Precise and low-latency information transmission through communication systems is essential in the Industrial Internet of Things(IIoT).However,in an industrial system,there is always a coupling relationship between th...Precise and low-latency information transmission through communication systems is essential in the Industrial Internet of Things(IIoT).However,in an industrial system,there is always a coupling relationship between the control and communication components.To improve the system's overall performance,exploring the co-design of communication and control systems is crucial.In this work,we propose a new metric±Age of Loop Information with Flexible Transmission(AoLI-FT),which dynamically adjusts the maximum number of uplink(UL)and downlink(DL)transmission rounds,thus enhancing reliability while ensuring timeliness.Our goal is to explore the relationship between AoLI-FT,reliability,and control convergence rate,and to design optimal blocklengths for UL and DL that achieve the desired control convergence rate.To address this issue,we first derive a closed-form expression for the upper bound of AoLI-FT.Subsequently,we establish a relationship between communication reliability and control convergence rates using a Lyapunov-like function.Finally,we introduce an iterative alternating algorithm to determine the optimal communication and control parameters.The numerical results demonstrate the significant performance advantages of our proposed communication and control co-design strategy in terms of latency and control cost.展开更多
After the digital revolution, the power system security becomes an important issue and it urges the power producers to maintain a well secured system in order to supply a quality power to the end users. This paper pre...After the digital revolution, the power system security becomes an important issue and it urges the power producers to maintain a well secured system in order to supply a quality power to the end users. This paper presents an integrated Corrective Security Constrained Optimal Power Flow (CSCOPF) with Flexible Transmission Line Impedance (FTLI) to enhance the power system security. The corrective approach of SCOPF is chosen, because it allows the corrective equipment to bring back the system to a stable operating point and hence, it offers high flexibility and better economics. The concept of FTLI arises from the ability of FACTS devices such as Thyristor Controlled Series Capacitor (TCSC), which can vary the line reactance to a certain extent. An enhanced security can be achieved by incorporating FTLI into the CSCOPF problem, since the power flow in a system is highly dependent on the line reactance. FTLI based CSCOPF can reduce the amount of rescheduling of generators, but it will result in an increased number of variables and thus, the complexity to the optimization process is increased. This highly complex problem is solved by using nonlinear programming. The AC based OPF model is preferred, since the corrective security actions require highly accurate solutions. IEEE 30 bus system is used to test the proposed scheme and the results are compared with the traditional CSCOPF. It can be seen that the proposed idea provides a notable improvement in the reduction of cost incurred for restoring the system security.展开更多
Determining the fault location using conventional impedance based distance relay in the presence of FACTS controllers is a challenging task in a transmission line. A new distance protection method is developed to loca...Determining the fault location using conventional impedance based distance relay in the presence of FACTS controllers is a challenging task in a transmission line. A new distance protection method is developed to locate the fault in a transmission line compensated with STATCOM with simple calculations. The proposed protection method considers the STATCOM injected/absorbed current to correct the fault loop apparent impedance and accordingly calculates the actual distance to the fault location. The comprehensive equations needed for apparent impedance calculation are also outlined and the performance is evaluated and tested with a typical 400 KV transmission system for different fault types and locations using MATLAB/SIMULINK software. The evaluation results indicate that the new protection method effectively estimates the exact fault location by mitigating the impact of STATCOM on distance relay performance with error less than 0.3%.展开更多
This paper introduces the working principle of HVDC control and protection system. And the paper summarizes the flexible HVDC technology features and application fields and describes the composition and software intel...This paper introduces the working principle of HVDC control and protection system. And the paper summarizes the flexible HVDC technology features and application fields and describes the composition and software intelligent flexible HVDC control and protection system configuration. Finally, the simulation results are also given, experimental results show： HVDC flexible intelligent control and protection has a good control effect in the steady state and transient process, suitable for practical engineering application.展开更多
The challenges and the path towards a(more)electronic transmission and distribution(eT&D)is presented in this paper.The challenges are first identified together with key stakeholders in the drive for grid moderniz...The challenges and the path towards a(more)electronic transmission and distribution(eT&D)is presented in this paper.The challenges are first identified together with key stakeholders in the drive for grid modernization.A fundamental question is then asked about the investment priority.Six basic characteristics are reviewed,leading to the composition of structured microgrids as the basic functional cell of a modern grid.One example of fractal radial structure and one fractal meshed structure are presented.The likely evolution path is then proposed together with basic technology sets.Specific foundation technologies are discussed in detail,including adiabatic power conversion,3MC technology,medium voltage conversion,distribution-level electronic power transformer and FACTs hardware integration,and back-to-back converters as a universal interconnect element.The rapidly emerging on-wire sensing technology is also discussed.It is pointed out that the distribution-level large electronic power transformer will provide a key component to enable hybrid ac/dc grid flow control and ancillary support for a flexible electronic transmission and distribution(eT&D)systems.展开更多
The health monitoring for large-scale structures need to resolve a large number of difficulties,such as the data transmission and distributing information handling.To solve these problems,the technology of multi-agent...The health monitoring for large-scale structures need to resolve a large number of difficulties,such as the data transmission and distributing information handling.To solve these problems,the technology of multi-agent is a good candidate to be used in the field of structural health monitoring.A structural health monitoring system architecture based on multi-agent technology is proposed.The measurement system for aircraft airfoil is designed with FBG,strain gage,and corresponding signal processing circuit.The experiment to determine the location of the concentrate loading on the structure is carried on with the system combined with technologies of pattern recognition and multi-agent.The results show that the system can locate the concentrate loading of the aircraft airfoil at the accuracy of 91.2%.展开更多
Based on its prototype of machine-isolator-foundation systems, a theoretical model for dynamic coupled linear system is established, in which both the passive and active control factors are considered. Power flow is u...Based on its prototype of machine-isolator-foundation systems, a theoretical model for dynamic coupled linear system is established, in which both the passive and active control factors are considered. Power flow is used as the cost function to evaluate the isolation effectiveness. And the transmission of vibratory power flow from a vibrating rigid body into a simply supported thin panel through passive isolators and actuators is investigated numerically. The active control strategy is summarized in the conclusion.展开更多
This paper deals with power transfer capability enhancement using two common Flexible Alternating Current Transmission Systems （FACTS） devices, Thyristor Controlled Series Capacitor （TCSC） and Static Var Compensat...This paper deals with power transfer capability enhancement using two common Flexible Alternating Current Transmission Systems （FACTS） devices, Thyristor Controlled Series Capacitor （TCSC） and Static Var Compensator （SVC）. For this purpose, at first the optimal place of TCSC and SVC is investigated and the optimal size is determined. At the end, a comparison is made between the two FACTS devices. For calculating Available Transfer Capability （ATC）, Repeated Power-Flow （RPF） rule used, and the network limitations such as voltage, stability, thermal capacity, and power generation limits are taken into consideration. The proposed algorithm is run on a sample network. Results show effectiveness of TCSC in situations where the thermal limit is the dominant limitation of the network. In such situations, SVC is almost useless. It was also seen that under conditions of voltage limitations, both elements are helpful for the enhancement of ATC.展开更多
A three-phase to single-phase modular multilevel converter based advanced co-phase traction power supply(MMC-ACTPS) system is an effective structure to address the concerns of phase splitting and poor power quality of...A three-phase to single-phase modular multilevel converter based advanced co-phase traction power supply(MMC-ACTPS) system is an effective structure to address the concerns of phase splitting and poor power quality of the conventional electrified railway. Due to the large number of MMCACTPS system modules, I/O resources and computing speed have high requirements on processors. Moreover, the module capacitor balance is challenging because the sorting time is too long when the traditional sorting algorithm for voltage balance is used. To solve the above issues, a digital implementation scheme of flexible power control strategy for three-phase to single-phase MMC-ACTPS system based on field programmable gate array(FPGA), which has sufficient I/O resources, has been proposed. Due to the parallel execution characteristics of the FPGA, the execution time of the controller and the modulator can be greatly reduced compared with a digital signal processor(DSP) + FPGA or DSpace. In addition, an improved sorting algorithm is proposed to reduce the sorting time and the implementation steps are analyzed. Finally, simulation and experimental results are presented to demonstrate the effectiveness and correctness of the proposed control strategy.展开更多
In large inter connected power systems, inter-area oscillations are turned to be a severe problem. Hence inter-area oscillations cause severe problems like damage to generators, reduce the power transfer capability of...In large inter connected power systems, inter-area oscillations are turned to be a severe problem. Hence inter-area oscillations cause severe problems like damage to generators, reduce the power transfer capability of transmission lines, increase wear and tear on network components, increase line losses etc. This paper is to maintain the stability of system by damping inter-area oscillations. Implementation of new equipment consists of high power electronics based technologies such as FACTs and proper controller design has become an essential to provide better damping performance than Power System Stabilizer (PSS). With development of Wide Area Measurement System (WAMS), remote signals have become as feedback signals to design Wide Area Damping Controller (WADC) for FACTs devices. In this work, POD is applied to both SVC and SSSC. Simulation studies are carried out in Power System Analysis Toolbox (PSAT) environment to evaluate the effectiveness of the FACTs controller in a large area power system. Results show that extensive analysis of FACTs controller for improving stability of system.展开更多
As one of the new generation flexible AC transmission systems(FACTS)devices,the interline power flow controller(IPFC)has the significant advantage of simultaneously regulating the power flow of multiple lines.Neverthe...As one of the new generation flexible AC transmission systems(FACTS)devices,the interline power flow controller(IPFC)has the significant advantage of simultaneously regulating the power flow of multiple lines.Nevertheless,how to choose the appropriate location for the IPFC converters has not been discussed thoroughly.To solve this problem,this paper proposes a novel location method for IPFC using entropy theory.To clarify IPFC’s impact on system power flow,its operation mechanism and control strategies of different types of serial converters are discussed.Subsequently,to clarify the system power flow characteristic suitable for device location analysis,the entropy concept is introduced.In this process,the power flow distribution entropy index is used as an optimization index.Using this index as a foundation,the power flow transfer entropy index is also generated and proposed for the IPFC location determination study.Finally,electromechanical electromagnetic hybrid simulations based on ADPSS are implemented for validation.These are tested in a practical power grid with over 800 nodes.A modular multilevel converter(MMC)-based IPFC electromagnetic model is also established for precise verification.The results show that the proposed method can quickly and efficiently complete optimized IPFC location and support IPFC to determine an optimal adjustment in the N-1 fault cases.展开更多
The main objective of this paper is three-fold.First, to provide an overview of the current status of the power electronics technology, one of the key actors in the upcoming smart grid paradigm enabling maximum power ...The main objective of this paper is three-fold.First, to provide an overview of the current status of the power electronics technology, one of the key actors in the upcoming smart grid paradigm enabling maximum power throughputs and near-instantaneous control of voltages and currents in all links of the power system chain. Second, to provide a bridge between the power systems and the power electronic communities, in terms of their differing appreciation of how these devices perform when connected to the power grid. Third, to discuss on the role that the power electronics technology will play in supporting the aims and objectives of future decarbonized power systems. This paper merges the equipment, control techniques and methods used in flexible alternating current transmission systems(FACTS) and high voltage direct transmission(HVDC) equipment to enable a single, coherent approach to address a specific power system problem, using ‘best of breed’ solutions bearing in mind technical, economic and environmental issues.展开更多
Flexible AC transmission systems(FACTS)devices can effectively optimize the distribution of power flow.Power flow entropy can be applied as a measure of load distribution.In this paper,a method is proposed to optimize...Flexible AC transmission systems(FACTS)devices can effectively optimize the distribution of power flow.Power flow entropy can be applied as a measure of load distribution.In this paper,a method is proposed to optimize the distribution of power flow with the coordination of multi-type FACTS devices and establishes the corresponding mathematical models.The modified group searcher optimization(GSO)algorithm is proposed,in which the angle search is combined with chaotic search model to avoid jumping into local optimization.Compared with the different optimal allocation of multi-FACTS devices,the optimal allocation of multi-FACTS devices is achieved under the economic constraints.The locations obtained by this method can achieve the purpose of balancing power flow and enhancing the system performances.The simulations are demonstrated in an IEEE 118-bus power system with two classical types of FACTS,namely static var compensator(SVC)and thyristor controlled series Compensator(TCSC).The simulation results show that the proposed method is feasible and effective.展开更多
The popularity of insulated gate bipolar transistors(IGBTs)for use in high-voltage direct current(HVDC)transmission and flexible AC transmission systems(FACTS)is increasing.Unfortunately,for these applications wire-bo...The popularity of insulated gate bipolar transistors(IGBTs)for use in high-voltage direct current(HVDC)transmission and flexible AC transmission systems(FACTS)is increasing.Unfortunately,for these applications wire-bond IGBT technology has a number of shortcomings,such as insufficient current ratings for the most powerful schemes,and inability to fail to short-circuit.Press-pack IGBT technology,conversely,offers increased current ratings,and an inherent short-circuit failure mode,making it a more attractive choice for HVDC and FACTS.However,the design and manufacture of these devices requires a comprehensive understanding of the unique technical challenges,which differ markedly from those for wirebond modules or traditional pressure contact devices.Specific challenges include providing a high degree of mechanical protection for the IGBT chip against normal operating stresses.Furthermore,it is essential to achieve uniform contact pressure across each chip surface to ensure optimum performance.To achieve this,manufacturers have designed products that use rigid copper electrodes manufactured to tighter tolerances than for other pressure contact devices,such as thyristors,and products that use compliant electrodes,incorporating spring assemblies.Dynex is in the advanced stages of development of press-pack IGBT technology with demonstrated robust solutions for the technical challenges outlined in this paper.Design success has been achieved through the use of state-of-the-art simulations in conjunction with a long history of manufacturing expertise for bipolar and IGBT products.Finally,multiple press-pack IGBT variants are currently undergoing evaluation tests prior to product release.展开更多
Relieving network congestions is a critical goal for the safe and flexible operation of modern power systems, especially in the presence of intermittent renewables or distributed generation. This paper deals with the ...Relieving network congestions is a critical goal for the safe and flexible operation of modern power systems, especially in the presence of intermittent renewables or distributed generation. This paper deals with the real-time coordinated operation of distributed static series compensators(DSSCs) to remove network congestions by suitable modifications of the branch reactance. Several objective functions are considered and discussed to minimize the number of the devices involved in the control actions, the total losses or the total reactive power exchanged, leading to a non-convex mixed-integer non-linear programming problem. Then, a heuristic methodology combining the solution of a regular NLP with k-means clustering algorithm is proposed to get rid of the binary variables, in an attempt to reduce the computational cost. The proposed coordinated operation strategy of the DSSCs is tested on several benchmark systems, providing feasible and sufficiently optimal solutions in a reasonable time frame for practical systems.展开更多
In power system studies, congestion in trans- mission lines and utilization of flexible alternating current transmission system （FACTS） devices are closely associated. These devices are very important due to their r...In power system studies, congestion in trans- mission lines and utilization of flexible alternating current transmission system （FACTS） devices are closely associated. These devices are very important due to their role in power delivery system enhancement. It is to be noted that the generation companies can exercise their market power which depends on the line flows, line constraints, generators＇ location and its share to the individual loads. This issue cannot be overlooked as it creates monopoliness which is against the deregulated market policy. The objective of this paper is to study the impact of market power when FACTS devices like thyristor controlled switching capacitor （TCSC） and thyristor controlled phase angle regulator （TCPAR） are used under steady state operation. The market power is determined using nodal must-run share （NMRS） index for the standard IEEE 14- bus system with and without the above FACTS devices and the results obtained are compared. All the above simula- tions are conducted in a MATLAB 7.9-R2009b environment.展开更多
This paper presents an efficient interactive differential evolution ODE） to solve the multi-objective security environmental/economic dispatch （SEED） pro- blem considering multi shunt flexible AC transmission syst...This paper presents an efficient interactive differential evolution ODE） to solve the multi-objective security environmental/economic dispatch （SEED） pro- blem considering multi shunt flexible AC transmission system （FACTS） devices. Two sub problems are proposed. The first one is related to the active power planning to minimize the combined total fuel cost and emissions, while the second is a reactive power planning （RPP） using multi shunt FACTS device based static VAR compensator （SVC） installed at specified buses to make fine corrections to the voltage deviation, voltage phase profiles and reactive power violation. The migration operation inspired from biogeography-based optimization （BBO） algorithm is newly introduced in the proposed approach, thereby effectively exploring and exploiting promising regions in a space search by creating dynamically new efficient partitions. This new mechanism based migration between individuals from different subsystems makes the initial partitions to react more by changing experiences. To validate the robustness of the proposed approach, the proposed algorithm is tested on the Algerian 59-bus electrical network and on a large system, 40 generating units considering valve-point loading effect. Comparison of the results with recent global optimization methods show the superiority of the proposed IDE approach and confirm its potential for solving practical optimal power flow in terms of solution quality and convergence characteristics.展开更多
This paper presents a novel approach to find optimum locations and capacity of flexible alternating current transmission system (FACTS) devices in a power system using a multi-objective optimization function. Thyristo...This paper presents a novel approach to find optimum locations and capacity of flexible alternating current transmission system (FACTS) devices in a power system using a multi-objective optimization function. Thyristor controlled series compensators (TCSCs) and static var compensators (SVCs) are the utilized FACTS devices. Our objectives are active power loss reduction, newly introduced FACTS devices cost reduction, voltage deviation reduction, and increase on the robustness of the security margin against voltage collapse. The operational and controlling constraints, as well as load constraints, were considered in the optimum allocation. A goal attainment method based on the genetic algorithm (GA) was used to approach the global optimum. The estimated annual load profile was utilized in a sequential quadratic programming (SQP) optimization sub-problem to the optimum siting and sizing of FACTS devices. Fars Regional Electric Network was selected as a practical system to validate the performance and effectiveness of the proposed method. The entire investment of the FACTS devices was paid off and an additional 2.4% savings was made. The cost reduction of peak point power generation implies that power plant expansion can be postponed.展开更多
基金supported in part by the National Key R&D Program of China under Grant 2024YFE0200500in part by the Guangdong Basic and Applied Basic Research Foundation under Grant 2024A1515012615in part by the Department of Science and Technology of Guangdong Province under Grant 2021QN02X491。
文摘Precise and low-latency information transmission through communication systems is essential in the Industrial Internet of Things(IIoT).However,in an industrial system,there is always a coupling relationship between the control and communication components.To improve the system's overall performance,exploring the co-design of communication and control systems is crucial.In this work,we propose a new metric±Age of Loop Information with Flexible Transmission(AoLI-FT),which dynamically adjusts the maximum number of uplink(UL)and downlink(DL)transmission rounds,thus enhancing reliability while ensuring timeliness.Our goal is to explore the relationship between AoLI-FT,reliability,and control convergence rate,and to design optimal blocklengths for UL and DL that achieve the desired control convergence rate.To address this issue,we first derive a closed-form expression for the upper bound of AoLI-FT.Subsequently,we establish a relationship between communication reliability and control convergence rates using a Lyapunov-like function.Finally,we introduce an iterative alternating algorithm to determine the optimal communication and control parameters.The numerical results demonstrate the significant performance advantages of our proposed communication and control co-design strategy in terms of latency and control cost.
文摘After the digital revolution, the power system security becomes an important issue and it urges the power producers to maintain a well secured system in order to supply a quality power to the end users. This paper presents an integrated Corrective Security Constrained Optimal Power Flow (CSCOPF) with Flexible Transmission Line Impedance (FTLI) to enhance the power system security. The corrective approach of SCOPF is chosen, because it allows the corrective equipment to bring back the system to a stable operating point and hence, it offers high flexibility and better economics. The concept of FTLI arises from the ability of FACTS devices such as Thyristor Controlled Series Capacitor (TCSC), which can vary the line reactance to a certain extent. An enhanced security can be achieved by incorporating FTLI into the CSCOPF problem, since the power flow in a system is highly dependent on the line reactance. FTLI based CSCOPF can reduce the amount of rescheduling of generators, but it will result in an increased number of variables and thus, the complexity to the optimization process is increased. This highly complex problem is solved by using nonlinear programming. The AC based OPF model is preferred, since the corrective security actions require highly accurate solutions. IEEE 30 bus system is used to test the proposed scheme and the results are compared with the traditional CSCOPF. It can be seen that the proposed idea provides a notable improvement in the reduction of cost incurred for restoring the system security.
文摘Determining the fault location using conventional impedance based distance relay in the presence of FACTS controllers is a challenging task in a transmission line. A new distance protection method is developed to locate the fault in a transmission line compensated with STATCOM with simple calculations. The proposed protection method considers the STATCOM injected/absorbed current to correct the fault loop apparent impedance and accordingly calculates the actual distance to the fault location. The comprehensive equations needed for apparent impedance calculation are also outlined and the performance is evaluated and tested with a typical 400 KV transmission system for different fault types and locations using MATLAB/SIMULINK software. The evaluation results indicate that the new protection method effectively estimates the exact fault location by mitigating the impact of STATCOM on distance relay performance with error less than 0.3%.
文摘This paper introduces the working principle of HVDC control and protection system. And the paper summarizes the flexible HVDC technology features and application fields and describes the composition and software intelligent flexible HVDC control and protection system configuration. Finally, the simulation results are also given, experimental results show： HVDC flexible intelligent control and protection has a good control effect in the steady state and transient process, suitable for practical engineering application.
文摘The challenges and the path towards a(more)electronic transmission and distribution(eT&D)is presented in this paper.The challenges are first identified together with key stakeholders in the drive for grid modernization.A fundamental question is then asked about the investment priority.Six basic characteristics are reviewed,leading to the composition of structured microgrids as the basic functional cell of a modern grid.One example of fractal radial structure and one fractal meshed structure are presented.The likely evolution path is then proposed together with basic technology sets.Specific foundation technologies are discussed in detail,including adiabatic power conversion,3MC technology,medium voltage conversion,distribution-level electronic power transformer and FACTs hardware integration,and back-to-back converters as a universal interconnect element.The rapidly emerging on-wire sensing technology is also discussed.It is pointed out that the distribution-level large electronic power transformer will provide a key component to enable hybrid ac/dc grid flow control and ancillary support for a flexible electronic transmission and distribution(eT&D)systems.
基金supported by the Key Program of the National Science Foundation of China(50830201)Aviation Research Foundation(20060952)+1 种基金the National High Technology Research and Development of China(2007AA03Z117)the Natural Science Foundation of Jiansu Province(08kjd560009)
文摘The health monitoring for large-scale structures need to resolve a large number of difficulties,such as the data transmission and distributing information handling.To solve these problems,the technology of multi-agent is a good candidate to be used in the field of structural health monitoring.A structural health monitoring system architecture based on multi-agent technology is proposed.The measurement system for aircraft airfoil is designed with FBG,strain gage,and corresponding signal processing circuit.The experiment to determine the location of the concentrate loading on the structure is carried on with the system combined with technologies of pattern recognition and multi-agent.The results show that the system can locate the concentrate loading of the aircraft airfoil at the accuracy of 91.2%.
文摘Based on its prototype of machine-isolator-foundation systems, a theoretical model for dynamic coupled linear system is established, in which both the passive and active control factors are considered. Power flow is used as the cost function to evaluate the isolation effectiveness. And the transmission of vibratory power flow from a vibrating rigid body into a simply supported thin panel through passive isolators and actuators is investigated numerically. The active control strategy is summarized in the conclusion.
文摘This paper deals with power transfer capability enhancement using two common Flexible Alternating Current Transmission Systems （FACTS） devices, Thyristor Controlled Series Capacitor （TCSC） and Static Var Compensator （SVC）. For this purpose, at first the optimal place of TCSC and SVC is investigated and the optimal size is determined. At the end, a comparison is made between the two FACTS devices. For calculating Available Transfer Capability （ATC）, Repeated Power-Flow （RPF） rule used, and the network limitations such as voltage, stability, thermal capacity, and power generation limits are taken into consideration. The proposed algorithm is run on a sample network. Results show effectiveness of TCSC in situations where the thermal limit is the dominant limitation of the network. In such situations, SVC is almost useless. It was also seen that under conditions of voltage limitations, both elements are helpful for the enhancement of ATC.
基金supported in part by the National Rail Transportation Electrification and Automation Engineering Technology Research Center (No.NEEC-2019-A04)in part by the National Key R&D Program of China (No.2021YFB2601500)+1 种基金in part by the National Natural Science Foundation of China (No.52077183)the National Science Foundation for Young Scientists of China (No.52207138)。
文摘A three-phase to single-phase modular multilevel converter based advanced co-phase traction power supply(MMC-ACTPS) system is an effective structure to address the concerns of phase splitting and poor power quality of the conventional electrified railway. Due to the large number of MMCACTPS system modules, I/O resources and computing speed have high requirements on processors. Moreover, the module capacitor balance is challenging because the sorting time is too long when the traditional sorting algorithm for voltage balance is used. To solve the above issues, a digital implementation scheme of flexible power control strategy for three-phase to single-phase MMC-ACTPS system based on field programmable gate array(FPGA), which has sufficient I/O resources, has been proposed. Due to the parallel execution characteristics of the FPGA, the execution time of the controller and the modulator can be greatly reduced compared with a digital signal processor(DSP) + FPGA or DSpace. In addition, an improved sorting algorithm is proposed to reduce the sorting time and the implementation steps are analyzed. Finally, simulation and experimental results are presented to demonstrate the effectiveness and correctness of the proposed control strategy.
文摘In large inter connected power systems, inter-area oscillations are turned to be a severe problem. Hence inter-area oscillations cause severe problems like damage to generators, reduce the power transfer capability of transmission lines, increase wear and tear on network components, increase line losses etc. This paper is to maintain the stability of system by damping inter-area oscillations. Implementation of new equipment consists of high power electronics based technologies such as FACTs and proper controller design has become an essential to provide better damping performance than Power System Stabilizer (PSS). With development of Wide Area Measurement System (WAMS), remote signals have become as feedback signals to design Wide Area Damping Controller (WADC) for FACTs devices. In this work, POD is applied to both SVC and SSSC. Simulation studies are carried out in Power System Analysis Toolbox (PSAT) environment to evaluate the effectiveness of the FACTs controller in a large area power system. Results show that extensive analysis of FACTs controller for improving stability of system.
基金supported by the Natural Science Foundation of Sichuan Province of China(No.2022NSFSC0262)the Fundamental Research Funds for the Central Universities(No.2022SCU12005).
文摘As one of the new generation flexible AC transmission systems(FACTS)devices,the interline power flow controller(IPFC)has the significant advantage of simultaneously regulating the power flow of multiple lines.Nevertheless,how to choose the appropriate location for the IPFC converters has not been discussed thoroughly.To solve this problem,this paper proposes a novel location method for IPFC using entropy theory.To clarify IPFC’s impact on system power flow,its operation mechanism and control strategies of different types of serial converters are discussed.Subsequently,to clarify the system power flow characteristic suitable for device location analysis,the entropy concept is introduced.In this process,the power flow distribution entropy index is used as an optimization index.Using this index as a foundation,the power flow transfer entropy index is also generated and proposed for the IPFC location determination study.Finally,electromechanical electromagnetic hybrid simulations based on ADPSS are implemented for validation.These are tested in a practical power grid with over 800 nodes.A modular multilevel converter(MMC)-based IPFC electromagnetic model is also established for precise verification.The results show that the proposed method can quickly and efficiently complete optimized IPFC location and support IPFC to determine an optimal adjustment in the N-1 fault cases.
基金supported by Spanish Ministry of Economy and Competitiveness and Junta de Andalucía through the projects ENE2014-54115-R and TEP-7411
文摘The main objective of this paper is three-fold.First, to provide an overview of the current status of the power electronics technology, one of the key actors in the upcoming smart grid paradigm enabling maximum power throughputs and near-instantaneous control of voltages and currents in all links of the power system chain. Second, to provide a bridge between the power systems and the power electronic communities, in terms of their differing appreciation of how these devices perform when connected to the power grid. Third, to discuss on the role that the power electronics technology will play in supporting the aims and objectives of future decarbonized power systems. This paper merges the equipment, control techniques and methods used in flexible alternating current transmission systems(FACTS) and high voltage direct transmission(HVDC) equipment to enable a single, coherent approach to address a specific power system problem, using ‘best of breed’ solutions bearing in mind technical, economic and environmental issues.
基金This work was funded by National Science and Technology Support Program of China(2010BAE00816).
文摘Flexible AC transmission systems(FACTS)devices can effectively optimize the distribution of power flow.Power flow entropy can be applied as a measure of load distribution.In this paper,a method is proposed to optimize the distribution of power flow with the coordination of multi-type FACTS devices and establishes the corresponding mathematical models.The modified group searcher optimization(GSO)algorithm is proposed,in which the angle search is combined with chaotic search model to avoid jumping into local optimization.Compared with the different optimal allocation of multi-FACTS devices,the optimal allocation of multi-FACTS devices is achieved under the economic constraints.The locations obtained by this method can achieve the purpose of balancing power flow and enhancing the system performances.The simulations are demonstrated in an IEEE 118-bus power system with two classical types of FACTS,namely static var compensator(SVC)and thyristor controlled series Compensator(TCSC).The simulation results show that the proposed method is feasible and effective.
文摘The popularity of insulated gate bipolar transistors(IGBTs)for use in high-voltage direct current(HVDC)transmission and flexible AC transmission systems(FACTS)is increasing.Unfortunately,for these applications wire-bond IGBT technology has a number of shortcomings,such as insufficient current ratings for the most powerful schemes,and inability to fail to short-circuit.Press-pack IGBT technology,conversely,offers increased current ratings,and an inherent short-circuit failure mode,making it a more attractive choice for HVDC and FACTS.However,the design and manufacture of these devices requires a comprehensive understanding of the unique technical challenges,which differ markedly from those for wirebond modules or traditional pressure contact devices.Specific challenges include providing a high degree of mechanical protection for the IGBT chip against normal operating stresses.Furthermore,it is essential to achieve uniform contact pressure across each chip surface to ensure optimum performance.To achieve this,manufacturers have designed products that use rigid copper electrodes manufactured to tighter tolerances than for other pressure contact devices,such as thyristors,and products that use compliant electrodes,incorporating spring assemblies.Dynex is in the advanced stages of development of press-pack IGBT technology with demonstrated robust solutions for the technical challenges outlined in this paper.Design success has been achieved through the use of state-of-the-art simulations in conjunction with a long history of manufacturing expertise for bipolar and IGBT products.Finally,multiple press-pack IGBT variants are currently undergoing evaluation tests prior to product release.
基金supported by the Spanish Ministry of Economy and Competitiveness (No. ENE2017-84813-R)the CERVERA research program of the Spanish Industrial and Technological Development Centre (CDTI) under the research project HySGrid+(CER-20191019)Junta de Andalucía (No. P18-TP-3655)。
文摘Relieving network congestions is a critical goal for the safe and flexible operation of modern power systems, especially in the presence of intermittent renewables or distributed generation. This paper deals with the real-time coordinated operation of distributed static series compensators(DSSCs) to remove network congestions by suitable modifications of the branch reactance. Several objective functions are considered and discussed to minimize the number of the devices involved in the control actions, the total losses or the total reactive power exchanged, leading to a non-convex mixed-integer non-linear programming problem. Then, a heuristic methodology combining the solution of a regular NLP with k-means clustering algorithm is proposed to get rid of the binary variables, in an attempt to reduce the computational cost. The proposed coordinated operation strategy of the DSSCs is tested on several benchmark systems, providing feasible and sufficiently optimal solutions in a reasonable time frame for practical systems.
文摘In power system studies, congestion in trans- mission lines and utilization of flexible alternating current transmission system （FACTS） devices are closely associated. These devices are very important due to their role in power delivery system enhancement. It is to be noted that the generation companies can exercise their market power which depends on the line flows, line constraints, generators＇ location and its share to the individual loads. This issue cannot be overlooked as it creates monopoliness which is against the deregulated market policy. The objective of this paper is to study the impact of market power when FACTS devices like thyristor controlled switching capacitor （TCSC） and thyristor controlled phase angle regulator （TCPAR） are used under steady state operation. The market power is determined using nodal must-run share （NMRS） index for the standard IEEE 14- bus system with and without the above FACTS devices and the results obtained are compared. All the above simula- tions are conducted in a MATLAB 7.9-R2009b environment.
文摘This paper presents an efficient interactive differential evolution ODE） to solve the multi-objective security environmental/economic dispatch （SEED） pro- blem considering multi shunt flexible AC transmission system （FACTS） devices. Two sub problems are proposed. The first one is related to the active power planning to minimize the combined total fuel cost and emissions, while the second is a reactive power planning （RPP） using multi shunt FACTS device based static VAR compensator （SVC） installed at specified buses to make fine corrections to the voltage deviation, voltage phase profiles and reactive power violation. The migration operation inspired from biogeography-based optimization （BBO） algorithm is newly introduced in the proposed approach, thereby effectively exploring and exploiting promising regions in a space search by creating dynamically new efficient partitions. This new mechanism based migration between individuals from different subsystems makes the initial partitions to react more by changing experiences. To validate the robustness of the proposed approach, the proposed algorithm is tested on the Algerian 59-bus electrical network and on a large system, 40 generating units considering valve-point loading effect. Comparison of the results with recent global optimization methods show the superiority of the proposed IDE approach and confirm its potential for solving practical optimal power flow in terms of solution quality and convergence characteristics.
文摘This paper presents a novel approach to find optimum locations and capacity of flexible alternating current transmission system (FACTS) devices in a power system using a multi-objective optimization function. Thyristor controlled series compensators (TCSCs) and static var compensators (SVCs) are the utilized FACTS devices. Our objectives are active power loss reduction, newly introduced FACTS devices cost reduction, voltage deviation reduction, and increase on the robustness of the security margin against voltage collapse. The operational and controlling constraints, as well as load constraints, were considered in the optimum allocation. A goal attainment method based on the genetic algorithm (GA) was used to approach the global optimum. The estimated annual load profile was utilized in a sequential quadratic programming (SQP) optimization sub-problem to the optimum siting and sizing of FACTS devices. Fars Regional Electric Network was selected as a practical system to validate the performance and effectiveness of the proposed method. The entire investment of the FACTS devices was paid off and an additional 2.4% savings was made. The cost reduction of peak point power generation implies that power plant expansion can be postponed.
