This paper explores the interconnection of large scale Photo-Voltaic (PV) systems to the grid though a High Voltage Direct Current (HVDC) link. HVDC link is recently utilized for transmission lines longer than 50 km. It is usually utilized to interconnect two asynchronous grids with the same or different frequencies while avoiding stability disturbances greatly. A suitable Maximum Power Point Tracking (MPPT) techniques is employed to control the performance of the integrated PV system. The system of the HVDC link has two 12-pulse converter using thyristor-bridges. The delay and the extinction angles at the rectifier and the inverter units control the flow and the quantity of the transmitted power from the PV system into the grid. Fixed capacitors and filters are used to provide the AC side with the required reactive power and reduce the harmonic contents. For evaluation purposes, different simulation investigations are carried out with a detailed modeling using the MATLAB. These tests corroborate the efficacy of HVDC link for integrating large PV systems to electrical grids
A Power quality problem is an occurrence of nonstandard voltage, current or frequency that results in a
failure or a misoperation of end user equipments. Utility distribution networks, sensitive industrial loads and
critical commercial operations suffer from various types of outages and service interruptions which can cost
significant financial losses. With the increase in load demand, the Renewable Energy Sources (RES) are
increasingly connected in the distribution systems which utilizes power electronic Converters/Inverters. This
paper presents a single-stage, three-phase grid connected solar photovoltaic (SPV) system. The proposed system
is dual purpose, as it not only feeds extracted solar energy into the grid but it also helps in improving power
quality in the distribution system. The presented system serves the purpose of maximum power point tracking
(MPPT), feeding SPV energy to the grid, harmonics mitigation of loads connected at point of common coupling
(PCC) and balancing the grid currents. The SPV system uses a three-phase voltage source converter (VSC) for
performing all these functions. An improved linear sinusoidal tracer (ILST)-based control algorithm is proposed
for control of VSC. In the proposed system, a variable dc link voltage is used for MPPT. An instantaneous
compensation technique is used incorporating changes in PV power for fast dynamic response. The SPV system
is first simulated in MATLAB along with Simulink and simpower system toolboxes.
Open-Switch Fault-Tolerant Control of Power Converters in a Grid-Connected Ph...IAES-IJPEDS
This paper presents the study of an open switch fault tolerant control of a
grid-connected photovoltaic system. The studied system is based on the
classical DC-DC boost converter and a bidirectional 6-pulse DC-AC
converter. The objective is to provide an open-switch fault detection method
and fault-tolerant control for both of boost converter and grid-side converter
(GSC) in a grid-connected photovoltaic system. A fast fault detection method
and a reliable fault-tolerant topology are required to ensure continuity of
service, and achieve a faster corrective maintenance. In this work, the mean
value of the error voltages is used as fault indicator for the GSC, while, for
the boost converter the inductor current form is used as fault indicator. The
fault-tolerant topology was achieved by adding one redundant switch to the
boost converter, and by adding one redundant leg to the GSC. The results of
the fault tolerant control are presented and discussed to validate the proposed
approach under different scenarios and different solar irradiances.
Design of a hybrid power system for a low dc voltage distribution system suit...Itai Hamunakwadi
Abstract—This paper focuses on the design of a hybrid power
system based on renewable energy sources for Low Voltage
Distribution system suitable for remote areas. Rural
electrification has been a challenging issue for many third world
countries. The available national voltage distribution systems are
only limited to areas with good road networks. Consequently, this
means rural and remote areas with poor road networks are
isolated from the national grid. Research is to be conducted so as
to design a feasible islanded power system that can furnish
adequate power to such areas.
Operation and Control of Grid Connected Hybrid AC/DC Microgrid using Various RESIAES-IJPEDS
This paper proposes a Hybrid AC/DC Microgrid in alliance with Photo Voltaic (PV) energy, Wind Energy and Proton Exchange Membrane (PEM) Fuel cells. Microgrids are becoming increasingly attractive to the researchers because of the less greenhouse gases, low running cost, and flexibility to operate in connection with utility grid. The Hybrid AC/DC Microgrid constitutes independent AC and DC subgrids, where all the corresponding sources and loads are connected to their respective buses and these buses are interfaced using an interfacing converter. The Hybrid AC/DC Microgrid increases system efficiency by reducing the multiple reverse conversions involved in conventional RES integration to grid. A Small Hybrid AC/DC Microgrid in grid connected mode was modeled and simulated in MATLAB- SIMULINK environment. The simulation results prove the stable operation considering the uncertainty of generations and loads.
There is need for an energy storage device capable of transferring high power in transient situations
aboard naval vessels. Currently, batteries are used to accomplish this task, but previous research has
shown that when utilized at high power rates, these devices deteriorate over time causing a loss in lifespan.
It has been shown that a hybrid energy storage configuration is capable of meeting such a demand while
reducing the strain placed on individual components. While designing a custom converter capable of
controlling the power to and from a battery would be ideal for this application, it can be costly to develop
when compared to purchasing commercially available products. Commercially available products offer
limited controllability in exchange for their proven performance and lower cost point - often times only
allowing a system level control input without any way to interface with low level controls that are
frequently used in controller design. This paper proposes the use of fuzzy logic control in order to provide
a system level control to the converters responsible for limiting power to and from the battery. A system
will be described mathematically, modeled in MATLAB/Simulink, and a fuzzy logic controller will be
compared with a typical controller.
A Power quality problem is an occurrence of nonstandard voltage, current or frequency that results in a
failure or a misoperation of end user equipments. Utility distribution networks, sensitive industrial loads and
critical commercial operations suffer from various types of outages and service interruptions which can cost
significant financial losses. With the increase in load demand, the Renewable Energy Sources (RES) are
increasingly connected in the distribution systems which utilizes power electronic Converters/Inverters. This
paper presents a single-stage, three-phase grid connected solar photovoltaic (SPV) system. The proposed system
is dual purpose, as it not only feeds extracted solar energy into the grid but it also helps in improving power
quality in the distribution system. The presented system serves the purpose of maximum power point tracking
(MPPT), feeding SPV energy to the grid, harmonics mitigation of loads connected at point of common coupling
(PCC) and balancing the grid currents. The SPV system uses a three-phase voltage source converter (VSC) for
performing all these functions. An improved linear sinusoidal tracer (ILST)-based control algorithm is proposed
for control of VSC. In the proposed system, a variable dc link voltage is used for MPPT. An instantaneous
compensation technique is used incorporating changes in PV power for fast dynamic response. The SPV system
is first simulated in MATLAB along with Simulink and simpower system toolboxes.
Open-Switch Fault-Tolerant Control of Power Converters in a Grid-Connected Ph...IAES-IJPEDS
This paper presents the study of an open switch fault tolerant control of a
grid-connected photovoltaic system. The studied system is based on the
classical DC-DC boost converter and a bidirectional 6-pulse DC-AC
converter. The objective is to provide an open-switch fault detection method
and fault-tolerant control for both of boost converter and grid-side converter
(GSC) in a grid-connected photovoltaic system. A fast fault detection method
and a reliable fault-tolerant topology are required to ensure continuity of
service, and achieve a faster corrective maintenance. In this work, the mean
value of the error voltages is used as fault indicator for the GSC, while, for
the boost converter the inductor current form is used as fault indicator. The
fault-tolerant topology was achieved by adding one redundant switch to the
boost converter, and by adding one redundant leg to the GSC. The results of
the fault tolerant control are presented and discussed to validate the proposed
approach under different scenarios and different solar irradiances.
Design of a hybrid power system for a low dc voltage distribution system suit...Itai Hamunakwadi
Abstract—This paper focuses on the design of a hybrid power
system based on renewable energy sources for Low Voltage
Distribution system suitable for remote areas. Rural
electrification has been a challenging issue for many third world
countries. The available national voltage distribution systems are
only limited to areas with good road networks. Consequently, this
means rural and remote areas with poor road networks are
isolated from the national grid. Research is to be conducted so as
to design a feasible islanded power system that can furnish
adequate power to such areas.
Operation and Control of Grid Connected Hybrid AC/DC Microgrid using Various RESIAES-IJPEDS
This paper proposes a Hybrid AC/DC Microgrid in alliance with Photo Voltaic (PV) energy, Wind Energy and Proton Exchange Membrane (PEM) Fuel cells. Microgrids are becoming increasingly attractive to the researchers because of the less greenhouse gases, low running cost, and flexibility to operate in connection with utility grid. The Hybrid AC/DC Microgrid constitutes independent AC and DC subgrids, where all the corresponding sources and loads are connected to their respective buses and these buses are interfaced using an interfacing converter. The Hybrid AC/DC Microgrid increases system efficiency by reducing the multiple reverse conversions involved in conventional RES integration to grid. A Small Hybrid AC/DC Microgrid in grid connected mode was modeled and simulated in MATLAB- SIMULINK environment. The simulation results prove the stable operation considering the uncertainty of generations and loads.
There is need for an energy storage device capable of transferring high power in transient situations
aboard naval vessels. Currently, batteries are used to accomplish this task, but previous research has
shown that when utilized at high power rates, these devices deteriorate over time causing a loss in lifespan.
It has been shown that a hybrid energy storage configuration is capable of meeting such a demand while
reducing the strain placed on individual components. While designing a custom converter capable of
controlling the power to and from a battery would be ideal for this application, it can be costly to develop
when compared to purchasing commercially available products. Commercially available products offer
limited controllability in exchange for their proven performance and lower cost point - often times only
allowing a system level control input without any way to interface with low level controls that are
frequently used in controller design. This paper proposes the use of fuzzy logic control in order to provide
a system level control to the converters responsible for limiting power to and from the battery. A system
will be described mathematically, modeled in MATLAB/Simulink, and a fuzzy logic controller will be
compared with a typical controller.
Restoration plans are guidelines for system operators to use during blackout and blackstart events. However, many utilities face several challenges to their restoration plans including generation retirements affecting the availability of next-start generators and steep increasing levels of renewable generation. This paper addresses the two challenges highlighted by dynamically assessing one of Dominion Energy’s blackstart cranking paths and studying the impact of photovoltaic (PV) generation during restoration events. Potentially useful PV inverter control schemes are identified and studied to aid the restoration process. One of the blackstart cranking paths that is currently in Dominion Energy’s system restoration plan is studied using PSSE. A 20 MW capacity PV farm located on the path is used to study the impact of PV considering no control scheme, a voltage control scheme, and two active power control techniques: curtailment-based or battery storage. The voltage control scheme is found to successfully mitigate over-voltage from energizing long and extra-high voltage lines. Both active power control techniques improve the frequency nadir although, operational and implementation challenges have been identified for these schemes.
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.
07 22 sep15 8711 18507-2-sm -edit_FACT Device for Reactive Power Compensation...IJPEDS-IAES
In the deregulating electricity market, many private sector power producers
are participating actively. With growing number of the wind mills and solar
power generation, the reactive power production will be more because of
induction generator and inductive type load. Many blackouts have happened
in the past decades due to more reactive power which lead to a decrease in
the magnitude of real power. It is very essential to compensate the reactive
power, increase the real power flow in the transmission line, increase the
transmission efficiency, improve the system stability and be in a safer place
to save the fossil fuels for the future. In this paper the importance of reactive
power and its various compensation techniques are applied to a five bus
deregulated test case modeled and analyzed. The simulations were done
using Matlab Simulink, for various FACT controllers such as STATCOM,
SVC, SSSC and UPFC compensation and the results were tabulated and
compared.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
A Review on Design and Development of high Reliable Hybrid Energy Systems wit...IJPEDS-IAES
Hybrid Energy system is a combination of two or more different types of energy resources. Now a day this hybrid energy system plays key role in various remote area power applications. Hybrid energy system is more reliable than single energy system. This paper deals with high reliable hybrid energy system with solar, wind and micro hydro resources. The proposed hybrid system cable of multi mode operation and high reliable due to non communicated based controllers (Droop Characteristic Control) are used for optimal power sharing. Size of battery can be reduced because hydro used as back up source and Maximum power point Tracking also applied to solar and wind energy systems.
Modeling, Control and Power Management Strategy of a Grid connected Hybrid En...IJECEIAES
This paper presents the detailed modeling of various components of a grid connected hybrid energy system (HES) consisting of a photovoltaic (PV) system, a solid oxide fuel cell (SOFC), an electrolyzer and a hydrogen storage tank with a power flow controller. Also, a valve controlled by the proposed controller decides how much amount of fuel is consumed by fuel cell according to the load demand. In this paper fuel cell is used instead of battery bank because fuel cell is free from pollution. The control and power management strategies are also developed. When the PV power is sufficient then it can fulfill the load demand as well as feeds the extra power to the electrolyzer. By using the electrolyzer, the hydrogen is generated from the water and stored in storage tank and this hydrogen act as a fuel to SOFC. If the availability of the power from the PV system cannot fulfill the load demand, then the fuel cell fulfills the required load demand. The SOFC takes required amount of hydrogen as fuel, which is controlled by the PID controller through a valve. Effectiveness of this technology is verified by the help of computer simulations in MATLAB/SIMULINK environment under various loading conditions and promising results are obtained.
A CONTROL APPROACH FOR GRID INTERFACING INVERTER IN 3 PHASE 4 WIRE DISTRIBUT...IJMER
With the increase in load demand, the Renewable Energy Sources (RES) are
increasingly connected in the distribution systems which utilizes power electronic
Converters/Inverters. Nowadays, 3-phase 4-wire distribution power system has been widely used in
residential and office buildings, manufacturing facilities, schools etc This paper presents a novel
control strategy for achieving maximum benefits from the grid-interfacing inverters when installed in
3-phase 4-wire distribution systems. The inverter can thus be utilized as: 1) power converter to inject
power to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics and
load neutral current. All of these functions may be accomplished either individually or
simultaneously. This new control concept is demonstrated with extensive MATLAB/Simulink
simulation studies
A Novel Technique for Enhancing Active and Reactive Power Quality for Renewab...IJMER
Renewable energy resources (RES) are being increasingly connected in distribution systems utilizing power electronic converters. This paper presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to inject power generated from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies and results.
A Flexible AC Distribution System for a Microgrid with a Photovoltaic System ...IJMTST Journal
This paper presents a FACT ac distribution system device for micro grid applications. The device aims to improve the power quality and reliability of the overall power distribution system that the micro grid is connected to. The control design employs a new model predictive control algorithm which allows faster computational time for large power systems by optimizing the steady-state and the transient control problems separately. Extended Kalman filters are also employed for frequency tracking and to extract the harmonic spectra of the grid voltage and the load currents in the micro grid. Simulation results is verified through different case studies.
Mitigation of Voltage Fluctuations in Power System Using STATCOMIJERA Editor
Wind energy being a renewable source of energy is enjoying a rapid growth globally. However, wind energy being an uncontrollable source of energy coupled with the fact that it uses distributed induction generators for power conversion poses a challenge in integrating a large scale wind-farm into a weak power system. An actual weak power system with two large Wind-Farms (WFs) coupled to it is introduced as part of this study. A model of this integrated system along with a STATCOM for steady state and dynamic impact study is developed in the MATLAB/Simulink environment. The power quality issues are highlighted and a centralized STATCOM is proposed to solve the issue of the voltage fluctuations in particular in addition to addressing the other issues. Based on the results obtained from the simulation, the system voltage control issues are analyzed and the location of STATCOM is assessed. Finally, a STATCOM control strategy for suppression of voltage fluctuations is presented.
Human population of the world and its Electrical
power demand is increasing day by day. The available fossil
fuel energy resources are being depleted day by day. So it is a
wise decision to absorb the natural renewable energy
resources. Among the other natural resources, solar energy is
also a precious available energy source. In Pakistan abundance
solar energy can be easily extracted.
In this research work, impacts of solar generation system are
analyzed while integrated with 11kV radial distribution feeder.
PV system is integrated with feeder in three different ways by
using SINCAL software and its impacts in terms of the power
loss, voltage profile and short circuit level are analyzed. When
PV system is integrated with HT side it results negligible
increment in voltage, no change in LT losses, negligible
decrement in HT losses and no change in short circuit level.
When PV system is connected with LT bus-bar of each
transformer, there is significant increment in voltage, small
decrement in LT losses, significant decrement in HT losses and
smaller increment in short circuit level. When PV system is
connected with each load, there is significant increment in
voltage, large decrement in LT losses, significant decrement in
HT losses and smaller increment in short circuit level.
Isolated Wind Hydro Hybrid Generation System with Battery StorageIJMER
In this paper, a new isolated wind- hydro hybrid generation system comprising one squirrel -cage induction generator (SCIG) driven by a variable-speed wind turbine and another synchronous generator driven by constant power hydro turbine feeding three phase four wire local loads is proposed. The system utilizes two back to back connected voltage-source converters (VSCs) with a battery energy storage system at their dc link. The main objective of the control algorithm for the VSC is to achieve control of the magnitude and the frequency of the load voltage. The proposed wind-hydro hybrid system has a capability of bidirectional active- and reactive-power flow, by which it controls the magnitude and the frequency of the load voltage. The proposed electromechanical system is modelled and simulated in MATLAB using Simulink.
Optimal Placement of Distributed Generation on Radial Distribution System for...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.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Distributed energy units cannot be directly integrated into the power grid due to their inherently varying output. An interfacing technology is required. The power electronic interface is used for connecting distributed energy resources to the smart grid. It can also be used in any type of electric vehicles. It does not store energy in its circuitry. It receives power from the distributed energy source and converts it to power at the required voltage and frequency. This paper provides a brief introduction on power electronic interface. Matthew N. O. Sadiku | Adedamola A. Omotoso | Sarhan M. Musa "Power Electronic Interface" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-1 , December 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29394.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/29394/power-electronic-interface/matthew-n-o-sadiku
This paper discusses about a LabVIEW based controller for the hybrid renewable energy system operated AC-DC microgrid with the major objectives of: i) predicting the power generation potential of the solar–PV and wind generators ii) effective power management iii) load scheduling based on the available power with the renewable sources and iv) grid/islanding mode of operation of the microgrid. In order topredict the output power of wind generator and Solar-PV system, an artificial neural network is developed.The laboratory-scale model of three phase, 400 V, 10 kVA microgrid structure is developed at National Institute of Technology Calicut, India. The developed LabVIEW based controller has been tested successfully for a real-time load and source in the laboratory environment. Test results show that the designed controller is effectively managing the output powerof the primary energy sources under different scenarios.
Performance Improvement Of Bengali Text Compression Using Transliteration And...IJERA Editor
In this paper, we propose a new compression technique based on transliteration of Bengali text to English. Compared to Bengali, English is a less symbolic language. Thus transliteration of Bengali text to English reduces the number of characters to be coded. Huffman coding is well known for producing optimal compression. When Huffman principal is applied on transliterated text significant performance improvement is achieved in terms of decoding speed and space requirement compared to Unicode compression
Restoration plans are guidelines for system operators to use during blackout and blackstart events. However, many utilities face several challenges to their restoration plans including generation retirements affecting the availability of next-start generators and steep increasing levels of renewable generation. This paper addresses the two challenges highlighted by dynamically assessing one of Dominion Energy’s blackstart cranking paths and studying the impact of photovoltaic (PV) generation during restoration events. Potentially useful PV inverter control schemes are identified and studied to aid the restoration process. One of the blackstart cranking paths that is currently in Dominion Energy’s system restoration plan is studied using PSSE. A 20 MW capacity PV farm located on the path is used to study the impact of PV considering no control scheme, a voltage control scheme, and two active power control techniques: curtailment-based or battery storage. The voltage control scheme is found to successfully mitigate over-voltage from energizing long and extra-high voltage lines. Both active power control techniques improve the frequency nadir although, operational and implementation challenges have been identified for these schemes.
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.
07 22 sep15 8711 18507-2-sm -edit_FACT Device for Reactive Power Compensation...IJPEDS-IAES
In the deregulating electricity market, many private sector power producers
are participating actively. With growing number of the wind mills and solar
power generation, the reactive power production will be more because of
induction generator and inductive type load. Many blackouts have happened
in the past decades due to more reactive power which lead to a decrease in
the magnitude of real power. It is very essential to compensate the reactive
power, increase the real power flow in the transmission line, increase the
transmission efficiency, improve the system stability and be in a safer place
to save the fossil fuels for the future. In this paper the importance of reactive
power and its various compensation techniques are applied to a five bus
deregulated test case modeled and analyzed. The simulations were done
using Matlab Simulink, for various FACT controllers such as STATCOM,
SVC, SSSC and UPFC compensation and the results were tabulated and
compared.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
A Review on Design and Development of high Reliable Hybrid Energy Systems wit...IJPEDS-IAES
Hybrid Energy system is a combination of two or more different types of energy resources. Now a day this hybrid energy system plays key role in various remote area power applications. Hybrid energy system is more reliable than single energy system. This paper deals with high reliable hybrid energy system with solar, wind and micro hydro resources. The proposed hybrid system cable of multi mode operation and high reliable due to non communicated based controllers (Droop Characteristic Control) are used for optimal power sharing. Size of battery can be reduced because hydro used as back up source and Maximum power point Tracking also applied to solar and wind energy systems.
Modeling, Control and Power Management Strategy of a Grid connected Hybrid En...IJECEIAES
This paper presents the detailed modeling of various components of a grid connected hybrid energy system (HES) consisting of a photovoltaic (PV) system, a solid oxide fuel cell (SOFC), an electrolyzer and a hydrogen storage tank with a power flow controller. Also, a valve controlled by the proposed controller decides how much amount of fuel is consumed by fuel cell according to the load demand. In this paper fuel cell is used instead of battery bank because fuel cell is free from pollution. The control and power management strategies are also developed. When the PV power is sufficient then it can fulfill the load demand as well as feeds the extra power to the electrolyzer. By using the electrolyzer, the hydrogen is generated from the water and stored in storage tank and this hydrogen act as a fuel to SOFC. If the availability of the power from the PV system cannot fulfill the load demand, then the fuel cell fulfills the required load demand. The SOFC takes required amount of hydrogen as fuel, which is controlled by the PID controller through a valve. Effectiveness of this technology is verified by the help of computer simulations in MATLAB/SIMULINK environment under various loading conditions and promising results are obtained.
A CONTROL APPROACH FOR GRID INTERFACING INVERTER IN 3 PHASE 4 WIRE DISTRIBUT...IJMER
With the increase in load demand, the Renewable Energy Sources (RES) are
increasingly connected in the distribution systems which utilizes power electronic
Converters/Inverters. Nowadays, 3-phase 4-wire distribution power system has been widely used in
residential and office buildings, manufacturing facilities, schools etc This paper presents a novel
control strategy for achieving maximum benefits from the grid-interfacing inverters when installed in
3-phase 4-wire distribution systems. The inverter can thus be utilized as: 1) power converter to inject
power to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics and
load neutral current. All of these functions may be accomplished either individually or
simultaneously. This new control concept is demonstrated with extensive MATLAB/Simulink
simulation studies
A Novel Technique for Enhancing Active and Reactive Power Quality for Renewab...IJMER
Renewable energy resources (RES) are being increasingly connected in distribution systems utilizing power electronic converters. This paper presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to inject power generated from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies and results.
A Flexible AC Distribution System for a Microgrid with a Photovoltaic System ...IJMTST Journal
This paper presents a FACT ac distribution system device for micro grid applications. The device aims to improve the power quality and reliability of the overall power distribution system that the micro grid is connected to. The control design employs a new model predictive control algorithm which allows faster computational time for large power systems by optimizing the steady-state and the transient control problems separately. Extended Kalman filters are also employed for frequency tracking and to extract the harmonic spectra of the grid voltage and the load currents in the micro grid. Simulation results is verified through different case studies.
Mitigation of Voltage Fluctuations in Power System Using STATCOMIJERA Editor
Wind energy being a renewable source of energy is enjoying a rapid growth globally. However, wind energy being an uncontrollable source of energy coupled with the fact that it uses distributed induction generators for power conversion poses a challenge in integrating a large scale wind-farm into a weak power system. An actual weak power system with two large Wind-Farms (WFs) coupled to it is introduced as part of this study. A model of this integrated system along with a STATCOM for steady state and dynamic impact study is developed in the MATLAB/Simulink environment. The power quality issues are highlighted and a centralized STATCOM is proposed to solve the issue of the voltage fluctuations in particular in addition to addressing the other issues. Based on the results obtained from the simulation, the system voltage control issues are analyzed and the location of STATCOM is assessed. Finally, a STATCOM control strategy for suppression of voltage fluctuations is presented.
Human population of the world and its Electrical
power demand is increasing day by day. The available fossil
fuel energy resources are being depleted day by day. So it is a
wise decision to absorb the natural renewable energy
resources. Among the other natural resources, solar energy is
also a precious available energy source. In Pakistan abundance
solar energy can be easily extracted.
In this research work, impacts of solar generation system are
analyzed while integrated with 11kV radial distribution feeder.
PV system is integrated with feeder in three different ways by
using SINCAL software and its impacts in terms of the power
loss, voltage profile and short circuit level are analyzed. When
PV system is integrated with HT side it results negligible
increment in voltage, no change in LT losses, negligible
decrement in HT losses and no change in short circuit level.
When PV system is connected with LT bus-bar of each
transformer, there is significant increment in voltage, small
decrement in LT losses, significant decrement in HT losses and
smaller increment in short circuit level. When PV system is
connected with each load, there is significant increment in
voltage, large decrement in LT losses, significant decrement in
HT losses and smaller increment in short circuit level.
Isolated Wind Hydro Hybrid Generation System with Battery StorageIJMER
In this paper, a new isolated wind- hydro hybrid generation system comprising one squirrel -cage induction generator (SCIG) driven by a variable-speed wind turbine and another synchronous generator driven by constant power hydro turbine feeding three phase four wire local loads is proposed. The system utilizes two back to back connected voltage-source converters (VSCs) with a battery energy storage system at their dc link. The main objective of the control algorithm for the VSC is to achieve control of the magnitude and the frequency of the load voltage. The proposed wind-hydro hybrid system has a capability of bidirectional active- and reactive-power flow, by which it controls the magnitude and the frequency of the load voltage. The proposed electromechanical system is modelled and simulated in MATLAB using Simulink.
Optimal Placement of Distributed Generation on Radial Distribution System for...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.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Distributed energy units cannot be directly integrated into the power grid due to their inherently varying output. An interfacing technology is required. The power electronic interface is used for connecting distributed energy resources to the smart grid. It can also be used in any type of electric vehicles. It does not store energy in its circuitry. It receives power from the distributed energy source and converts it to power at the required voltage and frequency. This paper provides a brief introduction on power electronic interface. Matthew N. O. Sadiku | Adedamola A. Omotoso | Sarhan M. Musa "Power Electronic Interface" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-1 , December 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29394.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/29394/power-electronic-interface/matthew-n-o-sadiku
This paper discusses about a LabVIEW based controller for the hybrid renewable energy system operated AC-DC microgrid with the major objectives of: i) predicting the power generation potential of the solar–PV and wind generators ii) effective power management iii) load scheduling based on the available power with the renewable sources and iv) grid/islanding mode of operation of the microgrid. In order topredict the output power of wind generator and Solar-PV system, an artificial neural network is developed.The laboratory-scale model of three phase, 400 V, 10 kVA microgrid structure is developed at National Institute of Technology Calicut, India. The developed LabVIEW based controller has been tested successfully for a real-time load and source in the laboratory environment. Test results show that the designed controller is effectively managing the output powerof the primary energy sources under different scenarios.
Performance Improvement Of Bengali Text Compression Using Transliteration And...IJERA Editor
In this paper, we propose a new compression technique based on transliteration of Bengali text to English. Compared to Bengali, English is a less symbolic language. Thus transliteration of Bengali text to English reduces the number of characters to be coded. Huffman coding is well known for producing optimal compression. When Huffman principal is applied on transliterated text significant performance improvement is achieved in terms of decoding speed and space requirement compared to Unicode compression
Research On Preserving User Confidentiality In Cloud Computing – Design Of A ...IJERA Editor
Cloud Computing creates a dynamic resource sharing platform. Using cloud technologies such as virtualization, data can be provided to the active users who are at high need to utilize the resources provided within the cloud. As this data (or service) is stored (or offered) outside the data owner's boundaries, they are skeptical for utilizing cloud technology in order to store or utilize their data or service. There are many issues for these active clients (companies or individuals) to be petrified at the thought of using cloud computing paradigm. Some of the main issues that make the clients not to choose cloud computing may be determined because of three important security aspects such as confidentiality, integrity, and availability. This research focused on the security models that relate confidentiality issues. A literature Review is performed for analyzing the existing confidentiality frameworks and security models in the area of grid computing, cluster computing and virtualization. A new theoretical framework is then designed to overcome confidentiality issues thereby improving the client‟sgeneric understanding of cloud computing services. The resulting framework when implemented in real world would motivate clients to transform their businesses on to cloud.
Applications and Properties of Unique Coloring of GraphsIJERA Editor
This paper studies the concepts of origin of uniquely colorable graphs, general results about unique vertex colorings, assorted results about uniquely colorable graphs, complexity results for unique coloring Mathematics Subject Classification 2000: 05CXX, 05C15, 05C20, 37E25.
Compression is playing a vital role in data transfer. Hence, Digital camera uses JPEG standard to compress the captured image. Hence, it reduces data storage requirements. Here, we proposed FPGA based JPEG encoder. The processing system is coupled with DCT and then it is quantized and then it is prepared for entropy coding to form a JPEG encoder
Life Cycle Energy Analysis of a Traditional Building in India (A Case Study)IJERA Editor
Some of the major environmental concerns of our time are the depletion of the ozone layer, the wastage of limited resources such as oil, gas and minerals, the loss of forested areas, toxic chemical manufacture and emissions, the obliteration of natural practice with the effluence of land, water and air. The environmental crisis has made us focus our attention on the impact buildings will have on the environment. Hence we need to be aware of the possibilities of saving energy by designing buildings according to vernacular architecture, which normally involves informal building compositions during the method of traditional building with local associates in addition to locally available materials. This paper discusses the consequence of material assortment and construction scheme with respect to its energy incurred throughout its existing sequence (Unrefined fabric acquisition, product manufacture & transportation, construction, operation and maintenance, renovation and demolition). It is all mainly related to the multi-faceted nature of environmental sustainable design.
Subsurface Determination Of Cavities In Limestone Rock Area By Geoelectric Me...IJERA Editor
Two Dimensional of geoelectric method can be used to find out the conductive formation in the earth surface. The purpose of this research is to give the description about the geological subsurface formation, that the high resistivity value is indicate the potential area of cave and void in the limestone rocks. The dipole dipolegeoelectric method is used in this research with the path of lines is 250 m with 10 m electrode spacing. The total lines is 7 and the azimuth is from east to west. Resistivity method is started with inject the electrical current into the earth by current electrode, then potential difference will arise and measured by potential electrode. Variation value of resistance for each layer rock can calculated by divided potential defference with current value. The existence of the cavity is known by the resistivity value is more than 2500 ohm-m, while the cracks have a resistivity of 1500 to 2500 ohm-m.
Efficient Planning Scheduling and Delay Analysis of Residential ProjectIJERA Editor
Planning and scheduling have become an essential part of any project for the timely and economical completion of the project. A proper construction schedule can be used for different purposes. By using construction schedule to predict project completion, contractors can adjust crew size, shifts or equipment to speed or slow the progress. All the construction projects will vary from each other in size. All the projects have time constraint. Delay in completion of project will increase the overall cost of the project. Small projects can be managed efficiently manually; whereas large projects are not so large projects can be better handled by the use of computers. Many types of software are available with the help of which project management can be done easily. Large quantities of different kinds of resources are also required for execution and the risk is more in the case of projects. So planning and scheduling of activities for construction of big projects is essential. In this study, an effort is made in planning, scheduling and delay analysis updating of various activities, which is done by using MS Project and MS Excel software, manpower of each activity is determined and allocation is done using the software. Labor requirement for each activity is calculated from standards obtained from site. An updated schedule, which helps to finish the project well in time with optimum resources and update helps in delay analysis, is under the scope of this study.
The Use Of Permeable Concrete For Ground Water RechargeIJERA Editor
In order to develop Smart Cities in India, we need to develop smart technologies and smart construction materials. Permeable concrete an innovative material is environment friendly and a smart material which can be used for construction of several structures. In India, the ground water table is decreasing at a faster rate due to reduction in ground water recharge. These days, the vegetation cover is replaced by infrastructure hence the water gets very less opportunity to infiltrate itself into the soil. If the permeable concrete which has a high porosity is used for the construction of pavements, walking tracks, parking lots, well lining, etc. then it can reduce the runoff from the site and help in the ground water recharge. Such type of smart materials will play an important role for Indian conditions where government is putting lot of efforts to implement ground water recharging techniques. During the research work, the runoff for a particular storm was calculated for a bitumen pavement on a sloping ground. Later after studying the various topographical features, the traffic intensity and the rainfall for that particular area, the concrete was designed and tested for the different proportion and thus the mix design for the permeable concrete was finalized based upon its permeability and strength characteristics. Later by using this permeable concrete the infiltration and runoff for the same storm was compared and studied. The research paper will thus give an account of the properties of permeable concrete where it can be used over an existing road.
Chosen Problems in Agro Logistics - a Proposals to the Use of Selected Indica...IJERA Editor
The article presents examples of tools which can effectively contribute to, among others, better selection of machines and coordination of their performance and the mass transport stream. The following formulae can be useful in practice: the number of necessary machine units, mass flow, intake capacity of storage facilities, duration of the transport cycle, load capacity utilization rate and performance measure of means of transport (or a set of means of transport). Their use, according to the authors, will allow agricultural producers to minimise various kinds of risks which for many reasons are extremely high in this industry.
Total Ozone Content over Kathmandu from TOMS ObservationsIJERA Editor
This paper reports the trend of total ozone content (TOC) over Kathmandu for 10 years period from 1979-1988 derived from Total Ozone Mapping Spectrometer (TOMS) satellite observations. The trends of daily, monthly, seasonal and annual variations of TOC over Kathmandu have been analyzed. The result exemplifies that during the whole study period, the TOC is found to be maximum on February 11, 1979 with a value of 352 DU and the lowest ozone concentration is on January 18, 1980 with a value of 243 DU. Similarly, the minimum value of monthly average TOC is 260 DU in November, while the maximum values is 293 DU on May. The amplitude of variations of monthly average TOC is 12.7% in terms of the percentage from the mean value. The results also show that TOC is highly seasonal dependent with larger TOC in summer season compared to the equinox and winter seasons. The summer TOC on average is 7.5% higher than in winter season and only by 1.8% higher than in equinox. The TOC in equinox is higher than winter by 5.7% on average. The average annual value of TOC exhibits slightly variable with a maximum in 1979 (281 DU) and minimum in 1984 (274 DU), which differs only by 2.5%. The average value of TOC during the whole study period is 277 DU, which indicates good amount of stratospheric ozone content over Kathmandu.
Dielectric properties of Ni-Al nano ferrites synthesized by citrate gel methodIJERA Editor
Ni–Al ferrite with composition of NiAlxFe2-xO4 (x=0.2, 0.4 0.6, and 0.8, ) were prepared by citrate gel method. The Dielectric Properties for all the samples were investigated at room temperature as a function of frequency. The Dielectric constant shows dispersion in the lower frequency region and remains almost constant at higher frequencies. The frequency dependence of dielectric loss tangent (tanδ) is found to be abnormal, giving a peak at certain frequency for mixed Ni-Al ferrites. A qualitative explanation is given for the composition and frequency dependence of the dielectric loss tangent.
Optimization of Process Parameters And Dielectric Fluids on Machining En 31 B...IJERA Editor
The electric discharge machining is the one of the most desirable machining process for the materials which are having high hardness and good thermal conductivity. The EDM process surpassed through the technological barriers by overcoming limitations like processing speed, material conductivity, dimensional accuracy, and surface finish and so on. However, environmental impact due to release of toxic emissions aerosols during the process, poor operational safety due to fire hazard, electromagnetic radiation and non-bio degradable waste are the major problems concerned with conventional dielectric fluids (i.e. kerosene, hydro carbon, etc.,). To reduce the problems with conventional die electric fluids waste palm oil blended with kerosene is used. The process is mostly used in situations where intricate, complex shapes need to be machined in very hard materials. The objective of this work is to study the influence of four design factors current (I), voltage (V), pulse on(P on), and pulse off(P off) which are the most relevant parameters to be controlled by the EDM process over machining characteristics such as material removal rate (MRR) characteristics of surface integrity such as average surface roughness (Ra). Multi Objective optimization of process parameters is done by using TOPSIS
Monitoring Of Water Logged Areas in Krishana Canal Command Using Gis TechniquesIJERA Editor
Degradation of land due to waterlogging in sugarcane track of western Maharashtra is a serious problem. Here researchers had understood the problem of the waterlogged areas by preparing an inventory using GIS and GPS techniques. Krishna Canal Command area is lies in Satara and Sangli districts. Total length of canal is 86 km, out of which 21 km length is comes under study area. The command area is divided in 4 segments, out of which, the present study deals with Segment IV. Water table map was prepared using water depth data at 231 well locations. The entire analysis was carried out in ArcGIS software. GIS – Spatial Analysis tool, point data was rasterised, and surfaces for water table were generated. Risk zonation maps were prepared using the critical limits given by IRD, Pune. Water table surface was intersected with village boundary layers. Risk zonation map of water table suggests that the two villages namely Nagral and Burli situated close to canal are most vulnerable due to high water table. Almost 36 % of the total study area of land covering partially the villages Nagral, Burli, Shirasgaon, Amnapur, Palus, and Yelavi were found under critical water table condition. In segment IV total area of 792 ha in villages Nagral, Burli, Amnapur, Yelavi, and Bhilawadi fall under the P1 category affected most badly by the waterlogging condition. Prioritization of villages based on AWI suggests that out of the total eight villages, five villages namely Amnapur, Burli, Bhilawadi, Nagral and Yelavi are falling under P1 priority category, need immediate attention for remedial measures
An Effective Security Mechanism for M-Commerce Applications Exploiting Ontolo...IJERA Editor
Health organizations are beginning to move mobile commerce services in recent years to enhance services and quality without spending much investment for IT infrastructure. Medical records are very sensitive and private to any individuals. Hence effective security mechanism is required. The challenges of our research work are to maintain privacy for the users and provide smart and secure environment for accessing the application. It is achieved with the help of personalization. Internet has provided the way for personalization. Personalization is a term which refers to the delivery of information that is relevant to individual or group of individuals in the format, layout specified and in time interval. In this paper we propose an Ontology Based Access Control (OBAC) Model that can address the permitted access control among the service providers and users. Personal Health Records sharing is highly expected by the users for the acceptance in mobile commerce applications in health care systems.
Cyclic Response of Reinforced Concrete Moment Resisting Beams Repaired with E...IJERA Editor
This paper presents the results of a quasi-static cyclic test carried out on a reinforced concrete special moment resisting beam to study the efficiency of traditional repair techniques in restoring the strength and stiffness capacity of damaged RC beams. The beam was tested in a cantilever mode and was subjected to a standard loading protocol with increasing amplitude of displacement cycles. The final damage state of the beam consisted of severe cracking and spalling of the cover concrete. The cracks were repaired with low-viscosity injection epoxy and the spalled concrete was repaired with early-strength grout. The repaired specimen was subjected to the same loading protocol as the original specimen to study the efficiency of the repair technique employed. It was observed that epoxy injection is not effective in restoring the strength and stiffness of beams with bar slip of longitudinal bars at the support end.
Effect of Weaknesses of the Internal Control Systems And NonCompliance With S...IJERA Editor
The purpose of this study was to see whether there is an influence of Weaknesses of the Internal Control System and Non-compliance With Statutory Provisions on the audit opinion of the audit board. The weakness of the internal control system measured by the audit findings Audit Board consisting of weaknesses of the accounting control system and reporting, and weaknesses of the budget implementation control system and weaknesses of the internal control structure. While non-compliance with statutory provisions are measured based on the audit findings Audit Board consisting of local loss, the potential loss of local , lack of receipt, administration, waste, inefficiency and ineffectiveness. This study is a survey of the region of the provincial government of DKI Jakarta and Banten for 2010 to 2014. Samples in this study were all the Local Government Unit that generate financial reports of local governments totaling nine units, so this study is census research, in the sense that the entire population sampled. Data analysis method used is the ordinal logistic regression because the dependent variable is the rank (category) and the data is not normal. From the results of the data analysis and discussion, it can be concluded that the weaknesses of the internal control system and non-compliance with statutory provisions affect the audit opinion of the audit board either jointly or partially.
Selection of Supplier by Using Saw and Vikor MethodsIJERA Editor
Now a days, Lean manufacturing becomes a key strategy for global competition. In this environment the most important process is the efficient selection of suppliers. In any organization various criteria such as quality, cost, location etc are used for the selection of supplier which plays a vital role in the industry. In the present work multi criteria decision making (MCDM) methods are used such as SAW method and VIKOR method. It is used to select the best supplier for implementing the spring manufacturing industry. Choice of the efficient supplier could be a complicated and is a complex problem and this draw back associate degreed a key success for an organization. In this paper linguistic fuzzy data is used to search out the ratings and weights and also the introduced methodologies employed to pick the efficient supplier
The State of Analytical Instruments in Some Environmental Pollution Control L...IJERA Editor
The state of the environmental laboratories involved in monitoring environmental pollution control in Nigeria has been studied in this research. The research was undertaken by visiting four analytical laboratories involved in environmental pollution control in Nigeria. The analytical laboratories visited are those of Nigerian National Petroleum Corporation (NNPC) Kaduna, Ashaka cement factory, regional laboratory of the Federal Ministry of Water Resources Gombe, and the National Reference laboratory Lagos. In these laboratories results were collected in the laboratories, interviews were carried out and analytical instruments available were documented. It was discovered that, in these laboratories many standard analytical instruments needed for quality environmental pollution control and monitoring are lacking. Comparison of analytical instruments found in these laboratories with those found in literature revealed that many needed analytical instruments are missing. It is the position of this work that the gap between the environmental analytical instruments found in literature and that found in the research laboratories is very large and calls for concern
Modeling and Steady State Response Analysis of Interconnected Hybrid Renewable Energy Network with Embedded VSC - MTDC Transmission System for Secure and Efficient Power Delivery
A NOVEL CONTROL STRATEGY FOR POWER QUALITY IMPROVEMENT USING ANN TECHNIQUE FO...IJERD Editor
The proposed system presents power-control strategies of a Micro grid-connected hybrid generation
system with versatile power transfer. This hybrid system allows maximum utilization of freely available
renewable energy sources like wind and photovoltaic energies. For this, an adaptive MPPT algorithm along with
standard perturbs and observes method will be used for the system.
The inverter converts the DC output from non-conventional energy into useful AC power for the
connected load. This hybrid system operates under normal conditions which include normal room temperature
in the case of solar energy and normal wind speed at plain area in the case of wind energy. However, designing
an optimal micro grid is not an easy task, due to the fact that primary energy carriers are changeable and
uncontrollable, as is the demand. Traditional design and optimization tools, developed for controlled power
sources, cannot be employed here. Simulation methods seem to be the best solution.
The dynamic model of the proposed system is first elaborated in the stationary reference frame and
then transformed into the synchronous orthogonal reference frame. The transformed variables are used in
control of the voltage source converter as the heart of the interfacing system between DG resources and utility
grid. By setting an appropriate compensation current references from the sensed load currents in control circuit
loop of DG, the active, reactive, and harmonic load current components will be compensated with fast dynamic
response, thereby achieving sinusoidal grid currents in phase with load voltages, while required power of the
load is more than the maximum injected power of the DG to the grid. In addition, the proposed control method
of this paper does not need a phase-locked loop in control circuit and has fast dynamic response in providing
active and reactive power components of the grid-connected loads.
Performance Analysis of DC Micro Grid with PV-Fuel Cell Hybrid GenerationIJMREMJournal
Conventional energy resources are being replaced by Renewable energy sources mainly due to increasing
environmental concerns. Photovoltaic (PV) and Fuel cell (FC) are suitable to be used in modern DC microgrids
due to their DC output. In this research work, a DC microgrid structure is proposed for small residential areas
using hybrid PV and FC generation. Power Electronic converters are used to regulate generated voltage of the
two sources for integration to a common DC bus. Proposed system is simulated using MATLAB SIMULINK to
observe its performance. Simulation results show that output voltage is properly maintained at different DC
DESIGN AND SIMULATION ANALYSIS OF SEVEN LEVEL CASCADED GRID CONNECTED INVERTE...ijiert bestjournal
This paper presents the simulation analysis of sev en level cascaded grid connected inverter and also compared with five level inverter for %THD for voltage and current by using level shifted PWM techniques. The proposed system are modeled and simulated through computer software tool using MATLAB /SIMULINK. This paper also presen ts the design and development of the seven level cascaded grid connected inverter.The LC filter is also use in the output side to further reduce the THD values.Seven level inverter is utili se as a power converter to inject power generated from pv source to the grid.Multilevel inv erters have been mainly used in medium- or high-power system applications,such as static reac tive power compensation and adjustable-speed drives. In these applications,due to the limitatio ns of the currently available power semiconductor technology.The term multilevel began with the three-level converter. Subsequently,several multilevel converter topologi es have been developed. However,the elementary concept of a multilevel converter to ach ieve higher power is to use a series of power semiconductor switches with several lowerVoltage dc sources to perform the power conversion by synthesizing a staircase voltage waveform. Capac itors,batteries,and renewable energy voltage sources can be used as the multiple dc volt age sources. The commutation of the power switches aggregate these multiple dc sources in ord er to achieve high voltage at the output;however,the rated voltage of the power semiconduct or switches depends only upon the rating of the dc voltage sources to which they are connected Percentage of THD for R,RL,RLC load taken and simulation results analyse and studied an d comparison made between five level and seven level .
Electric Vehicle as an Energy Storage for Grid Connected Solar Power SystemIAES-IJPEDS
In the past few years the growing demand for electricity and serious concern
for the environment have given rise to the growth of sustainable sources like
wind, solar, tidal, biomass etc. The technological advancement in power
electronics has led to the extensive usage of solar power. Solar power output
varies with the weather conditions and under shading conditions. With the
increasing concerns of the impacts of the high penetration of Photovoltaic
(PV) systems, a technical study about their effects on the power quality of
the utility grid is required. This paper investigates the functioning of a gridtied
PV system along with maximum power point tracking (MPPT)
algorithm. The effects of varying atmospheric conditions like solar irradiance
and temperature are also taken into account. It is proposed in this work that
an Electric Vehicle (EV) can be used as an energy storage to stabilize the
power supplied to the grid from the photovoltaic resources. A coordinated
control is necessary for the EV to obtain desired outcome. The modeling of
the PV and EV system is carried out in PSCAD and the proposed idea is
verified through simulation results utilizing real field data for solar irradiance
and temperature.
PV Hybrid System with DSTATCOM for Residential ApplicationsIDES Editor
Now a days PV based energy systems are playing a
vital role among all the renewable energy sourcesin our day
to day life.Proper control should be required to meet the exact
load conditions such that it should satisfy the non-linear
nature of both the solar irradiance and load. In this paper, a
battery is also incorporated along with the PV system to meet
the necessary drop due to change in weather conditions. Here,
a proper control is achieved by using DSTATCOM to
compensate the reactive power. This paper proposes an
advanced technique of PWM to generate the gating pulses
and applied to a Cascaded H-Bridge multilevel inverter to
improve the voltage quality. Here, the entire system is designed
to meet the load of Mogulthur (W.G.Dt. Andhra Pradesh).
Simulation results are presented through Matlab/Simulink
by taking different cases into consideration.
Design and Simulation of a Three Phase Power Converter Connected To a Distrib...IJERA Editor
The distributed generation systems based on renewable energy sources (photovoltaic, fuel cells, and storage systems such as ultra capacitors and batteries) are of great interest due to their low environmental impact and technical advantages such as improvements in voltage levels and reduced power losses when a distributed generation system is installed in radial lines. Two control algorithms were proposed to improve the grid-connected and intentional-islanding operations methods, in which the distributed generation system must detect the situation and switch from power or current to voltage as a control variable to provide constant rms voltage to the local loads. The power flow between the grid and the distributed generation is controlled by applying a power/voltage method that regulates the amplitude and the displacement of the grid voltage synthesized by the distributed generation, while a phase-locked loop algorithm is used to synchronize the grid and distributed generation.
A Three Phase Multi Level Converter for grid Connected PV SystemIAES-IJPEDS
Photovoltaic energy is a wide kind of green energy. A high performance on these systems is needed to make the most of energy produced by solar cells. Also, there must be a constant adaptation due to the continuous variation of power production. Control techniques for Power Converters like the MPPT algorithm (Maximum Power Point Tracking) present very good results on photovoltaic chains. Nevertheless, losses on power elements reduce global performance and the voltage/current adaptation is not always possible. This paper presents a single-phase 11-level (5 H-bridges) cascade multilevel DC- AC grid-tied inverter. Each inverter bridge is connected to a 200 W solar panel. OPAL-RT lab was used as the hardware in the loop (HIL) real-time control system platform where a Maximum Power Point Tracking (MPPT) algorithm was implemented based on the inverter output power to assure optimal operation of the inverter when connected to the power grid as well as a Phase Locked Loop (PLL) for phase and frequency match. A novel SPWM scheme is proposed in this paper to be used with the solar panels that can account for voltage profile fluctuations among the panels during the day. Simulation and experimental results are shown for voltage and current during synchronization mode and power transferring mode to validate the methodology for grid connection of renewable resources.
This paper presents application and control of the gate-controlled series capacitor (GCSC) for series compensation and subsynchronous resonance (SSR) damping in doubly-fed induction generator (DFIG)-based wind farms. The GCSC is a new series FACTS device composed of a fixed capacitor in parallel with a pair of antiparallel gate-commuted switches. The study considers a DFIG-based wind farm, which is connected to a series-compensated transmission line whose parameters are derived from the IEEE first benchmark model for computer simulation of the SSR. The small-signal stability analysis of the system is presented, and the eigenvalues of the system are obtained. Using both modal analysis and time-domain simulation, it is shown that the system is potentially unstable due to the SSR mode. Therefore, the wind farm is equipped with a GCSC to solve the instability of the wind farm resulting from the SSR mode, and an SSR damping controller (SSRDC) is designed for this device using residue-based analysis and root locus diagrams. Using residue-based analysis, the optimal input control signal to the SSRDC is identified, which can damp the SSR mode without destabilizing other modes, and using root-locus analysis, the required gain for the SSRDC is determined. MATLAB/Simulink is used as a tool for modeling, design, and time-domain simulations.
Implementation of a grid-tied emergency back-up power supply for medium and l...IJECEIAES
Emergency back-up power supply units are necessary in case of grid power shortage, considerably poor regulation and costly establishment of a power system facility. In this regard, power electronic converters based systems emerge as consistent, properly controlled and inexpensive electrical energy providers. This paper presents an implemented design of a grid-tied emergency back-up power supply for medium and low power applications. There are a rectifier-link boost derived DC-DC battery charging circuit and a 4-switch push-pull power inverter (DC-AC) circuit, which are controlled by pulse width modulation (PWM) signals. A changeover relay based transfer switch controls the power flow towards the utility loads. During off-grid situations, loads are fed power by the proposed system and during on-grid situations, battery is charged by an AC-link rectifier-fed boost converter. Charging phenomenon of the battery is controlled by a relay switched protection circuit. Laboratory experiments are carried out extensively for different loads. Power quality assessments along with back-up durations are recorded and analyzed. In addition, a cost allocation affirms the economic feasibility of the proposed framework in case of reasonable consumer applications. The test-bed results corroborate the reliability of the research work.
Maximum power point tracking and space vector modulation control of quasi-z-s...IJECEIAES
The quasi-Z-source inverter (qZSI) become one of the most promising power electronic converters for photovoltaic (PV) applications, due to its capability to perform a buck-boost conversion of the input voltage in a single stage. The control strategy based maximum power point tracking (MPPT) and proportional integral (PI) controller are well known in grid-connected with traditional configuration but not in qZSI. This paper presents a control strategy for qZSI grid-connected based on the MPPT algorithm and the linear control by PI controllers. This is complemented by the capability to efficiently transfer the harvested power to the grid, ensuring a unity power factor. The proposed control strategy effectively separates the control mechanisms for the direct current (DC) and alternating current (AC) sides by utilizing the two control variables, the shoot-through duty ratio and the modulation index. An adapted space vector modulation technique is then utilized to generate the switching pulse width modulation (PWM) signals, using these two control variables as inputs. The proposed approach was tested and validated under MATLAB/Simulink and PLECS software.
Similar to Grid Integration of Large PV Power Systems Using HVDC Link (20)
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
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Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Grid Integration of Large PV Power Systems Using HVDC Link
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Grid Integration of Large PV Power Systems Using HVDC Link
Gamal Sowilam*
, Tamer Kawady**
and Raed Shalwala***
*Umm Al-Qura University, Faculty of Eng. & Islamic Architecture Saudi Arabia / Helwan university, Faculty of
Engineering, Egypt.
**Umm Al-Qura University, Faculty of Eng. & Islamic Architecture Saudi Arabia / Minoufiya University,
Faculty of Engineering, Egypt.
*** Umm Al-Qura University, Faculty of Eng. & Islamic Architecture Saudi Arabia.
ABSTRACT
This paper explores the interconnection of large scale Photo-Voltaic (PV) systems to the grid though a High
Voltage Direct Current (HVDC) link. HVDC link is recently utilized for transmission lines longer than 50 km. It
is usually utilized to interconnect two asynchronous grids with the same or different frequencies while avoiding
stability disturbances greatly. A suitable Maximum Power Point Tracking (MPPT) techniques is employed to
control the performance of the integrated PV system. The system of the HVDC link has two 12-pulse converter
using thyristor-bridges. The delay and the extinction angles at the rectifier and the inverter units control the flow
and the quantity of the transmitted power from the PV system into the grid. Fixed capacitors and filters are used
to provide the AC side with the required reactive power and reduce the harmonic contents. For evaluation
purposes, different simulation investigations are carried out with a detailed modeling using the MATLAB.
These tests corroborate the efficacy of HVDC link for integrating large PV systems to electrical grids.
Keywords: PV power plant, HVDC link, Grid Integration, Bipolar link, 12-pulse rectifier, 12-pulse inverter,
PWM inverter, DC boost choppers
I. INTRODUCTION
Due to the increasing exhausting of fossil
fuels and the exaggerated demands of energy
resources in the world, renewable energy resources
have nowadays an increasing importance. This
encourages the research efforts in different countries
all over the world to declare their own targets of
penetrating levels of renewable energy systems in
the future. As example, the European Union has set
its target of renewable energy generation to be over
32% of its total generated power by 2030 [1].
Among the most common renewable energy
resources, solar energy arises as the most practical
and suitable one for almost all countries. Solar PV
systems are the matured and financially viable
option for power generation [2]. Large integrated PV
power plants are mostly utilized nowadays to be
connected to the transmission (or sub-transmission)
level. As reviewed in the literatures, PV power
plants experience a sharper growth of their
penetration levels as compared with wind power
resources from 2010 to present [3]. For Saudi Arabia
in particular, a 16 GW of grid-integrated PV power
plants is a national target up to 2032.
On the other hand, different kinds of
problems arise with integrating PV systems to the
grid as compared with the experienced ones with
conventional power plants. The fluctuation of PV
output power due to the variation of solar irradiance
is one of the major problems for grid integration [4,
5]. This impacts the electrical grid remarkably.
Among these serious impacts, the PV plants may
adversely influence the dispatch strategies, the
spinning reserve routines, voltage stability and
angular stability [6-9]. Hence, eliminating such
problems is essential in modern power grids.
Gang Liu el. al. present a feasibility study
of PV, wind, biomass and battery storage based
Hybrid Renewable Energy (HRE) systems providing
the electricity to a residential area in Australia [10].
Characterization of the waveform distortion during
the operation of grid-connected PV inverters was
investigated with recorded and experimental
measurements by Schlabbach et. al. as shown in [11,
12]. Carbone [13] introduced the use of energy
storage tools in grid-connected PV power plants.
Energy storage batteries (installed in a distributed
manner) can improve the energy production of grid-
connected PV power plants. It therefore represents a
valid alternative to other technical solutions such as
the distributed active MPPTs based on a number of
DC/AC or DC-DC power electronic converters. As
seen in [14, 15], a DC-DC boost converter was
utilized for integrating PV arrays, Fuel Cell (FC)
stack and batteries as input power sources in a
unified structure. In this structure, each switching
cycle of the proposed boost converter is divided into
five switching periods in comparison with the
conventional structure. These switching periods
introduce five different duty ratios for the proposed
boost converter. Because the summation of these
duty ratios should be equal, achieving a high level
output voltage at the DC-link is not possible. Petra
Solar’s Generator Emulation Controls (GEC)
RESEARCH ARTICLE OPEN ACCESS
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technology equipped DG inverters with voltage
support through Volt/VAR drop, low-voltage ride-
through (LVRT), and micro grid forming
capabilities as described in [16]. Khalifa el. al. [17]
proposed a control methodology for interfacing
medium and large PV arrays to the power system
distribution grid. It consists of a PV array in addition
to a power conditioning system for grid interfacing
purposes. The power conditioning system is
composed of a DC-DC boost converter followed by
a current controlled Voltage Source Inverter (VSI).
The system was controlled to inject a clean
sinusoidal current into the grid.
Marinopoulos and Bakas [18] presented
four different system configurations for large scale
PV systems with a typical system configuration of
central inverters and medium voltage transformers as
a reference. Other three alternatives were proposed
including high power DC-DC converters connected
in series or in parallel and cascaded DC/AC
inverters. Taking into account the current
developments in energy storage, new possibilities
for combining PV systems with energy storage units
for large scale power plants are now available. The
output power characteristics of combining both PV
arrays and wind turbines were also introduced. The
perturbation and observation method is used to
accomplish the maximum power point tracking
algorithm for such input sources. The operation
principle of the proposed multi-input inverters is
explained as well.
In this paper, integrating large PV power
plants into the grid via a HVDC link is tested and
validated via a detailed dynamic simulation using
the MATLAB. This well-known package is
considered as an ideal candidate for simulating
complicated power systems with its built-in models
and rich libraries [19]. This integration methodology
facilitates connecting large PV power plants to the
transmission (or sub-transmission) level while
eliminating the possible serious problems regarding
the stability and power control issues. First, the
selected system study is described in the next
section. Then, a thorough investigation study is
presented for investigating the performance of
HVDC link in integrating large PV power plants to
the power grid.
Fig. 1. The schematic diagram of the proposed
system.
II. DESCRIPTION OF THE SELECTED
SIMULATION SYSTEM
In order to investigate the performance of
integrating large PV power plants into the grid, a
38MW PV power plant is considered as a simulation
example. The simulated PV plant is integrated to the
220kV grid system through a HVDC link. A
schematic diagram of overall system is shown in
Fig. 1. It consists of three sub-systems including the
PV sub-system, the HVDC link and the grid. A
typical 3.2MW PV string containing 10 units of a
320kW array is connected as described in Fig. 2. A
Boost DC chopper is dedicated with each 320kW PV
array, where its data was listed in Appendix A. The
boost converter is controlled with a MPPT technique
in order to obtain the maximum power from each
array. The complete simulated PV system consisted
of twelve units of the 3.2 MW string to obtain a
maximum power of 38.4 MW.
Two different integration options of PV
inverter are possible. The first one is with using a
dedicated three-phase inverter with each 3.2MW PV
array. Each inverter uses a regular sampled
asymmetrical-double Edge PWM technique [14].
Then, all inverters are connected to the 0.8kV/25kV
setup-up transformer (/Y connected). Finally, the
system is connected to the transformer of the HVDC
link at the rectifier station as described in Fig. 3a.
Alternatively, a high voltage central inverter is
utilized with the adopted twelve PV arrays and
connected to the 0.8kV/25kV setup-up transformer
and to the HVDC link sub-system as shown in Fig.
3b. This regular sampled asymmetrical-double Edge
PWM technique is used to reduce the harmonics of
the output voltage of the PV system and give the
required ac voltage to the HVDC link at the rectifier
station.
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10 unit*320kW PV string
320kW PV array
320kW PV array
320kW PV array
320kW PV array
Boost DC
Chopper
Upto10units
To
Inverter
Fig. 2. Arrangement of the selected 3.2 MW PV
system.
The converter unit is composed of two 6-
pulse converters connected in series. Both series
converters at the rectifier station are connected via a
smoothing reactor, while another two series ones are
in opposite polarities to form the inverter station.
Each converter is supplied through a (Y-earthed/Y)
and (Y-earthed/) transformers (or via a three
winding transformer with Y-earthed primary and
both secondary's are of Y and respectively). These
transformers act as a 30o phase shift for the AC
voltage of the secondary sides between the Y and
sides to produce the required 12-pulse rectifier
system. Also it can boost the average output voltage
more than the corresponding voltage of the
monopolar-link. In order to reduce the ripples and
the harmonic contents of the orders (5th, 7th, 11th
and 13th) that are accompanied with the voltage
waveforms, dedicated filters can be used. The
ratings of the rectifier station transformer is 40MVA,
50Hz and 22kV/220kV/220kV, while the grid is
with 220 kV and 60Hz. The length of HVDC link is
100km.
3.2MW PV
system
Three-Phase
PWM Inverter
3.2MW PV
system
3.2MW PV
system
3.2MW PV
system
3.2MW PV
system
Upto12units
Three-Phase
PWM Inverter
Three-Phase
PWM Inverter
Three-Phase
PWM Inverter
Upto12units
Three-Phase
PWM Inverter
Y
To HVDC Link
Rectifier Side
(a)
3.2MW PV
system
3.2MW PV
system
3.2MW PV
system
3.2MW PV
system
3.2MW PV
system
Upto12units
Three-Phase
PWM Inverter
To HVDC Link
Rectifier Side
Y
Control of inverter using
regular sampled
asymmetrical-double Edge
PWM
(b)
Fig. 3. (a) Description of the utilized inverters (a)
Configuration of the 38MW PV system with 12-
inverters. (b) Configuration of the 38MW PV system
central inverter.
The control of the power can be achieved
by controlling the firing angles of the rectifier
station, where the rectifier operates in the
rectification mode with 0 90 . The extinction
angle of the inverter station, where the rectifier can
operate in the inverter mode with the firing angle
lying in a range of 90 < <180 . These firing angles
are varied to examine the system performance and
the characteristics of the HVDC system. Then, the
effect of varying the irradiance of the PV power
plant in addition to the change of the angles α and
should be thoroughly investigated.
Rectifier Inverter
R
GridAC1
-RciRcr
Vdorcosα
Vdr
Vdi
+ +
- -
+ +
- -
DCline
Vdoicosγ
Fig. 4. Two terminal DC network.
III. DESCRIPTION OF THE HVDC
CONTROL
A two terminal DC link is shown in Fig. 4
with a rectifier and an inverter. The DC system is
represented by an inductance L and a line resistance
R. The value of the inductance L comprises of the
smoothing reactor(s) and the DC line inductance,
whereas the value of R includes the resistances of
the smoothing reactor(s) and the resistance of the
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DC line etc. [11]. Using Ohm’s law, the DC current
in the DC link depicted in the aforementioned figure
is given by equation (1).
(1)
Where
Vdr is DC-voltage output of the rectifier
Vdi is DC-voltage output of the inverter
R is the DC line resistance.
The power at the rectifier side of DC link is given by
equation (2).
Pdr=Vdr Id (2)
The power at the inverter side of DC link is given by
equation (3).
Pdi=Vdi Id (3)
From the converter theory, the relationships Vd-Id
for the rectifier and the inverter are given by
equations (4) and (5) as,
Vdr = Vdor cos α – Rcr Id (4)
Vdi = Vdoi cos γ - RciId (5)
where Rcr and Rci depend on the overlap
angles at the rectifier and the inverter respectively. If
the overlap angles is zero, their associated voltage
drop equal to zero with overlap, Rcr equals to
3XcrId/ and Rci equals to 3XciId/. Id is the DC
current and Xcr is the commutation reactance (of the
HVDC transformer) at the rectifier. Xci is the
commutation reactance of the inverter.
Vdor = 1.35 VLr is the maximum DC voltage
of rectifier with firing angle =0. VLr is the rms
value of line input voltage of the rectifier, while Vdoi
=1.35 VLi is the maximum DC voltage for the
inverter with γ=0 and VLi is the rms value of line
input voltage of the inverter. Using the equations
describing Vdr and Vdi the DC line current is given
by either one of two options depending upon the
choice of the control mode at the inverter:
Id = (Vdor cos α – Vdoi cos γ) / (Rcr + R - Rci) (6)
The DC output power of the rectifier and
inverter are given by equations 7 and 8. Those
equations shows the power transmitted depending on
the Vdor, Vdoi, , γ and the DC current.
(7)
(8)
The reactive power is absent inside HVDC
link, therefore the using of fixed capacitors and
filters at each AC side to supplemented the reactive
power as mentioned before.
The best choice select γ =180- is to
reduce the voltage drop between output of the
rectifier and the input of inverter inside the HVDC
link.
IV. APPLIED SIMULATION TESTS
Different test cases were applied using the
developed dynamic simulation of the selected
system in MATLAB. A constant solar irradiance
was first considered. Then, the effects of varying the
solar irradiance was extensively investigated. Also,
the influences of a sudden change of the firing angle
was tested. During these tests, the boost converters
were controlled with a MPPT routine with an initial
duty cycle of 0.4. The PV inverter operates at 50Hz
modulation frequency and with a frequency ratio of
33. It has a modulation depth of 0.95 with a regular
sampled asymmetrical-double Edge PWM
technique.
4.1 Constant Solar Irradiance (Constant And
)
The behavior of the simulated system was
illustrated in Fig. 5 at a constant solar irradiance of
1000W/m2 with a firing angle of the rectifier station
of 35o and an extinction angle of 145o. The
frequency of the rectifier station was 50Hz and the
frequency of the inverter station was 60Hz. The
MPPT routine was initiated after 0.5 sec. The
resulting waveforms for the corresponding voltages,
currents, active and reactive power were
demonstrated in Fig. 5(a) generating a total power of
32 MW. Zooming the resulting quantities raises a
pure sinusoidal of both voltages and currents as
shown in Fig. 5(b).
(a)
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(b)
Fig. 5 System performance at the inverter station
(Grid side) with a solar irradiance of 1000W/m2
,
α=35o
and = 145o
. (a) Voltage, current and power
measurement (b) Zoomed outputs at the inverter
station (Grid side) with a solar irradiance of
1000W/m2, α=35o
and = 145o
.
The measured DC voltage and current of
the HVDC link was demonstrated in Fig. 6 having a
DC voltage of 535 kV with approximated current of
60A. Fig. 7 emphasized the performance of the PV
system with a three phase voltage of 22 kV and 36
MW after 0.2 second only. The variation of the
resulting active power at different points of the
simulated system was demonstrated in Fig. 8. The
power at the gird side was reduced by the amount of
the losses in the converter stations, the boost
converter, the PV converter and the DC line with a
total accumulated power losses of 3 MW.
Fig. 6 Rectifier DC voltage, DC current and inverter
dc voltage with a solar irradiance of 1000W/m2,
α=35o
and = 145o
.
Fig. 7 PV performance with a solar irradiance of
1000W/m2
, α=35o
and = 145o
.
Fig. 8 Measured power variation at overall system
with a solar irradiance of 1000W/m2
, α=35o
and
=145o
.
4.2 Sudden Change Of The Solar Irradiance
With Constant α and
The solar irradiance was suddenly changed
from 1000 W/m2 to 600 W/m2 after 0.5 sec. with a
constant α and at 35o and 145o respectively. As
illustrated in Fig. 9, the resulting active power was
remarkably reduced, while the corresponding DC
current of the HVDC link was also reduced from
60A to 25A as illustrated in Fig. 10.
Fig. 9 Performance at the Grid-side for a sudden
change of the solar irradiance from 1000W/m2
to
600W/m2
with constant α and .
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Fig. 10 Performance at the DC link for a sudden
change of the solar irradiance from 1000W/m2
to
600W/m2
with constant α and .
Similarly, Fig. 11 illustrated the
performance of the PV system showing the
reduction of its currents, active power and reactive
power.
4.3 A Sudden Change of With Constant Solar
Irradiance and
In order to investigate the effects of
controlling the firing angle of the rectifier station, α
was suddenly changed from 35o to 50o while
keeping the solar irradiance and the angle constant
at 1000W/m2 and 145o respectively. Fig. 12 shows
the grid performance during this condition, where
both voltages and currents were almost constant. On
the other hand, the resulting active power was
slightly reduced as a function on the firing angle α.
Fig. 13 shows the performance of the HVDC link,
where the DC voltages at rectifier and inverter
stations were not changed. However, the DC current
is reduced depending on the value of firing angle α.
This, therefore, affects the measured power after the
rectifier station as shown in Fig. 14.
Fig. 11 PV system performance for a sudden change
of the solar irradiance from 1000W/m2
to 600W/m2
with constant α and.
Fig. 12 Grid side performance for a sudden change
of α from 35o
to 50o
with constant solar irradiance
and .
Fig. 13 Performance of HVDC link for a sudden
change in α from 350
to 50o
with constant solar
irradiance and.
Fig. 14 Power measurement for a sudden change in
α from 350
to 50o
with constant solar irradiance
and.
The resulting active and reactive power
from the PV system were affected as illustrated in
Fig. 15. Also, a remarkable distortion of the
resulting AC voltage and current was noted
revealing extra harmonic contents.
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Fig. 15 Performance of PV system for a sudden
change in α from 350
to 50o
with constant solar
irradiance and .
4.4 Severe Test with Time Varying Solar
Radiation
The overall PV system was subjected to a
severe test with a time varying solar irradiance
according to the seen profile in Fig. 16. This can be
caused due to severe environmental and weather
conditions. The PV system was subjected to this
varying solar irradiance with a constant firing angles
of the converter and inverter of 35o
and 145o
respectively. Fig. 17 shows the performance of the
PV systems during this condition. As revealed from
the results, the resulting voltages and currents were
changed according to the irradiance variation. Active
and reactive power components were consequently
affected. Fig. 18 illustrated the behavior of the
HVDC link during this condition. The resulting DC
current followed similarly the shape of the irradiance
of PV system, while its DC voltage level was almost
unchanged. As noted from Fig. 19, the measured
power at the grid side followed also the same profile
of the solar irradiance, while its voltage and current
waveforms were almost unchanged
0 0.5 1 1.5 2 2.5 3
200
300
400
500
600
700
800
900
1000
1100
1200
Time (s)
Irradiance(W/m2
)
Fig. 16 Time varying profile of the solar irradiance
of the PV system.
Fig. 17 PV system performance during the time
varying irradiance with α=35o
and = 145o
.
V. CONCLUSION
In this paper, integrating large scale PV
power plants into the power grid via HVDC links
was explored. Different benefits are gained using
this integration methodology including eliminating
stability issues, higher capacity, lower losses, better
voltage profile and better controllability. Also,
utilizing bipolar-HVDC link facilitates integrating
different PV units (even with different frequency)
together (with different frequency of the grid) to the
grid. A large PV example of a 36 MW was
considered as a simulation example. Different
investigation tests including the variations of the
solar radiance and the converter control angle. A
MPPT routine was utilized for maximizing the
performance of large grid PVs. Controlling the firing
angles of the rectidier and inverter (α and ) helps
supervising the integration profile effectively.
Fig. 18 HVDC link performance during the time
varying irradiance with α=35o
and = 145o
.
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Fig. 19 Grid side performance during the time
varying irradiance with α=35o
and = 145o
.
Appendix: PV String (32kw)
The type of the module: Sun-Power SPR-30 SWHT,
Number of cells per module=96, Number of series-
connected modules per string=35 and number of
parallel strings 330.
ACKNOWLEDGEMENTS
The authors would like to thank Deanship of
Scientific Research at Umm Al-Qura University
(UQU), Saudi Arabia for the financial Support
(Project ID: 43408007).
REFERENCES
[1]. Singh D, Sharma N, Soo Y, Jarial R. Global
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