Distribution factors have been extensively used in many power system analysis and planning studies. In recent power system studies, the AC distribution factors are insensitive to the operating point and relatively sensitive at certain degree to changes in network topology. These factors are linear approximations of sensitivities of variables with various inputs. This paper presents the calculation of the universal distribution factors (UDF’s) applies them on several practical scenarios of Saudi Electricity Company (SEC) power grid. The results are analyzed and evaluated considering various system conditions of SEC load. The results show that the accuracy of the used approach is acceptable compared with exact method. This is practically beneficial to SEC in computing its grid complex power flows using UDF's at the base case without the need to recalculate UDF’s which save efforts and time.
Power Flow Analysis for Four Buses System by NR Methodijtsrd
Power flow studies provide a systematic mathematical approach for determination of various bus voltages, there phase angle, active and reactive power flows through different branches, generators and loads under steady state condition. In this paper, the purpose of power flow analysis is to determine four bus system power flows. Case studies have been performed on Lawpita Taungoo Kamarnat Hlawga 230kV Line Myanmar . This paper presents a reliable method to meet the requirements by developing a Newton Raphson based load flow calculation program through which control setting of Shunt Compensator can be determined directly. This program computes the voltage magnitude and angle at each bus in a power system under balanced steady state conditions. Real and reactive power flows for all buses, as well as line flow and line losses, are also computed. And then the compensation of shunt capacitor is proposed for load flow analysis and also for overall loss minimization and improvement in system voltage profile. Wint Yu Yu Zaw ""Power Flow Analysis for Four Buses System by NR Method"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23472.pdf
Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/23472/power-flow-analysis-for-four-buses-system-by-nr-method/wint-yu-yu-zaw
Active Distribution Grid Power Flow Analysis using Asymmetrical Hybrid Techni...IJECEIAES
A conventional distribution power flow analysis has to be improved regards the changes in distribution network. One of the changes is a grid operation because a new grid concept, e.g. micro-grid and aggregation, is aimed to be operated based on area itself. Consequently, each area can be actively operated in either grid connected mode or islanding mode. Hence, this paper proposes an asymmetrical power flow analysis using hybrid technique to support this flexible mode change. The hybrid technique offers an opportunity to analyze power flow in a decoupling way. This means that the power flow analysis can be performed separately in each grid area. Regards the distributed generation, this paper also introduces a model based on inverter-based operation, i.e. grid forming, grid supporting and grid parallel. The proposed asymmetrical hybrid load flow method is examined in three case studies, i.e. a verification study with the DIgSILENT PowerFactory, a demonstration of decoupling analysis approach and a performance study with the Newton-Raphson method.
The effect of load modelling on phase balancing in distribution networks usin...IJECEIAES
Due to the unequal loads in phases and different customer consumption, the distribution network is unbalanced. Unbalancing in the distribution network, in addition to increasing power losses, causes unbalancing in voltages and increases operating costs. To reduce this unbalancing, various methods and algorithms have been presented. In most studies and even practical projects due to lack of information about the network loads, load models such as constant power model, constant current or constant impedance are used to model the loads. Due to the changing and nonlinear behaviours of today's loads, these models cannot show results in accordance with reality. This paper while introducing an optimal phase-balancing method, discusses the effect of load modelling on phase balancing studies. In this process the re-phasing method for balancing the network and the harmony search algorithm for optimizing the phase displacement process have been used. The simulation was carried out on an unbalanced distribution network of 25 buses. The results show well the effect of this comprehensive modelling on phase balancing studies. It also shows that in the re-phasing method for balancing the network and in the absence of a real load model, the use of which model offers the closest answer to optimal solutions.
Bulk power system availability assessment with multiple wind power plants IJECEIAES
The use of renewable non-conventional energy sources, as wind electric power energy and photovoltaic solar energy, has introduced uncertainties in the performance of bulk power systems. The power system availability has been employed as a useful tool for planning power systems; however, traditional methodologies model generation units as a component with two states: in service or out of service. Nevertheless, this model is not useful to model wind power plants for availability assessment of the power system. This paper used a statistical representation to model the uncertainty of power injection of wind power plants based on the central moments: mean value, variance, skewness and kurtosis. In addition, this paper proposed an availability assessment methodology based on application of this statistical model, and based on the 2m+1 point estimate method the availability assessment is performed. The methodology was tested on the IEEE-RTS assuming the connection of two wind power plants and different correlation among the behavior of these plants.
Power Flow Analysis for Four Buses System by NR Methodijtsrd
Power flow studies provide a systematic mathematical approach for determination of various bus voltages, there phase angle, active and reactive power flows through different branches, generators and loads under steady state condition. In this paper, the purpose of power flow analysis is to determine four bus system power flows. Case studies have been performed on Lawpita Taungoo Kamarnat Hlawga 230kV Line Myanmar . This paper presents a reliable method to meet the requirements by developing a Newton Raphson based load flow calculation program through which control setting of Shunt Compensator can be determined directly. This program computes the voltage magnitude and angle at each bus in a power system under balanced steady state conditions. Real and reactive power flows for all buses, as well as line flow and line losses, are also computed. And then the compensation of shunt capacitor is proposed for load flow analysis and also for overall loss minimization and improvement in system voltage profile. Wint Yu Yu Zaw ""Power Flow Analysis for Four Buses System by NR Method"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23472.pdf
Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/23472/power-flow-analysis-for-four-buses-system-by-nr-method/wint-yu-yu-zaw
Active Distribution Grid Power Flow Analysis using Asymmetrical Hybrid Techni...IJECEIAES
A conventional distribution power flow analysis has to be improved regards the changes in distribution network. One of the changes is a grid operation because a new grid concept, e.g. micro-grid and aggregation, is aimed to be operated based on area itself. Consequently, each area can be actively operated in either grid connected mode or islanding mode. Hence, this paper proposes an asymmetrical power flow analysis using hybrid technique to support this flexible mode change. The hybrid technique offers an opportunity to analyze power flow in a decoupling way. This means that the power flow analysis can be performed separately in each grid area. Regards the distributed generation, this paper also introduces a model based on inverter-based operation, i.e. grid forming, grid supporting and grid parallel. The proposed asymmetrical hybrid load flow method is examined in three case studies, i.e. a verification study with the DIgSILENT PowerFactory, a demonstration of decoupling analysis approach and a performance study with the Newton-Raphson method.
The effect of load modelling on phase balancing in distribution networks usin...IJECEIAES
Due to the unequal loads in phases and different customer consumption, the distribution network is unbalanced. Unbalancing in the distribution network, in addition to increasing power losses, causes unbalancing in voltages and increases operating costs. To reduce this unbalancing, various methods and algorithms have been presented. In most studies and even practical projects due to lack of information about the network loads, load models such as constant power model, constant current or constant impedance are used to model the loads. Due to the changing and nonlinear behaviours of today's loads, these models cannot show results in accordance with reality. This paper while introducing an optimal phase-balancing method, discusses the effect of load modelling on phase balancing studies. In this process the re-phasing method for balancing the network and the harmony search algorithm for optimizing the phase displacement process have been used. The simulation was carried out on an unbalanced distribution network of 25 buses. The results show well the effect of this comprehensive modelling on phase balancing studies. It also shows that in the re-phasing method for balancing the network and in the absence of a real load model, the use of which model offers the closest answer to optimal solutions.
Bulk power system availability assessment with multiple wind power plants IJECEIAES
The use of renewable non-conventional energy sources, as wind electric power energy and photovoltaic solar energy, has introduced uncertainties in the performance of bulk power systems. The power system availability has been employed as a useful tool for planning power systems; however, traditional methodologies model generation units as a component with two states: in service or out of service. Nevertheless, this model is not useful to model wind power plants for availability assessment of the power system. This paper used a statistical representation to model the uncertainty of power injection of wind power plants based on the central moments: mean value, variance, skewness and kurtosis. In addition, this paper proposed an availability assessment methodology based on application of this statistical model, and based on the 2m+1 point estimate method the availability assessment is performed. The methodology was tested on the IEEE-RTS assuming the connection of two wind power plants and different correlation among the behavior of these plants.
Framework Development to Analyze the Distribution System for Upper Karnali Hy...IJMERJOURNAL
ABSTRACT: Upper Karnali Hydropower Project is a 900 MW run of river hydro project in Nepal, from where the generated power will be transmitted to Indian grid via a dedicated transmission line, and hence local consumers will not be fed through this plant. As per the concession agreement executed between the Government of Nepal and the developers, a 2 MW hydro plant shall be developed at the toe of the dam by using the environmental release discharge. A previous study conducted by the authors, identified the optimal electric network, taking into consideration different factors such as demography, topography, socio-economic and technical feasibility. In this study, however, the authors analyze the performance of the system by carrying out a techno-economic study using computational grid network design analysis. A framework for Load Flow Analysis is developed and used to analyze the developed network. For verification, the results obtained are compared with those from standard 33 bus radial distribution feeder system and Forward/Backward based Sweep algorithm creating paired sample T-test. No significant difference between the results for a 95% confidence of interval is observed. After observing the results, it is concluded that the developed framework, as well as the grid network, are technical, computationally and economically efficient.
Kalman Filter Estimation of Impedance Parameters for Medium Transmission LineTELKOMNIKA JOURNAL
Accurate knowledge of impedance parameters in transmission line helps to improve the system efficiency and performance. Nowadays, the estimation of impedance parameters in transmission line has become possible with the availability of computational method. This paper aims to develop Kalman filter model by using Matlab simulink to estimate accurate values of resistance (R), reactance (X), and susceptance (B) in medium transmission line. The accuracy of the parameters can be improved by reducing the unknown errors in the system. To demonstrate the effectiveness of the Kalman filter method, a case study of simulated medium transmission line is presented and comparison between Kalman Filter (KF) and Linear Least Square (LLS) method is also considered to evaluate their performances.
Power system state estimation using teaching learning-based optimization algo...TELKOMNIKA JOURNAL
The main goal of this paper is to formulate power system state estimation (SE) problem as a constrained nonlinear programming problem with various constraints and boundary limits on the state variables. SE forms the heart of entire real time control of any power system. In real time environment, the state estimator consists of various modules like observability analysis, network topology processing, SE and bad data processing. The SE problem formulated in this work is solved using teaching leaning-based optimization (TLBO) technique. Difference between the proposed TLBO and the conventional optimization algorithms is that TLBO gives global optimum solution for the present problem. To show the suitability of TLBO for solving SE problem, IEEE 14 bus test system has been selected in this work. The results obtained with TLBO are also compared with conventional weighted least square (WLS) technique and evolutionary based particle swarm optimization (PSO) technique.
Convergence analysis of the triangular-based power flow method for AC distribu...IJECEIAES
This paper addresses the convergence analysis of the triangular-based power flow (PF) method in alternating current radial distribution networks. The PF formulation is made via upper-triangular matrices, which enables finding a general iterative PF formula that does not require admittance matrix calculations. The convergence analysis of this iterative formula is carried out by applying the Banach fixed-point theorem (BFPT), which allows demonstrating that under an adequate voltage profile the triangular-based PF always converges. Numerical validations are made, on the well-known 33 and 69 distribution networks test systems. Gauss-seidel, newton-raphson, and backward/forward PF methods are considered for the sake of comparison. All the simulations are carried out in MATLAB software.
This paper based on review of load flow analysis of radial distribution system. The
problem on unbalancing of reactive power is in single phase and three phases. Therefore to improve &
enhancing voltage profile and stability of the existing power system, load flow analysis is alternative
solution. Here is review on different approaches by different author’s for load flow analysis in three phase
radial distribution system to improve voltage stability and to minimize the transmission line losses.
Different optimization techniques may be use to identify as well as applied in three phase radial
distribution system with analysis of different authors review and based on merits and demerits of radial
distribution system. Local search optimization is also described based on this review.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Review of the UPFC Different Models in Recent YearsIJPEDS-IAES
Unified Power Flow Controller (UPFC) is one of the most intriguing and, potentially, the most versatile classes of Flexible AC Transmission Systems (FACTS) devices. The UPFC is a device which can control simultaneously tree parameters line impedance, voltage, phase angle and dynamic compensation of AC power system. In order to analyze its true effects on power systems, it is important to model its constraints, due to various ratings and operating limits. This paper reviews on the different models of UPFC used in recent years and gives sets of information for each model of the UPFC in AC transmission. Then the different models are compared and features of each model are examined.
A modified backward/forward sweep-based method for reconfiguration of unbalan...IJECEIAES
A three-phase unbalanced power flow method can provide a more realistic scenario of how distribution networks operate. The backward/forward sweep-based power flow method (BF-PF) has been used for many years as an important computational tool to solve the power flow for unbalanced and radial power systems. However, some of the few available research tools produce many errors when they are used for network reconfiguration because the topology changesafter multiple switch actions and the nodes are disorganized continually. This paper presents a modifiedBF-PF for three-phase unbalanced radial distribution networks that is capable of arranging the system topology when reconfiguration changes the branch connections. A binary search is used to determine the connections between nodes, allowing the algorithm to avoid those problems when reconfiguration is carried out, regardless of node numbers. Tests are made to verify the usefulness of the proposed algorithm in both the IEEE 13-node test feeder and the 123-node test feeder, converging in every run where constraints are accomplished. This approach can be used easily for a large-scale feeder network reconfiguration. The full version of this modified backward/forward sweep algorithm is available for research at MathWorks.
Selective localization of capacitor banks considering stability aspects in po...IAEME Publication
The issue of voltage stability has become predominant in larger power systems, since the
system is operated close to its capabilities in recent years. Addressing this concern considering the
economic constraints is a challenge .This draws attention towards the localization of the reactive
components that can improve the overall voltage profile in the system. This paper discusses a
methodology for suitable selection of position (bus) for the placement of capacitor bank wherein the
injection of fixed amount of reactive power is made to depict a picture of the overall improved
voltage in the system considering the stability aspect for respective injection at that bus. The reduced
jacobian is used to determine the impact of reactive power injection in the form of system voltage
improvement.
A novel method for determining fixed running time in operating electric train...IJECEIAES
Tracking the optimal speed profile in electric train operation has been proposed as a potential solution for reducing energy consumption in electric train operation, at no cost to improve infrastructure of existing Metro lines as well. However, the optimal speed profile needs to meet fixed running time. Therefore, this paper focuses on a new method for determining the fixed running time complied with the scheduled timetable when trains track the optimal speed profile. The novel method to ensure the fixed running time is the numerical-analytical one. Calculating accelerating time ta, coasting time tc, braking time tb via values of holding speed vh, braking speed vb of optimal speed profile with the constraint condition: the running time equal to the demand time. The other hands, vh and vb are determined by solving nonlinear equations with constraint conditions. Additionally, changing running time suit for each operation stage of metro lines or lines starting to conduct schedules by the numerical-analytical method is quite easy. Simulation results obtained for two scenarios with data collected from electrified trains of Cat Linh-Ha Dong metro line, Vietnam show that running time complied with scheduled timetables, energy saving by tracking optimal speed profile for the entire route is up to 8.7%, if the running time is one second longer than original time, energy saving is about 11.96%.
A Review on Optimal Location and Parameter Settings of FACTS Devices in Power...IJMTST Journal
Flexible Alternating Current Transmission Systems (FACTS) devices have been proposed as an effective
solution for controlling power flow and regulating bus voltages in electrical power systems, resulting low
system losses, and improved stability. Placement of these devices in suitable location can lead to control in
line flow and maintain bus voltages in desired level. The FACTS devices placement problem is commonly
solved using heuristic optimization techniques which are diverse and have been the subject of ongoing
enhancements. This paper presents a survey of the literature from the last decade that has focused on the
various techniques applied to determine optimal location of FACTS devices.
Several models and methods have been suggested for the optimal location and parameter setting of
FACTS devices. This paper presents an overview of the state of the art models and methods applied to the
power system problems, analyzing and classifying current trends in this field.
Time-domain harmonic extraction algorithms for three-level inverter-based sh...IJECEIAES
Power quality is a major consideration in all office equipment, manufacturies and residential home appliances. Harmonic distortion is one of the crucial power quality issues. In order to mitigate the harmonic distortion, the performance of shunt active power filter (SAPF) is judged in terms of the accuracy and response time of its designed controller. In this context, the controller consists of three parts: harmonic extraction, switching control, and DC-link capacitor. The harmonic extraction technique serves the major role of deriving the required reference current to ensure successful mitigation of current harmonics by SAPF. Among the existing techniques, harmonic extraction algorithms based on time-domain approaches are most widely applied as they offer simple implementation features with increased speed and reduced computational burden. This paper presents detailed investigation and analysis regarding the performance of two famous time-domain harmonic extraction techniques namely, synchronous reference frame (SRF) and instantaneous power (PQ) theory. Extensive simulation work is conducted in MATLAB-Simulink platform under two conditions, which are, steady-state conditions and dynamic-state conditions, considering various highly nonlinear loads. For evaluation purposes, each control algorithm is incorporated into the controller of a three-phase SAPF, developed using a three-level neutral-point-clamped (NPC) inverter. Comprehensive results are provided to confirm mitigation performance of the SAPF utilizing each harmonic extraction algorithm.
Frequency regulation service of multiple-areas vehicle to grid application in...IJECEIAES
Regarding a potential of electric vehicles, it has been widely discussed that the electric vehicle can be participated in electricity ancillary services. Among the ancillary service products, the system frequency regulation is often considered. However, the participation in this service has to be conformed to the hierarchical frequency control architecture. Therefore, the vehicle to grid (V2G) application in this article is proposed in the term of multiple-areas of operation. The multiple-areas in this article are concerned as parking areas, which the parking areas can be implied as a V2G operator. From that, V2G operator can obtain the control signal from hierarchical control architecture for power sharing purpose. A power sharing concept between areas is fulfilled by a proposed adaptive droop factor based on battery state of charge and available capacity of parking area. A nonlinear multiplier factor is used for the droop adaptation. An available capacity is also applied as a limitation for the V2G operation. The available capacity is analyzed through a stochastic character. As the V2G application has to be cooperated with the hierarchical control functions, i.e. primary control and secondary control, then the effect of V2G on hierarchical control functions is investigated and discussed.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
ACTIVE POWER AND COST ALLOCATION IN OPEN ACCESS ENVIRONMENT UTILIZING POWER F...ecij
The transmission usage cost allocation is one of the major issues experienced by the Electric Supply Industries. In this paper, authors have considered Line Outage Distribution Factor (LODF) for allocating the transmission usage cost allocation under contingency condition. Authors have modified the
distribution factor for maximum flow and propose a novel Maximum Line Outage Distribution Factor (MLODF) which depends upon the redistribution of the generation in the line flow considering N-1 security constraints. Similarly, for transmission loss cost allocation under contingency condition Maximum Line Outage Loss Distribution Factor (MLOLDF) is developed. Full recovery policy of transmission cost allocation is considered. The reliability and accuracy of the proposed method is tested
on the sample 6 bus system.
Active power and cost allocation in open access environment utilizing power f...ecij
The transmission usage cost allocation is one of the major issues experienced by the Electric Supply Industries. In this paper, authors have considered Line Outage Distribution Factor (LODF) for allocating the transmission usage cost allocation under contingency condition. Authors have modified the distribution factor for maximum flow and propose a novel Maximum Line Outage Distribution Factor (MLODF) which depends upon the redistribution of the generation in the line flow considering N-1 security constraints. Similarly, for transmission loss cost allocation under contingency condition Maximum Line Outage Loss Distribution Factor (MLOLDF) is developed. Full recovery policy of transmission cost allocation is considered. The reliability and accuracy of the proposed method is tested on the sample 6 bus system.
Framework Development to Analyze the Distribution System for Upper Karnali Hy...IJMERJOURNAL
ABSTRACT: Upper Karnali Hydropower Project is a 900 MW run of river hydro project in Nepal, from where the generated power will be transmitted to Indian grid via a dedicated transmission line, and hence local consumers will not be fed through this plant. As per the concession agreement executed between the Government of Nepal and the developers, a 2 MW hydro plant shall be developed at the toe of the dam by using the environmental release discharge. A previous study conducted by the authors, identified the optimal electric network, taking into consideration different factors such as demography, topography, socio-economic and technical feasibility. In this study, however, the authors analyze the performance of the system by carrying out a techno-economic study using computational grid network design analysis. A framework for Load Flow Analysis is developed and used to analyze the developed network. For verification, the results obtained are compared with those from standard 33 bus radial distribution feeder system and Forward/Backward based Sweep algorithm creating paired sample T-test. No significant difference between the results for a 95% confidence of interval is observed. After observing the results, it is concluded that the developed framework, as well as the grid network, are technical, computationally and economically efficient.
Kalman Filter Estimation of Impedance Parameters for Medium Transmission LineTELKOMNIKA JOURNAL
Accurate knowledge of impedance parameters in transmission line helps to improve the system efficiency and performance. Nowadays, the estimation of impedance parameters in transmission line has become possible with the availability of computational method. This paper aims to develop Kalman filter model by using Matlab simulink to estimate accurate values of resistance (R), reactance (X), and susceptance (B) in medium transmission line. The accuracy of the parameters can be improved by reducing the unknown errors in the system. To demonstrate the effectiveness of the Kalman filter method, a case study of simulated medium transmission line is presented and comparison between Kalman Filter (KF) and Linear Least Square (LLS) method is also considered to evaluate their performances.
Power system state estimation using teaching learning-based optimization algo...TELKOMNIKA JOURNAL
The main goal of this paper is to formulate power system state estimation (SE) problem as a constrained nonlinear programming problem with various constraints and boundary limits on the state variables. SE forms the heart of entire real time control of any power system. In real time environment, the state estimator consists of various modules like observability analysis, network topology processing, SE and bad data processing. The SE problem formulated in this work is solved using teaching leaning-based optimization (TLBO) technique. Difference between the proposed TLBO and the conventional optimization algorithms is that TLBO gives global optimum solution for the present problem. To show the suitability of TLBO for solving SE problem, IEEE 14 bus test system has been selected in this work. The results obtained with TLBO are also compared with conventional weighted least square (WLS) technique and evolutionary based particle swarm optimization (PSO) technique.
Convergence analysis of the triangular-based power flow method for AC distribu...IJECEIAES
This paper addresses the convergence analysis of the triangular-based power flow (PF) method in alternating current radial distribution networks. The PF formulation is made via upper-triangular matrices, which enables finding a general iterative PF formula that does not require admittance matrix calculations. The convergence analysis of this iterative formula is carried out by applying the Banach fixed-point theorem (BFPT), which allows demonstrating that under an adequate voltage profile the triangular-based PF always converges. Numerical validations are made, on the well-known 33 and 69 distribution networks test systems. Gauss-seidel, newton-raphson, and backward/forward PF methods are considered for the sake of comparison. All the simulations are carried out in MATLAB software.
This paper based on review of load flow analysis of radial distribution system. The
problem on unbalancing of reactive power is in single phase and three phases. Therefore to improve &
enhancing voltage profile and stability of the existing power system, load flow analysis is alternative
solution. Here is review on different approaches by different author’s for load flow analysis in three phase
radial distribution system to improve voltage stability and to minimize the transmission line losses.
Different optimization techniques may be use to identify as well as applied in three phase radial
distribution system with analysis of different authors review and based on merits and demerits of radial
distribution system. Local search optimization is also described based on this review.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Review of the UPFC Different Models in Recent YearsIJPEDS-IAES
Unified Power Flow Controller (UPFC) is one of the most intriguing and, potentially, the most versatile classes of Flexible AC Transmission Systems (FACTS) devices. The UPFC is a device which can control simultaneously tree parameters line impedance, voltage, phase angle and dynamic compensation of AC power system. In order to analyze its true effects on power systems, it is important to model its constraints, due to various ratings and operating limits. This paper reviews on the different models of UPFC used in recent years and gives sets of information for each model of the UPFC in AC transmission. Then the different models are compared and features of each model are examined.
A modified backward/forward sweep-based method for reconfiguration of unbalan...IJECEIAES
A three-phase unbalanced power flow method can provide a more realistic scenario of how distribution networks operate. The backward/forward sweep-based power flow method (BF-PF) has been used for many years as an important computational tool to solve the power flow for unbalanced and radial power systems. However, some of the few available research tools produce many errors when they are used for network reconfiguration because the topology changesafter multiple switch actions and the nodes are disorganized continually. This paper presents a modifiedBF-PF for three-phase unbalanced radial distribution networks that is capable of arranging the system topology when reconfiguration changes the branch connections. A binary search is used to determine the connections between nodes, allowing the algorithm to avoid those problems when reconfiguration is carried out, regardless of node numbers. Tests are made to verify the usefulness of the proposed algorithm in both the IEEE 13-node test feeder and the 123-node test feeder, converging in every run where constraints are accomplished. This approach can be used easily for a large-scale feeder network reconfiguration. The full version of this modified backward/forward sweep algorithm is available for research at MathWorks.
Selective localization of capacitor banks considering stability aspects in po...IAEME Publication
The issue of voltage stability has become predominant in larger power systems, since the
system is operated close to its capabilities in recent years. Addressing this concern considering the
economic constraints is a challenge .This draws attention towards the localization of the reactive
components that can improve the overall voltage profile in the system. This paper discusses a
methodology for suitable selection of position (bus) for the placement of capacitor bank wherein the
injection of fixed amount of reactive power is made to depict a picture of the overall improved
voltage in the system considering the stability aspect for respective injection at that bus. The reduced
jacobian is used to determine the impact of reactive power injection in the form of system voltage
improvement.
A novel method for determining fixed running time in operating electric train...IJECEIAES
Tracking the optimal speed profile in electric train operation has been proposed as a potential solution for reducing energy consumption in electric train operation, at no cost to improve infrastructure of existing Metro lines as well. However, the optimal speed profile needs to meet fixed running time. Therefore, this paper focuses on a new method for determining the fixed running time complied with the scheduled timetable when trains track the optimal speed profile. The novel method to ensure the fixed running time is the numerical-analytical one. Calculating accelerating time ta, coasting time tc, braking time tb via values of holding speed vh, braking speed vb of optimal speed profile with the constraint condition: the running time equal to the demand time. The other hands, vh and vb are determined by solving nonlinear equations with constraint conditions. Additionally, changing running time suit for each operation stage of metro lines or lines starting to conduct schedules by the numerical-analytical method is quite easy. Simulation results obtained for two scenarios with data collected from electrified trains of Cat Linh-Ha Dong metro line, Vietnam show that running time complied with scheduled timetables, energy saving by tracking optimal speed profile for the entire route is up to 8.7%, if the running time is one second longer than original time, energy saving is about 11.96%.
A Review on Optimal Location and Parameter Settings of FACTS Devices in Power...IJMTST Journal
Flexible Alternating Current Transmission Systems (FACTS) devices have been proposed as an effective
solution for controlling power flow and regulating bus voltages in electrical power systems, resulting low
system losses, and improved stability. Placement of these devices in suitable location can lead to control in
line flow and maintain bus voltages in desired level. The FACTS devices placement problem is commonly
solved using heuristic optimization techniques which are diverse and have been the subject of ongoing
enhancements. This paper presents a survey of the literature from the last decade that has focused on the
various techniques applied to determine optimal location of FACTS devices.
Several models and methods have been suggested for the optimal location and parameter setting of
FACTS devices. This paper presents an overview of the state of the art models and methods applied to the
power system problems, analyzing and classifying current trends in this field.
Time-domain harmonic extraction algorithms for three-level inverter-based sh...IJECEIAES
Power quality is a major consideration in all office equipment, manufacturies and residential home appliances. Harmonic distortion is one of the crucial power quality issues. In order to mitigate the harmonic distortion, the performance of shunt active power filter (SAPF) is judged in terms of the accuracy and response time of its designed controller. In this context, the controller consists of three parts: harmonic extraction, switching control, and DC-link capacitor. The harmonic extraction technique serves the major role of deriving the required reference current to ensure successful mitigation of current harmonics by SAPF. Among the existing techniques, harmonic extraction algorithms based on time-domain approaches are most widely applied as they offer simple implementation features with increased speed and reduced computational burden. This paper presents detailed investigation and analysis regarding the performance of two famous time-domain harmonic extraction techniques namely, synchronous reference frame (SRF) and instantaneous power (PQ) theory. Extensive simulation work is conducted in MATLAB-Simulink platform under two conditions, which are, steady-state conditions and dynamic-state conditions, considering various highly nonlinear loads. For evaluation purposes, each control algorithm is incorporated into the controller of a three-phase SAPF, developed using a three-level neutral-point-clamped (NPC) inverter. Comprehensive results are provided to confirm mitigation performance of the SAPF utilizing each harmonic extraction algorithm.
Frequency regulation service of multiple-areas vehicle to grid application in...IJECEIAES
Regarding a potential of electric vehicles, it has been widely discussed that the electric vehicle can be participated in electricity ancillary services. Among the ancillary service products, the system frequency regulation is often considered. However, the participation in this service has to be conformed to the hierarchical frequency control architecture. Therefore, the vehicle to grid (V2G) application in this article is proposed in the term of multiple-areas of operation. The multiple-areas in this article are concerned as parking areas, which the parking areas can be implied as a V2G operator. From that, V2G operator can obtain the control signal from hierarchical control architecture for power sharing purpose. A power sharing concept between areas is fulfilled by a proposed adaptive droop factor based on battery state of charge and available capacity of parking area. A nonlinear multiplier factor is used for the droop adaptation. An available capacity is also applied as a limitation for the V2G operation. The available capacity is analyzed through a stochastic character. As the V2G application has to be cooperated with the hierarchical control functions, i.e. primary control and secondary control, then the effect of V2G on hierarchical control functions is investigated and discussed.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
ACTIVE POWER AND COST ALLOCATION IN OPEN ACCESS ENVIRONMENT UTILIZING POWER F...ecij
The transmission usage cost allocation is one of the major issues experienced by the Electric Supply Industries. In this paper, authors have considered Line Outage Distribution Factor (LODF) for allocating the transmission usage cost allocation under contingency condition. Authors have modified the
distribution factor for maximum flow and propose a novel Maximum Line Outage Distribution Factor (MLODF) which depends upon the redistribution of the generation in the line flow considering N-1 security constraints. Similarly, for transmission loss cost allocation under contingency condition Maximum Line Outage Loss Distribution Factor (MLOLDF) is developed. Full recovery policy of transmission cost allocation is considered. The reliability and accuracy of the proposed method is tested
on the sample 6 bus system.
Active power and cost allocation in open access environment utilizing power f...ecij
The transmission usage cost allocation is one of the major issues experienced by the Electric Supply Industries. In this paper, authors have considered Line Outage Distribution Factor (LODF) for allocating the transmission usage cost allocation under contingency condition. Authors have modified the distribution factor for maximum flow and propose a novel Maximum Line Outage Distribution Factor (MLODF) which depends upon the redistribution of the generation in the line flow considering N-1 security constraints. Similarly, for transmission loss cost allocation under contingency condition Maximum Line Outage Loss Distribution Factor (MLOLDF) is developed. Full recovery policy of transmission cost allocation is considered. The reliability and accuracy of the proposed method is tested on the sample 6 bus system.
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Predicting Post Outage Transmission Line Flows using Linear Distribution FactorsDr. Amarjeet Singh
In order to design and implement preventive
and remedial actions, a continuous performance of fast
security analysis is imperative amid outages of system
components. Following the contingency of a system
component, State estimation and Load flow techniques
are the two popular techniques used to determine
system state variables leading to estimation of flows,
losses and violations in nodal voltages and transmission
line flows. But the dynamic state and complexity of the
system requires faster means of estimations which can
be achieved by linear distribution factors. The use of
Distribution factors in form of Power Transfer
Distribution Factors (PTDF) and Line Outage
Distribution Factors (LODF) which are transmission
line sensitivities with respect to active power exchanges
between buses and transmission line outages offer an
alternative to these two techniques being linear,
quicker, and non-iterative. Following the estimation of
the linear distribution factors from a reference
operating point (base case) and contingency cases
involving line outage, generator output variation and
outage of a Six bus network using Matlab programs,
the results show that by means of Linear Distribution
factors quick estimates of post outage line flows can be
made which match flow results obtained from DC load
flow analysis.
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An Approach for Power Flow Analysis of Radial Distribution Networksresearchinventy
This paper provides an easy and effective approach to the load flow solution of Radial distribution networks. As compared to the various methods proposed in the past, this work presents a new technique consisting of load flow solution of the network, facilitated by the identification of all the nodes beyond a particular branch. The proposed method is quite accurate and reliable for the system having any number of nodes. The primary target of this work is to evaluate the results with high precision and convergence.
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.
Development of Advanced Unbalanced Power Converter for AC DC Power Distributi...ijtsrd
With the rapid demand of electricity, the installation of power electronics based equipment in power distribution system has grown rapidly for ac dc system coupling, system protection, alternative energy source interface, etc. This paper focus on power electronic component and system modelling techniques and three phase ac dc power flow analysis for power distribution systems. The research discusses the models that are developed for unbalanced power electronic converters, such as thyristor converters, diode rectifiers, and Pulse Width Modulated PWM converters. The modelling approach captures the imbalance of distribution systems using three, delta connected, single phase converters. To perform system analysis, these models have been incorporated into two types of ac dc power flow solvers A three phase backwards forward sequential solver and a three phase unified solver using the modified nodal analysis method. Both solvers have been applied to unbalanced radial and weakly meshed distribution systems. Finally, an ac dc system hardware test bed was created to validate the proposed models and the performance of the power flow solvers. Extensive hardware tests, time domain simulations, and steady state analysis have been performed. Mr. Toseef Ahmad | Mr. Suraj Kumhar | Mr. Deepak Joshi "Development of Advanced Unbalanced Power Converter for AC-DC Power Distribution System" 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/ijtsrd47775.pdf Paper URL: https://www.ijtsrd.com/engineering/electrical-engineering/47775/development-of-advanced-unbalanced-power-converter-for-acdc-power-distribution-system/mr-toseef-ahmad
ASSESSMENT OF VOLTAGE FLUCTUATION AND REACTIVE POWER CONTROL WITH SVC USING PSOKashif Mehmood
Smart grid novel growth in the arena of power, this is a new scheme and apparatus for producing and distributing
electricity. Smart grids are very important part of the electrical circuit. Distribution Management System (DMS) used by the utilities for the
state Estimation (SE). Basic application distribution control system, evaluation (SE) and the control reactive power). There SE principally
used to monitor and to control the entire distributed network. In the distribution network has a problem voltage profile. It is controlled by
distributed generators (DG), which are located in diverse positions in the system to maintain the voltage within certain limits. Validation
through the implementation on the IEEE 14-bus radial transmission system indicated that PSO is reasonable to achieve the
task. MATLAB software is used for results simulation
OPTIMIZATION OF A TWO-HOP NETWORK WITH ENERGY CONFERENCING RELAYSijwmn
This paper considers a two-hop network consisting of a source, two parallel half-duplex relay nodes, and
two destinations. While the destinations have an adequate power supply, the source and relay nodes
rely on harvested energy for data transmission. Different from all existing works, the two relay nodes
can also transfer their harvested energy to each other. For such a system, an optimization problem is
formulated with the objective of maximizing the total data rate and conserving the source and relays
transmission energy, where any extra energy saved in the current transmission cycle can be used in
the next cycle. It turns out that the optimal solutions for this problem can be either found in a closedform
or through one-dimensional searches, depending on the scenario. Simulation results based on both
the average data rate and the outage probability show that energy cooperation between the two relays
consistently improves the system performance.
Transmission Loss Allocation Based on Lines Current FlowIJAPEJOURNAL
In this paper, the transmission loss allocation problem has been studied and a new method for loss allocation in pool electricity markets has been proposed. To do that, at first using a transmission line loss equations respect to bus injected currents, the share of each bus from the mentioned transmission line losses has been determined. Then, this method has been applied to the total network transmission lines and the share of each bus from the total losses has been acquired. The proposed method is based on the main network relations and no any simplifying suppose has been used. Finally, the proposed method is studied on a typical network.
Optimal siting and sizing of unified power flow controller using sensitivity...IJECEIAES
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A Novel Approach for Allocation of Optimal Capacitor and Distributed Generati...paperpublications3
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Analysis of the Use of Universal Distribution Factors in SEC Power Grid
1. Research Inventy: International Journal of Engineering And Science
Vol.6, Issue 4 (April 2016), PP -58-64
Issn (e): 2278-4721, Issn (p):2319-6483, www.researchinventy.com
58
Analysis of the Use of Universal Distribution Factors in SEC
Power Grid
A. Alodhaiani 1,*
, Y. Alturki 2
, M. El-Kady 2
1
Saudi Electricity Company (SEC), Riyadh, Saudi Arabia
2
Department of Electrical Engineering, SEC Chair for Reliability and Security, King Saud University, Riyadh,
Saudi Arabia
Abstract: Distribution factors have been extensively used in many power system analysis and planning studies.
In recent power system studies, the AC distribution factors are insensitive to the operating point and relatively
sensitive at certain degree to changes in network topology. These factors are linear approximations of
sensitivities of variables with various inputs. This paper presents the calculation of the universal distribution
factors (UDF’s) applies them on several practical scenarios of Saudi Electricity Company (SEC) power grid.
The results are analyzed and evaluated considering various system conditions of SEC load. The results show
that the accuracy of the used approach is acceptable compared with exact method. This is practically beneficial
to SEC in computing its grid complex power flows using UDF's at the base case without the need to recalculate
UDF’s which save efforts and time.
Key words: Distribution Factors, Sensitivity Factors,Power System, Electricity Market.
I. Introduction
AC distribution factors and its application play an important role in operation and control of power
systems and have been addressed extensively in the literature. In this respect, considerable research efforts have
been expended during recent years and it’s going on in developing theories, new techniques, policies and
required criteria for distribution factors and its application in operation and control of power system. A novel
model for evaluating universal distribution factors that is suitable for an extensive range of power system
pricing studies and power system planning and analysis were introduced in [1]. The author present the
computation of the universal distribution factors in addition to their sensitivities in with respect to the voltage
profile of line. The availability and utilization of the existing transmission systems and the operation of the
competitive markets in electricity system are very much affected by the congestion. The distribution factors are
linear approximations of sensitivities of variables with respect to various inputs and are computed for a specified
network topology and parameter values. Hence, they are very important in designing the congestion model for
various market applications. The authors in reference [2] investigated the analytical characteristics, the
robustness and the quality of the approximations provided the power transfer distribution factors (PTDFs).
These factors have provided a reliable approximation for large power system networks. The errors of the
approximations are within the permissible for a broad range of conditions including contingencies.The concepts
and the development of the AC distribution factors in power systems has been addressed in the literature [3-5].
In this regard, the authors of reference [3] presented a solution algorithm to improve the poor accuracy of
generalized generation shift distribution factor (GGDF). A modified power transfer distribution factor (MPTDF)
was used to consider the nonconformity of the demand change. When the system operating point is shifted to a
new one, the power flows in the line can be got directly without running a load flow program. By means of four
example systems, the potential behavior of the proposed method was demonstrated with very fast execution time
and with high accuracy compared with the fast-decoupled load flow (FDLF) technique. On the other hand, the
authors of reference [4] has analyzed the distribution of source power from the energy source, by deriving and
defining the complex power dynamics distribution factors based on the circuit theory. The form of these factors
shows that the power distribution is not only related to the network topology and circuit parameters, but also
related to the dynamic state of the system. The source powers are linear distribution in the network according to
these factors and whereas the branch flows and losses in the network are different forms of source powers. The
example demonstrated that the results calculated by proposed method are unique and they satisfy complex
power conservation. By using the Distribution factors, the contributions of the transmission users towards line
flows in an electricity market are identified and the transmission charges are fairly fixed. However, due to some
limitations, the Distribution factors cannot be applied for the wider applications of electricity market practices.
In reference [5], a new technique was proposed to evaluate the transmission line flows more accurately. The
new justified distribution factors approach has shown better result than other commonly used distribution factors
when tested in a realistic electricity.
2. Analysis of the Use of Universal Distribution…
59
Power transfer distribution factors depend on the operating point and topology of an electric power system.
However, in recent researches, the power transfer distribution factors were shown theoretically to be relatively
insensitive to the operating point. The authors of reference [6] provided empirical corroboration of this
theoretical result. The several researches and test conducted on the three principal interconnections namely in
North America, the Eastern interconnection, the Western interconnection, and the Electric Reliability Council of
Texas (ERCOT) interconnection has shown consistent observations. On the other hand, the authors of reference
[7], have studied the Power Transfer Distribution Factors (PTDF) and the underlying flow-based model
proposed for capacity determination and allocation in electricity grids. Several factors such as topological and
seasonal changes as well as zone building which influence PTDF coefficients are critically analyzed through AC
power flow simulation of the Union for the Co-ordination of Transmission of Electricity (UCTE) transmission
network (transmission system operators in continental Europe). Finding of border capacities are also analyzed.
Also, the author of reference [8] proposed a methodology to create a family of zonal Power Transfer
Distribution Factor (PTDF) matrices which can be used to find the power flows accurately for the Zonal market
under dynamic condition. Introduction of data mining methods for selected typical hours based on area balance
and PTDF matrices of these typical hours calculated to form a family are tested on the New England system. It
is observed that the error, when using a family of PTDF matrices for estimating cross-border power flows in a
zonal market model is very much less than the method of using only one PTDF matrix.
A model for calculatingdistribution factorswere applied on a several scenarios of SEC power grid in this
paper. We analyzed the calculationof UDF’s on the SEC grid at all scenarios consideringvarious percentages of
the SEC load. Theevaluation of the UDF’s with respect the operating point and network topology were
alsodiscussed.
II. Universal Distribution Factors (UDF’s)
1.1. UDF’s formula
𝑁𝑏 = 𝑁 + 𝑁𝑑 where,𝑁𝑏 is the number of the buses in the power system with N and 𝑁𝑑 is the number of the
generation buses and load busesin the power systemrespectively. Also, 𝑁 𝑚 is the number of the transmission
branches. We can calculate line complex power flows (𝑆𝑝𝑞 ) between bus 𝑝 and bus 𝑞from follow equation;
𝑆𝑝𝑞
∗
= 𝑉𝑝
∗
𝐼𝑝𝑞 (1)
Where𝑆𝑝𝑞 , 𝑉𝑝 and 𝐼𝑝𝑞 denote theline complex power flows of 𝑝𝑞line at bus 𝑝, voltage at node 𝑝, and 𝑝= 1, 2, …
, 𝑁 and current in line 𝑝𝑞, respectively.
The complex power flow between buses 𝑝 and 𝑝on line 𝑚can be expressed as;
𝑆𝑝
∗
= 𝑙 𝑉𝑝
∗
+ 1 − 𝑙 𝑉𝑞
∗
𝐼 𝑚 = 𝜑 𝑚 𝐼 𝑚 (2)
Where 𝑙denote the location on line 𝑚at which𝑆 𝑚 is evaluated. For illustration, if 𝑙 = 0this illustrate that𝑆 𝑚 is
evaluated at bus 𝑞, if 𝑙 = 1this illustrate that 𝑆 𝑚 is evaluated at bus 𝑝 and if 𝑙 = 0.5this illustrate that 𝑆 𝑚 is
evaluated at the mid-point on line 𝑚, that is;
𝑆𝑝
∗
= 𝑉𝑝
∗
+ 𝑉𝑞
∗
/2 𝐼 𝑚 (3)
Where; 𝐼 𝑚 is the current on line m.
The bus admittance matrix 𝑌 of the grid can be determined as follow;
𝑉 = 𝑍𝐼 or 𝑉 = 𝑌−1
𝐼 (4)
Diagonal matrix 𝜑 can be written as;
𝜑 𝑚 = 𝑑𝑖𝑎𝑔𝑜𝑛𝑎𝑙 𝜑1, 𝜑2, … , 𝜑 𝑛𝑚
The 𝑛 𝑚 -vector of complex conjugate linepowers can be written as follows;
𝑆 𝑚
∗
= 𝜑 𝑚 𝐼 𝑚 (5)
Where 𝑆 𝑚
∗
and 𝐼 𝑚 denotes the 𝑛 𝑚 vector of complex conjugate linepowers {𝑆 𝑚 } and 𝑛 𝑚 vector of complex line
currents {𝐼 𝑚 }, respectively.
The bus incidence matrix that is A branch-to-node incidence matrix where 𝐴 = ( 𝑛 𝑚 × 𝑛 𝑏 ), which consist of
one row for each branch and one column for each bus with an entry 0, 1 or -1. Where,𝐴 𝑏𝑚 = 0 if the branch 𝑚
is not connected to the bus 𝑏, 𝐴 𝑏𝑚 = −1 if the current in branch 𝑚 is directed toward bus 𝑏 and𝐴 𝑏𝑚 = 1if the
current in branch 𝑚 is directed away from bus 𝑏.
Therefore;
3. Analysis of the Use of Universal Distribution…
60
𝑉𝑚 = 𝐴 𝑉 (6)
Hence,
𝐼 𝑚 = 𝑌 𝑃
𝑉𝑚 = 𝑌 𝑃
𝐴 ( 𝑌−1
𝐼 ) (7)
Where, 𝑌 𝑃
primitive admittance matrix of two coupled branches. The diagonal elements of the primitive
admittance matrix represent line self-admittances and off-diagonal elements represent mutual line admittances.
Hence;
𝜑 𝑚 𝐼 𝑚 = 𝜑 𝑚 𝑌 𝑃
𝐴 𝑌−1
𝐼 (8)
The bus voltage matrix can be written as;
𝐸 = 𝑑𝑖𝑎𝑔𝑜𝑛𝑎𝑙 𝑉1, 𝑉2, … , 𝑉𝑛
Where 𝐸 is the diagonal matrix of bus voltages. The n-vector 𝑆∗
of complex conjugate bus powers can be written
as follows;
𝑆∗
= 𝐸∗
𝐼 (9)
or
𝐼 = 𝐸∗−1
𝑆∗
(10)
Therefore;
𝑆 𝑚
∗
= 𝜑 𝑚 𝐼 𝑚 = [ 𝜑 𝑇 𝑌 𝑃
𝐴 𝑌−1
) 𝐸∗ −1
𝑆∗
= 𝑈𝐷𝐹 𝑆∗
(11)
The universal distribution factors matrix 𝑈𝐷𝐹 relates line complex power flows 𝑆 𝑚 to the bus injected complex
powers𝑆𝑏 , with 𝑛 𝑏 and 𝑛 𝑚 denoting, respectively, number of buses and number of lines in the system, as
follows;
𝑆 𝑚 = 𝑈𝐷𝐹 𝑆 (12)
Where is the universal distribution factors matrix UDF is;
𝑈𝐷𝐹 = 𝜑 𝑚
∗
𝑌 𝑃∗
𝐴 𝑌∗−1
𝐸−1
(13)
1.2. UDF’s Evaluation
To evaluate the validity and the effectiveness of the computedUDF’s, the system is analyzed and studied with
applying a number of scenarios. These scenarios includes a change demands and generation. Line complex
power flows are calculated as in equation (14) in different scenarios.
𝑃𝐿 𝑛𝑒𝑤 = 𝑈𝐷𝐹 𝑃𝐵 𝑛𝑒𝑤 (14)
Where 𝑷 𝑳 𝒏𝒆𝒘 is the new line complex power flow after change the bus injected power (𝑷 𝑩 𝒏𝒆𝒘),
𝑃𝐿 𝑛𝑒𝑤 = 𝑃𝐿0
+ ∆𝑃𝐿 (15)
and
𝑃𝐵 𝑛𝑒𝑤 = 𝑃𝐵0
+ ∆𝑃𝐵 (16)
Which ∆𝑃𝐿 and ∆𝑃𝐵denotes the changes in the lines complex power flows and the changes in bus injected
powers respectively.
II. Case Studies
In this section, the universal distribution factors (UDF’s) model proposed in [1] is applied onthe 2012 real
system of Saudi Electricity Company (SEC). SEC grid consists of 2592 buses, 711 generation units, 2251
transmission lines, 1898 transformers, 35 line shunts, 248 switched shunts and 139 tie-lines. Figure 1 shows the
consumption of electricity in Kingdom of Saudi Arabia (KSA) which is totally covered by SEC interconnected
network (generation, transmission and distribution). The electricity peak load of KSA in SEC power grid
happened during the summer season at48138 MW which was recorded in 21 July 2012.
4. Analysis of the Use of Universal Distribution…
61
Fig. 1 Consumption of the electricity in KSA
The real system of Saudi Electricity Companygrid is reduced to 15 tie lines and9 buses as shown in Figure 2.
The9 buses of the reducedmodel denotes four generations owned by SEC, four load areas and one independent
power plantowned by Dhurma Electricity Company. Thefour load areas represents central operating area
(COA),west operating area (WOA), east operating area (EOA) and the south operating are (SOA).The 15 tie
lines representthe corridorsconnected all loads and generators. The UDF’s have been determined taking in to
account all the several scenarios applied on the reduced model of real SEC system.
Fig. 2Reduced model of SEC interconnected system
The UDF’s are calculated at the base case, which is the solved base case of 2012 SEC network.Threepractical
simulated scenarios were conducted to examine the validity and accuracy of using the universal distribution
factors of the base case when operating points and network topologies of SEC electric power system change.
The results are analyzed and discussed.
Table 1shows the details of the three scenarios that have been conducted to evaluate the application of universal
distribution factors on SEC network.
Table 1. Details of the simulated scenarıos for the UDF’s evaluatıons
Scenarıo no. Scenarıo Descrıptıon
Base case Solved base case of 2012 with no contingencies
Scenario no. 1
10% lossof generation owned by SEC generation
Company SEC – GEN (D) bus No.811330
Scenario no. 2 10% Increase of demand WOA bus#820001
Scenario no. 3
25% Outage of line between SEC-GEN (A) bus
No.820002 and COA demand bus No. 818003
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
50,000
KSA2012Load(MW)
Time (Hours)
2012 KSA Load Duration Curve (Hourly)
48,138 MW, 21/07/2012
1 1000 2000 3000 4000 5000 6000 7000 8000 8784
5. Analysis of the Use of Universal Distribution…
62
IV. Results and Discussion
4.1 UDF’s analysis at base case
The universal distribution factors matrix isdetermined at the base case with no contingency cases at parameter 𝒍
= 0.5 (𝑺 𝒎 is evaluated based on voltages at the mid-point of line m). The calculated universal distribution
factors of all reduced network lines are shown in Table 2.
From line no. 1 in Table 2, it is interesting to notice that the bus no. 811357 has the largest DF value in this line,
while the other buses have less influence on this line. In other words, bus 811357 is generation bus and the
amount of the transmitted power through this line is very high. DF’s values of the buses 844004, 830001 and
840011 are much smaller than the rest of the buses, which indicates that the amount of power injection or
withdrawal change in these buses have less influence on the tie-line no. 1 compared with the other buses. From
line no. 12 in Table 2, we notice that the bus no. 813257 has DF value while the other buses do not have DF
values because of this bus is connected only to one bus in the reduced network and the number of this bus is
818003. The rest lines have the same properties as line no.1.
The UDF’s matrix can be used to measure the sensitivity of the power flow to the power variation from the buses.
Therefore, we can utilize the UDF’s matrix to indicate the load demand in the system. The real and imaginary values of the
computed UDF’s have positive and negative values as indicated in Appendix A. These values are leading us to two points,
the first one is; if the UDF’s values positive, then the power flow on the corresponding branch is decreasing, and the second
point is; if the UDF’s values negative, then the power flow on the corresponding branch is increasing.
4.2 UDF’s evaluation at all scenarios
The line power flows have been determined by using one universal distribution factors matrix calculated at the
base case. These line power flows have been calculated at all the scenarios as shown in Table 3 considering
contingency cases as represented in Table 1 and using the UDF’s at the base case. The calculatedline power
flows are compared with the exact line MVA power flows obtained by AC power flow at each line. Table
3shows the error values between the exact and computed line MVA power flows at all scenarios.
6. Analysis of the Use of Universal Distribution…
63
Results showthat the absolute value of error percentages between exact and calculated line power flows for
all the network lines at scenarios no. 1 and 2 are small and negligible. It is observed that the error values for
scenario no. 1 and 2 ranges from 0% to 2.7%. Therefore, the computed UDF’s at the base case can be used on
SEC network to calculate the line complex power flows for all the network lines. It can be concluded that when
system load increases up to 10% or the network generation decreases to the percentage of 10% reduction, SEC
can use UDF’s of the base case with acceptable accuracy. This is useful to SEC as it saves time and effort by
avoiding calculating UDF’s and AC powers flows for network changes with these ranges.
On the other hand, simulated results show that the absolute value of error percentages for all the network
lines at scenario no.3 are slightly high for some lines and almost areequal to the percentage of the corridors
outages for some lines.The error values of this scenario ranges from 0% to about 10% for all lines except for
line 11 at which the error reaches 19.36%. . Therefore, the computed UDF’s at the base case can be used at
certain degree on SEC network to calculate the line complex power flows for some of the network lines, which
gives reasonable results except on line no. 11.
It is worth noticing that error percentages for scenarios 1 and 2 are much lower than those of scenario 3. So,
one can conclude that change of network topology may lead to moreeffect on UDF’s resulting in much higher
errors than the situation when the change is in system load or generation.. The universal distribution factors are
more sensitive at certain degree to the network topology than to the operating point.
V. Conclusion
This paper presented the universal distribution factors UDF’s and it applied them on different practical scenarios
on SEC power grid. The evaluation of the UDF’s on SEC network considering several scenarios including
different variations of the demands as well as changes in network topology conducted but due to limited space
three scenarios were presented. The UDF's at base case can only be usedon a changed network if the difference
between their results and the actual calculated line power flows of the new changed network is negligible (i.e.
acceptable error), otherwise, UDF's should be recalculated.
In this paper, three scenarios including generation and system demands changes as well as outage of a tie-line
of SEC power grid were simulated. Comparison of simulated results between exact and calculated line power
flows for all the network lines shows that the absolute value of the error percentages are acceptable for demand
or generation changes as represented in Table. 1. While for system topology change such as line outage,the
errors are slightly high for some lines and almost equal to the percentage of the corridors for some lines.In
conclusion, the calculated UDF’s at the base case of SEC grid can be used to calculate the line power flows for
all the network lines in several expected and critical scenarios of the SEC power network with acceptable
accuracy. This is beneficial to SEC operation as it saves time and effort on real time when such contingencies
occur on its real network.
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64
VI. Acknowledgment
This work was supported by Saudi Electricity Company (SEC) through its Chair in Power System Reliability
and Security at Department of Electrical Engineering, King Saud University.
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