Base LRIC-Voltage Network Charges due to
factors at each node
1MVAr nodal injections
TABLE 1
Fig. 4 shows benefits against buses given 1 MVAr nodal
injections.
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LOWER NODAL VOLTAGE LIMIT CONTINGENCY FACTORS HIGHER NODAL VOLTAGE LIMIT CONTINGENCY FACTORS
SUBJECT TO N-1 CONTINGENCIES SUBJECT TO N-1 CONTINGENCIES
Fig. 6 shows a plot of CFL values against nodes given the Fig. 7 shows a plot of CFH values against nodes given the
most severe N-1 contingency condition impacting on each most severe N-1 contingency condition impacting on each
lower voltage bus limit on the IEEE 14 bus test system. higher voltage bus limit on the IEEE 14 bus test system.
TABLE 1 also shows the CFL values against nodes and in TABLE 2 also shows the CFH values against nodes and in
addition the initial voltages before the outages, the outage addition the initial voltages before the outages, the outage
voltages and the resulting new lower voltage limits. voltages and the resulting higher voltage limits.
The largest CFL is recorded at bus 8. The most severe The largest CFH value is recorded at bus 7. The most
outage on this bus was when the line between buses 2 and 3 Severe outage on this bus is when the line between buses 7
is outaged. This particular line was critical in supplying the and 9 was taken out. This outage resulted in a large voltage
necessary apparent power to support the load at bus 3. rise at this bus since this line was critical in linking the sub
During this outage, all the apparent power had to be re- Transmission and most of the distribution side of the
routed along the line between buses 3 and 4. This caused network. Due to this outage the power was re-routed from
the voltage at bus 8 to drop from 1.048 pu to 0.998 pu the line connecting the slack bus to bus 5 and eventually
which corresponds to a bus loading variation from 9.73% from bus 5 through to bus 6 through the transformer to
to 52% with respect to the lower voltage limit. The CFL other buses. The voltage rised from 1.008 Pu to 1.052 Pu
value at bus 7 is the second largest since both This constituted bus loading variation from 56.67% to
aforementioned buses where severely affected by the same 93.17% with reference to the higher voltage limit. The least
outage. The least CFL value is at the slack bus since the CFH value is also at the slack bus since the voltage at this
voltage at this bus remains the same across all the outages. bus remains the same across all the outages.
The results generally show that the more the CFL values The results generally show that the more the CFH values
the more reduced the resulting nodal lower voltage limits. the more reduced the resulting nodal higher voltage limits.
2. Test System CFH C. CF LRIC-Voltage Network Charges
After calculating the contingency factors for the
Higher Voltage Limit Contingency Factors Vs
Nodes Graph
corresponding lower and higher nodal voltage limits then
the CF LRIC-voltage network charges were determined
2 based on those new limits.
Contingency Factor
1.5 Fig. 8 and Fig. 9 show CF LRIC-voltage network
1 CFH
charges due to 1 MVAr and 1MW nodal withdrawals,
respectively. On the other hand, Fig. 10 and Fig. 11 show
0.5
CF LRIC-voltage network charges due to 1 MVAr and MW
0 nodal injections, respectively.
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Nodes
Fig. 7: IEEE 14 bus system higher voltage limit
contingency factors at each node
TABLE 2`
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nodal costs. The following number of nodal lower voltage
CF LRIC-Voltage Network Charges Vs Nodes
Graph(1 MVAr Nodal Withdrawal) limits has been reached, therefore, reinforcements
indications were as follows:
250000 1) During MW withdrawals at buses 2, 3, 4, 5, 7 and 8,
Costs(£/MVAr/yr)
200000 reinforcements were triggered at bus 13.
150000 2) MW withdrawals at buses 6, 9, 10, 11, 12, 13 and 14
CF LRIC triggered reinforcements at buses 5 and 13.
100000
Given the above triggered reinforcements, buses 2, 3, 4,
50000
5, 7 and 8 attract costs around the region of £52, 865.00 to
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14
£55, and 881.00 since they all triggered one reinforcement
Nodes
investment. On the other hand, the rest of the buses,
excluding the slack bus, triggered two reinforcement
Fig. 8: CF LRIC-voltage network charges due to 1 MVAr investments, therefore, comparatively more costs ranging
withdrawal at each node from £162, 645.00 to £163, and 955.00. However, the costs
are relatively more during the 1 MVAr withdrawals since
Since the lower nodal voltage limit margins have been up to three reinforcement investments were triggered.
reduced to support N-1 contingencies, during nodal
withdrawals, a number of lower voltage limits have been CF LRIC-Voltage Network Charges Vs Nodes
reached therefore reinforcements indications were as Graph(1 MVAr Nodal Injection)
follows:
0
1) During withdrawals at buses 2 and 3, the lower voltage 1 2 3 4 5 6 7 8 9 10 11 12 13 14
-2000
limit at bus 13 was reached; therefore, a reinforcement Charges(£/MVAr/yr) -4000
cost was attracted at this bus. At other buses during -6000
these respective withdrawals, some attracted credits -8000 CF LRIC
-10000
(buses 2, 7 and 8) while the rest excluding the slack -12000
bus attracted costs for degrading the respective lower -14000
voltage limit margins. Since bus 3 has more distance -16000
Nodes
from the slack bus it attracted more cost than bus 2.
2) During withdrawals at buses 4, 5, 6, 7, 8, 9, 10, 11 & Fig. 10: CF LRIC-voltage network charges due to 1 MVAr
13 there were lower voltage limit violations at buses 5, injection at each node
and 13, as such, these attracted reinforcement costs.
3) During withdrawal at bus 12, buses 5, 12 and 13 had During nodal injections, there were not limits reached. It
their lower voltage limits reached and, as such, should be noted that the ranges of nodal voltage limits with
attracted reinforcement costs. contingency factors considered is less than that without
4) Lastly, during withdrawal at bus 14, buses 5, 13 and contingency factors considered. This factor leads to more
14 had their lower voltage limits reached; therefore, nodal credits for CF LRIC-voltage network charges than
they attracted some reinforcement costs. base LRIC-voltage network charges. It should also be noted
Since buses 12 and 14 attracted three reinforcement costs that the nodal credits follow the same pattern as the case
have their costs around £218,000.00 while buses 2 and 3 without considering the contingency factors but only
have the least costs around £55,000.00 and £58,000.00 increased credits, therefore bus 12 attracts the most credits
respectively since they attracted only one reinforce ment while bus 2 the least.
Costs.
CF LRIC-Voltage Network Costs Vs Nodes
Graph(1 MW Nodal Withdrawals)
CF LRIC-Voltage Network Credits Vs Nodes
Graph(1 MW Nodal Injections)
200000
0
Costs(£/MW/yr)
150000 -1000 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Credits(£/MW/yr)
-2000
100000 CF LRIC-V Costs
-3000
50000 -4000 CF LRIC-V Credits
-5000
0 -6000
1 2 3 4 5 6 7 8 9 10 11 12 13 14
-7000
Node -8000
Node
Fig. 9: CF LRIC-voltage network charges due to 1 MW
withdrawal at each node Fig. 11: CF LRIC-voltage network charges due to 1 MW
injection at each node
During 1 MW nodal withdrawals, the nodal voltage
changes were relative smaller than in the MVAr nodal It can be seen from Fig. 11 that the results follow the
withdrawals’ case and, as such, the number of nodal lower same pattern as those of Fig. 5, but, the credits sought in
voltage limits reached was few, hence, less comparable the former case are small than in the latter one since the
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network resulting reactance (X) is more than the and efficient usage of the network’s reactive power
corresponding resulting resistance (R) and, hence, less resources.
network nodal voltage increments. Compared with the currently used power factor (pf)
penalty, the proposed novel LRIC-voltage network
IV. CONCLUSIONS charging principle is able to provide correct nodal forward-
This paper presents a novel long-run incremental cost looking charges, incentivizing those network users who
(LRIC) pricing principle to price the cost of network defer overall network investment in VAr compensation
reactive power compensation for keeping the system costs and, otherwise, penalize those who bring closer the
voltages within statutory limits when subjected to N-1 network VAr compensation investment horizons. It should
contingencies. This principle is based on the spare nodal be noted that pf penalty approach only penalizes those
voltage capacity of an existing network to reflect the impact network users who operate below the preset trigger
to the network wide voltage profile and the cost of future threshold but fails to incentivize those that operate above
network VAr compensation consequent upon a nodal the preset pf threshold. In addition, the pf penalty approach
injection/withdrawal, i.e. whether they accelerate or delay was used specifically to recover charges for generator
the need for future network compensation devices. The operating costs, that is, ensuring that network losses are
model is thus cost-reflective and able to provide forward- reduced. Furthermore, different network companies have
looking economic signals to influence network users’ different pf penalty trigger thresholds [42, 43, 44] and, for
behavior in order to minimize the cost of future investment that reason, it can be concluded that there is no solid basis
in VAr compensation. Most importantly, these principles for determining such and, therefore, it is not cost reflective
integrate the MW and MVAr perturbations. [45].
The separation of pricing the use of network for carrying The next phase would be to price for the existing
reactive power (the use of circuits and transformers) and network compensation devices at the nodes where these
Generating reactive power (the use of VAr compensation exist and, ultimately, the reactive power planning (RPP)
Devices) also adds further clarity thus transparency to problem would be integrated with the LRIC-voltage
network users of their respective impact to the future network pricing approach, to price for the future and the
network investment. aforementioned existing network VAr compensation assets
This study was carried-out on a 14-bus network. The as the most practical approach to employ. In this case, N-1
major findings from the demonstrations are summarized as circuit contingencies should be considered.
follows:
1) Both the Base and CF LRIC-V network charges V. APPENDIX
increase as the nodal withdrawal/injection distances The used IEEE 14 bus network is described in detail in
increase from the slack bus and the extent at which the [46]. The loading and the generation conditions of this
buses are utilized. used network are shown below in TABLES, 3 and 4,
2). the base LRIC-V network charges do not take into respectively.
Account N-1 contingencies which are a statutory
requirement for network operators to maintain security TABLE 3
of supply, therefore, provide incorrect price signals. IEEE 14 NETWORK LOAD DATA
3). The CF LRIC-V network charges consider N-1
contingencies, accounting for the additional cost
brought to the network operator, therefore, provide
more cost-reflective economic signals for network
users to make informed decisions.
4). The CF LRIC-V network charges are more than base
LRIC-V network charges since each network bus
voltage Limit range (both the lower and higher limit
margins are Reduced) used for determining the former
is reduced to Accommodate the constraints of
supporting N-1 Contingencies and, as such, each
network bus headroom is Inherently reduced.
This paper demonstrated a very simplistic approach to
determine the cost/benefit of LRIC-voltage network charges
on a system subjected to N-1 contingencies (which is a
statutory requirement for network operators) and, further,
compared the charges when these contingencies are
considered and when not considered. The charges with N-1
contingencies provide better economic signals to potential
network users which, in turn, will help them to exercise an
economic choice as to whether to invest in reactive power
devices or pay the network operators for reactive power
provision. Ultimately, this will guide towards an effective
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