Aiming at the challenge of complex load balancing coordination for a three-phase four-leg(3P4L)based multi-ended low voltage flexible DC distribution system(M-LVDC)considering unbalanced power compensation,this paper ...Aiming at the challenge of complex load balancing coordination for a three-phase four-leg(3P4L)based multi-ended low voltage flexible DC distribution system(M-LVDC)considering unbalanced power compensation,this paper proposes a phase-split power decoupling unbalanced compensation strategy based load balancing strategy for 3P4L based M-LVDC.Firstly,the topology and operation principle of the 3P4L-based M-LVDC system is introduced,and quasi-proportional resonant(QPR)based phase-split power current control for the 3P4L converter is proposed.Secondly,a load-balancing control strategy considering unbalanced compensation for 3P4L-based MLVDC is presented,in which the control diagrams for each 3P4L-based converter are detailed.The core idea of the proposed strategy is to comprehensively consider the imbalance compensation and load rate balancing between the two areas to calculate the split-phase power and current reference values of each 3P4L converter and achieve the static error-free tracking of the reference values through the QPR current inner-loop control.These reference values are then tracked with zero steady-state error using QPR current inner-loop control.Finally,the effectiveness of the proposed control strategy is verified through a 3P4L M-LVDC case study conducted on the PSCAD/EMTDC software.Theresults indicate that the proposed method not only can reduce the three-phase imbalance degrees from>20% to<0.5%,but also achieve excellent balanced load rates,with the load-rate difference smaller than 1.5%.展开更多
As the large-scale development of wind farms(WFs)progresses,the connection ofWFs to the regional power grid is evolving from the conventional receiving power grid to the sending power grid with a high proportion of wi...As the large-scale development of wind farms(WFs)progresses,the connection ofWFs to the regional power grid is evolving from the conventional receiving power grid to the sending power grid with a high proportion of wind power(WP).Due to the randomness of WP output,higher requirements are put forward for the voltage stability of each node of the regional power grid,and various reactive power compensation devices(RPCDs)need to be rationally configured to meet the stable operation requirements of the system.This paper proposes an optimal configuration method for multi-type RPCDs in regional power grids with a high proportion of WP.The RPCDs are located according to the proposed static voltage stability index(VSI)and dynamicVSI based on dynamic voltage drop area,and the optimal configuration model of RPCDs is constructed with the lowest construction cost as the objective function to determine the installed capacity of various RPCDs.Finally,the corresponding regional power grid model for intensive access to WFs is constructed on the simulation platform to verify the effectiveness of the proposed method.展开更多
In this paper, a strategy for the reactive power compensation and harmonic suppression of the power supply system in HT-7U superconductive Tokamak is proposed. The optimized approach is given in the parameters design...In this paper, a strategy for the reactive power compensation and harmonic suppression of the power supply system in HT-7U superconductive Tokamak is proposed. The optimized approach is given in the parameters design for passive filter. Also a controlling method with fast response time and good accuracy is put forward for the compensator, which is more suitable for the dynamic load.展开更多
This paper introduces in detail the reactive power compensation technology and its characteristics, to reduce the loss of reactive power compensation technology 1N power distribution system and the electrical automati...This paper introduces in detail the reactive power compensation technology and its characteristics, to reduce the loss of reactive power compensation technology 1N power distribution system and the electrical automation, improve the utilization rate, and realize the control of the voltage amplitude in the system network, voltage stability of power distribution system, has carried on the system analysis to reduce failure of the harmonic current to the power supply system and other functions. And the paper in-depth study on the application of reactive power compensation technology in electrical automation from the reactive compensation technology, substation and distribution line reactive power compensation, power users of reactive power compensation and other aspects.展开更多
The source system covering a working frequency range of 24 MHz to 70 MHz with a total maximum output power of 12 MW has already been fabricated for Ion Cyclotron Range of Frequency（ICRF） heating in EAST from 2012. T...The source system covering a working frequency range of 24 MHz to 70 MHz with a total maximum output power of 12 MW has already been fabricated for Ion Cyclotron Range of Frequency（ICRF） heating in EAST from 2012. There are two continuous wave（CW） antennas consisting of four launching elements each fed by a separate 1.5 MW transmitter. Due to the strong mutual coupling among the launching elements, the injection power for launching elements should be imbalance to keep the k｜｜（parallel wave number） spectrum of the launcher symmetric for ICRF heating. Cross power induced by the mutual coupling will also induce many significant issues,such as an uncontrollable phase of currents in launching elements, high voltage standing wave ratio（VSWR）, and impedance mismatching. It is necessary to develop a power compensation system for antennas to keep the power balance between the feed points. The power balance system consists of two significant parts： a decoupler and phase control. The decoupler helps to achieve ports isolation to make the differential phase controllable and compensate partly cross power. After that, the differential phase of 0 or π will keep the power balance of two feed points completely. The first power compensation system consisting of four decouplers was assembled and tested for the port B antenna at the working frequency of 35 MHz. With the application of the power compensation system, the power balance, phase feedback control, and voltage standing wave ratio（VSWR） had obviously been improved in the 2015 EAST campaign.展开更多
Inevitably, the question of reactive power compensation was aroused by applied of power electronics. Based on the study of the instantaneous reactive power theory, the designs of TCR(thyristor control reactor) thyrist...Inevitably, the question of reactive power compensation was aroused by applied of power electronics. Based on the study of the instantaneous reactive power theory, the designs of TCR(thyristor control reactor) thyristor control reactor reac- tive power compensation system and TCR single closed loop strategy was pro- posed. In addition, as digital simulation software, Arene was applied to simulate the Jining coal mine No.2 system. The simulation results validate that the design is effective to improve power factor and stabilization of the system.展开更多
The article states about reactive power compensation methods for circuits with non-sinusoidal voltages. An basic introduction to reactive power theory has been given, together with the optimal capacitance selection th...The article states about reactive power compensation methods for circuits with non-sinusoidal voltages. An basic introduction to reactive power theory has been given, together with the optimal capacitance selection theory. There have been presented selected theories application in order to compensate the reactive power in one-phase circuits. The measurement results before the compensation have been discussed and measurement results after compensation of an actual object supplied from an non-sinusoidal voltage source were presented. The algorithms of optimal capacity selection were given, which connected in parallel to the circuit with inductive character will cause current root-mean-square value minimization. The measurement results after applying the reactive power minimization algorithm have shown improvement in compensation of strongly nonlinear receivers supplied with distorted signals.展开更多
Under the development trend of electrical automation, the application of reactive power compensation technology can give full play to the technical advantages, ensure the normal operation of the whole system, reduce p...Under the development trend of electrical automation, the application of reactive power compensation technology can give full play to the technical advantages, ensure the normal operation of the whole system, reduce power loss, reduce economic cost, and better realize the operation and high-quality development of electrical automation.展开更多
In the 21st century, with the rapid development of national economy, the task of national power industry is more difficult, along with the development of economy, China's power industry is also keeping pace with T...In the 21st century, with the rapid development of national economy, the task of national power industry is more difficult, along with the development of economy, China's power industry is also keeping pace with The Times. Due to the rapid development of industry and the increasing demand for power, with the increasing energy consumption year by year, the reactive loss in modern power grid also increases sharply, which deteriorates the power quality of the power grid, and also increases the burden and loss of lines and transformers. Now the country is advocating energy conservation and emission reduction, so the problem of reactive power compensation in the power grid has attracted more and more attention from scholars. Whether in industrial load or living load, resistance load accounts for a large proportion, such as transformers, asynchronous motors and many home appliances are resistant and perceptual load. The power factor of these loads is relatively small, and the reactive power they consume occupies a high share of the power transmission system .If the reactive power in the line can be reduced, the power transmission efficiency can be improved.展开更多
Many industrial installations in developing countries start-up as small factories, without regard for the need of compensation of reactive power, leading to significant financial losses in the long term. By improving ...Many industrial installations in developing countries start-up as small factories, without regard for the need of compensation of reactive power, leading to significant financial losses in the long term. By improving the power factor, the customer can reduce its power demand and potentially increase efficiency of their equipment. A PIC microcontroller is used to switch capacitor banks to compensate for the reactive power. In order to determine the size of the capacitor bank needed, the microcontroller calculates the phase difference between the voltage and the current. The results obtained based on the lagging power factor for three test loads show an improvement in the power factor from 0.52 to 0.96 under different test load conditions.展开更多
This paper proposes an autonomous finite-time disturbance observer-based control(FTDOBC)scheme to simultaneously achieve speed/frequency regulation and dynamic power compensation.The proposed approach is designed for ...This paper proposes an autonomous finite-time disturbance observer-based control(FTDOBC)scheme to simultaneously achieve speed/frequency regulation and dynamic power compensation.The proposed approach is designed for a standalone micro turbine generation system operating under aerospace power demands.Unlike centralized architectures relying on real-time communication between subsystems,the proposed method embeds finite-time disturbance observers(FTDOs)into each dynamic stage of the micro turbine(MT)model.It enables independent estimation and compensation of mismatched/matched disturbances(e.g.,load power fluctuations,system uncertainties).Then,the composite controller is finally designed by the estimates of local FTDOs and the state feedback control law.Theoretical analysis proves that the FTDOBC method guarantees the finite-time convergence of dynamic power estimation and the asymptotically convergence of speed tracking errors.Simulations demonstrate that the proposed method can maintain the speed/frequency at the reference value rapidly,even under the demand of ramped and step load power.It also reveals that the demand power load is compensated rapidly by the proposed method.By capacitating a single MT to autonomously balance frequency stability and dynamic power demand,this work provides a foundational control paradigm for future distributed aviation energy systems.展开更多
The complex working environment of distribution networks tends to cause impermanent single-phase-to-ground(SPG)fault,and high-temperature ground fault arc is prone to endanger lives and power equipment,resulting in la...The complex working environment of distribution networks tends to cause impermanent single-phase-to-ground(SPG)fault,and high-temperature ground fault arc is prone to endanger lives and power equipment,resulting in large-scale power outages and fire accidents.Thus,fault arc should be extinguished in time.Meanwhile,stable operation conditions of distribution networks and reliable load power supply should be guaranteed to provide high-quality customer service.This paper proposes an active mitigation strategy for SPG fault,and provide active and reactive power compensation at the same time by utilizing an improved flexible power electronic equipment(FPEE)with dc-link sources.These controls are decoupled from each other,so utilization of FPEE is maximized as much as possible.When a SPG fault occurs in distribution networks,FPEE can output,simultaneously,active power,reactive power,and SPG fault compensation current by controlling output current on the d,q,0 coordinate system,respectively.During normal operation of distribution networks,the FPEE can be used as a virtual synchronous generator to compensate load power and its fluctuation.The proposed simultaneous multi-function can also be applied in other cases.Simulation cases are implemented to verify principles and practicability.展开更多
The purpose of this study is to solve the main problems in distribution networks,including increased line loss and reduced power supply quality caused by insufficient capacitive reactive power.To reduce the capacity,v...The purpose of this study is to solve the main problems in distribution networks,including increased line loss and reduced power supply quality caused by insufficient capacitive reactive power.To reduce the capacity,voltage,and current stress of an active module of a compensation device and improve the cost performance of the device,an improved hybrid reactive power compensation system based on a fixed capacitor(FC)and a static synchronous compensator(STATCOM)is proposed.The topological structure and basic operating principle of the proposed reactive power compensation system are introduced.In addition,from the perspectives of output voltage,current,power,loss of the active part,and system compensation cost,the performances of the proposed reactive compensator and the inductively coupled STATCOM(L-STATCOM)are compared and analyzed.Furthermore,the key parameters of the proposed system are designed,and the joint optimization control strategy of the FC and STATCOM is studied.The correctness and effectiveness of the proposed topology structure and control method are verified by simulations.展开更多
The paper introduces one design idea that making use of SCM to control Real-timely the dynamic compensation of reactive power.Firstly,design one Circuit to Sample the voltage and current,and by these datas we can easi...The paper introduces one design idea that making use of SCM to control Real-timely the dynamic compensation of reactive power.Firstly,design one Circuit to Sample the voltage and current,and by these datas we can easily calculate the power factor,and Voltage controller in the microcontroller to determine whether input the compensation capacitance according to the size of power factor,the paper also analyzes the principle of capacitance compensation and calculation method. Dynamic compensation for the entire process is quick and accurate.展开更多
The dynamic reactive power compensation equipment in Jiuquan Wind Power Base of above 10 GW consists of three different types of compensation devices, including： static var generator （SVG）, thyristor controlled com...The dynamic reactive power compensation equipment in Jiuquan Wind Power Base of above 10 GW consists of three different types of compensation devices, including： static var generator （SVG）, thyristor controlled compensator （TGR） and magnetically controlled reactor （MGR）. The lack of experimental verification of performance is not conducive to voltage/var management or full utilization of device capaci- ties. In order to solve the above problems, the compensation device performance test was performed. The test items and procedures were selected based on related national standards with the consideration for different grid structures and wind farm operation modes. The testing contents included dynamic regulating range, active power loss, dynamic response time, and harmonic voltage level. Three types of compensation devices installed in different wind farms, namely SVG, TCR and MCR, were chosen and tested. The performances were compared and analyzed according to the field test results.展开更多
With the parallel development of power supply system and compensation technology, reactive power compensation technology is increasingly widely used. The application of reactive power compensation technology in subway...With the parallel development of power supply system and compensation technology, reactive power compensation technology is increasingly widely used. The application of reactive power compensation technology in subway power supply system can solve the problems of harmonic, voltage fluctuation and low power factors. It can make the power factor of the power supply system conform to the power grid operation specifications, reduce the voltage fluctuation, harmonic and other problems, and have the impact on the subway power system. According to the actual operation of the power supply system in the subway, the power factor can be improved by properly controlling the reactive power compensation strategy to ensure the stable operation of the power supply system in the subway.展开更多
In order to improve the Power Quality(PQ)of traction power supply system and reduce the power rating and operation cost of compensator,a Static VAR Compensator(SVC)integrated Railway Power Conditioner(RPC)is presented...In order to improve the Power Quality(PQ)of traction power supply system and reduce the power rating and operation cost of compensator,a Static VAR Compensator(SVC)integrated Railway Power Conditioner(RPC)is presented in this paper.RPC is a widely used device in the AC electrified railway systems to enhance the PQ indices of the main network.The next generation of this equipment is Active Power Quality Compensator(APQC).The major concern of these compensators is their high kVA rating.In this paper,a hybrid technique is proposed to solve aforementioned problems.A combination of SVC as an auxiliary device is employed together with the main compensators,i.e.,RPC and APQC that leads on to the reduction of power rating of the main compensators.The use of proposed scheme will cause to reduce significantly the initial investment cost of compensation system.The main compensators are only utilized to balance active powers of two adjacent feeder sections and suppress harmonic currents.The SVCs are used to compensate reactive power and suppress the third and fifth harmonic currents.In this paper firstly,the PQ compensation procedure in AC electrified railway is analyzed step by step.Then,the control strategies for SVC and the main compensators are presented.Finally,a simulation is fulfilled using Matlab/Simulink software to verify the effectiveness and validity of the proposed scheme and compensation strategy and also demonstrate that this technique could compensate all PQ problems.展开更多
Since the lower power requirement of code division multiple access(CDMA) than that of other multiple access, the CDMA technology is suitable to be used in low earth orbit(LEO) satellite communication system whose spac...Since the lower power requirement of code division multiple access(CDMA) than that of other multiple access, the CDMA technology is suitable to be used in low earth orbit(LEO) satellite communication system whose space power is limited due to the small size of satellite. The pilot channel of CDMA technology is very important for earth mobile station(EMS) in LEO system to recover carrier and code, but the power requirement of pilot channel is very higher than that of other channels. In this paper, a power reduction method for pilot channel is proposed. By the new method, the power of pilot channel transmitted from LEO satellite is reduced to a lower level. For improving the signal to noise ratio(SNR) of pilot channel with lower power, coherent integration is employed in EMS at the pre-processing stage. Considering the high dynamic situation of LEO satellite, the long period of time for integration will deteriorate the receiving performance of EMS, therefore, a dynamic compensation module is added to carrier tracking loop against the high dynamic. Meanwhile, the transfer function of the new tracking loop and the condition for steadystate zero error are deduced. Numerical examples are provided to demonstrate effectiveness of the proposed approach.展开更多
This article investigates the power quality enhancement in power system using one of the most famous series converter based FACTS controller like IPFC (Interline Power Flow Controller) in Power Injection Model (PIM). ...This article investigates the power quality enhancement in power system using one of the most famous series converter based FACTS controller like IPFC (Interline Power Flow Controller) in Power Injection Model (PIM). The parameters of PIM are derived with help of the Newton-Raphson power flow algorithm. In general, a sample test power system without FACTs devices has generated more reactive power, decreased real power, more harmonics, small power factor and poor dynamic performance under line and load variations. In order to improve the real power, compensating the reactive power, proficient power factor and excellent load voltage regulation in the sample test power system, an IPFC is designed. The D-Q technique is utilized here to derive the reference current of the converter and its D.C link capacitor voltage is regulated. Also, the reference voltage of the inverter is arrived by park transformation technique and its load voltage is controlled. Here, a sample 230 KV test power system is taken for study. Further as the conventional PI controllers are designed at one nominal operating point they are not competent to respond satisfactorily in dynamic operating conditions. This can be circumvented by a Fuzzy and Neural network based IPFC and its detailed Simulink model is developed using MATLAB and the overall performance analysis is carried out under different operating state of affairs.展开更多
Effective reactive power compensation is very important to the safe,economical and high quality running of power system.The principle and characteristic of several main reactive power compensation devices were analyze...Effective reactive power compensation is very important to the safe,economical and high quality running of power system.The principle and characteristic of several main reactive power compensation devices were analyzed and compared in details, and the development trend and application prospect were viewed.展开更多
基金supported by the key technology project of China Southern Power Grid Corporation(GZKJXM20220041)partly by theNational Key Research and Development Plan(2022YFE0205300).
文摘Aiming at the challenge of complex load balancing coordination for a three-phase four-leg(3P4L)based multi-ended low voltage flexible DC distribution system(M-LVDC)considering unbalanced power compensation,this paper proposes a phase-split power decoupling unbalanced compensation strategy based load balancing strategy for 3P4L based M-LVDC.Firstly,the topology and operation principle of the 3P4L-based M-LVDC system is introduced,and quasi-proportional resonant(QPR)based phase-split power current control for the 3P4L converter is proposed.Secondly,a load-balancing control strategy considering unbalanced compensation for 3P4L-based MLVDC is presented,in which the control diagrams for each 3P4L-based converter are detailed.The core idea of the proposed strategy is to comprehensively consider the imbalance compensation and load rate balancing between the two areas to calculate the split-phase power and current reference values of each 3P4L converter and achieve the static error-free tracking of the reference values through the QPR current inner-loop control.These reference values are then tracked with zero steady-state error using QPR current inner-loop control.Finally,the effectiveness of the proposed control strategy is verified through a 3P4L M-LVDC case study conducted on the PSCAD/EMTDC software.Theresults indicate that the proposed method not only can reduce the three-phase imbalance degrees from>20% to<0.5%,but also achieve excellent balanced load rates,with the load-rate difference smaller than 1.5%.
基金supported by the Science and Technology Project of State Grid Corporation Headquarters(No.5100-202323008A-1-1-ZN).
文摘As the large-scale development of wind farms(WFs)progresses,the connection ofWFs to the regional power grid is evolving from the conventional receiving power grid to the sending power grid with a high proportion of wind power(WP).Due to the randomness of WP output,higher requirements are put forward for the voltage stability of each node of the regional power grid,and various reactive power compensation devices(RPCDs)need to be rationally configured to meet the stable operation requirements of the system.This paper proposes an optimal configuration method for multi-type RPCDs in regional power grids with a high proportion of WP.The RPCDs are located according to the proposed static voltage stability index(VSI)and dynamicVSI based on dynamic voltage drop area,and the optimal configuration model of RPCDs is constructed with the lowest construction cost as the objective function to determine the installed capacity of various RPCDs.Finally,the corresponding regional power grid model for intensive access to WFs is constructed on the simulation platform to verify the effectiveness of the proposed method.
文摘In this paper, a strategy for the reactive power compensation and harmonic suppression of the power supply system in HT-7U superconductive Tokamak is proposed. The optimized approach is given in the parameters design for passive filter. Also a controlling method with fast response time and good accuracy is put forward for the compensator, which is more suitable for the dynamic load.
文摘This paper introduces in detail the reactive power compensation technology and its characteristics, to reduce the loss of reactive power compensation technology 1N power distribution system and the electrical automation, improve the utilization rate, and realize the control of the voltage amplitude in the system network, voltage stability of power distribution system, has carried on the system analysis to reduce failure of the harmonic current to the power supply system and other functions. And the paper in-depth study on the application of reactive power compensation technology in electrical automation from the reactive compensation technology, substation and distribution line reactive power compensation, power users of reactive power compensation and other aspects.
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2015GB101001)National Natural Science Foundation of China(Nos.11575237,11375235,11375236)
文摘The source system covering a working frequency range of 24 MHz to 70 MHz with a total maximum output power of 12 MW has already been fabricated for Ion Cyclotron Range of Frequency（ICRF） heating in EAST from 2012. There are two continuous wave（CW） antennas consisting of four launching elements each fed by a separate 1.5 MW transmitter. Due to the strong mutual coupling among the launching elements, the injection power for launching elements should be imbalance to keep the k｜｜（parallel wave number） spectrum of the launcher symmetric for ICRF heating. Cross power induced by the mutual coupling will also induce many significant issues,such as an uncontrollable phase of currents in launching elements, high voltage standing wave ratio（VSWR）, and impedance mismatching. It is necessary to develop a power compensation system for antennas to keep the power balance between the feed points. The power balance system consists of two significant parts： a decoupler and phase control. The decoupler helps to achieve ports isolation to make the differential phase controllable and compensate partly cross power. After that, the differential phase of 0 or π will keep the power balance of two feed points completely. The first power compensation system consisting of four decouplers was assembled and tested for the port B antenna at the working frequency of 35 MHz. With the application of the power compensation system, the power balance, phase feedback control, and voltage standing wave ratio（VSWR） had obviously been improved in the 2015 EAST campaign.
文摘Inevitably, the question of reactive power compensation was aroused by applied of power electronics. Based on the study of the instantaneous reactive power theory, the designs of TCR(thyristor control reactor) thyristor control reactor reac- tive power compensation system and TCR single closed loop strategy was pro- posed. In addition, as digital simulation software, Arene was applied to simulate the Jining coal mine No.2 system. The simulation results validate that the design is effective to improve power factor and stabilization of the system.
文摘The article states about reactive power compensation methods for circuits with non-sinusoidal voltages. An basic introduction to reactive power theory has been given, together with the optimal capacitance selection theory. There have been presented selected theories application in order to compensate the reactive power in one-phase circuits. The measurement results before the compensation have been discussed and measurement results after compensation of an actual object supplied from an non-sinusoidal voltage source were presented. The algorithms of optimal capacity selection were given, which connected in parallel to the circuit with inductive character will cause current root-mean-square value minimization. The measurement results after applying the reactive power minimization algorithm have shown improvement in compensation of strongly nonlinear receivers supplied with distorted signals.
文摘Under the development trend of electrical automation, the application of reactive power compensation technology can give full play to the technical advantages, ensure the normal operation of the whole system, reduce power loss, reduce economic cost, and better realize the operation and high-quality development of electrical automation.
文摘In the 21st century, with the rapid development of national economy, the task of national power industry is more difficult, along with the development of economy, China's power industry is also keeping pace with The Times. Due to the rapid development of industry and the increasing demand for power, with the increasing energy consumption year by year, the reactive loss in modern power grid also increases sharply, which deteriorates the power quality of the power grid, and also increases the burden and loss of lines and transformers. Now the country is advocating energy conservation and emission reduction, so the problem of reactive power compensation in the power grid has attracted more and more attention from scholars. Whether in industrial load or living load, resistance load accounts for a large proportion, such as transformers, asynchronous motors and many home appliances are resistant and perceptual load. The power factor of these loads is relatively small, and the reactive power they consume occupies a high share of the power transmission system .If the reactive power in the line can be reduced, the power transmission efficiency can be improved.
文摘Many industrial installations in developing countries start-up as small factories, without regard for the need of compensation of reactive power, leading to significant financial losses in the long term. By improving the power factor, the customer can reduce its power demand and potentially increase efficiency of their equipment. A PIC microcontroller is used to switch capacitor banks to compensate for the reactive power. In order to determine the size of the capacitor bank needed, the microcontroller calculates the phase difference between the voltage and the current. The results obtained based on the lagging power factor for three test loads show an improvement in the power factor from 0.52 to 0.96 under different test load conditions.
文摘This paper proposes an autonomous finite-time disturbance observer-based control(FTDOBC)scheme to simultaneously achieve speed/frequency regulation and dynamic power compensation.The proposed approach is designed for a standalone micro turbine generation system operating under aerospace power demands.Unlike centralized architectures relying on real-time communication between subsystems,the proposed method embeds finite-time disturbance observers(FTDOs)into each dynamic stage of the micro turbine(MT)model.It enables independent estimation and compensation of mismatched/matched disturbances(e.g.,load power fluctuations,system uncertainties).Then,the composite controller is finally designed by the estimates of local FTDOs and the state feedback control law.Theoretical analysis proves that the FTDOBC method guarantees the finite-time convergence of dynamic power estimation and the asymptotically convergence of speed tracking errors.Simulations demonstrate that the proposed method can maintain the speed/frequency at the reference value rapidly,even under the demand of ramped and step load power.It also reveals that the demand power load is compensated rapidly by the proposed method.By capacitating a single MT to autonomously balance frequency stability and dynamic power demand,this work provides a foundational control paradigm for future distributed aviation energy systems.
基金supported in part by the National Natural Science Foundation of China(No.51677030).
文摘The complex working environment of distribution networks tends to cause impermanent single-phase-to-ground(SPG)fault,and high-temperature ground fault arc is prone to endanger lives and power equipment,resulting in large-scale power outages and fire accidents.Thus,fault arc should be extinguished in time.Meanwhile,stable operation conditions of distribution networks and reliable load power supply should be guaranteed to provide high-quality customer service.This paper proposes an active mitigation strategy for SPG fault,and provide active and reactive power compensation at the same time by utilizing an improved flexible power electronic equipment(FPEE)with dc-link sources.These controls are decoupled from each other,so utilization of FPEE is maximized as much as possible.When a SPG fault occurs in distribution networks,FPEE can output,simultaneously,active power,reactive power,and SPG fault compensation current by controlling output current on the d,q,0 coordinate system,respectively.During normal operation of distribution networks,the FPEE can be used as a virtual synchronous generator to compensate load power and its fluctuation.The proposed simultaneous multi-function can also be applied in other cases.Simulation cases are implemented to verify principles and practicability.
基金Supported by the General Project of Hunan Natural Science Foundation(2021JJ30715)the Scientific Research Fund of Hunan Provincial Education Department(20B029)the Graduate Research Innovation Project of Changsha University of Science&Technology(CX2021SS52).
文摘The purpose of this study is to solve the main problems in distribution networks,including increased line loss and reduced power supply quality caused by insufficient capacitive reactive power.To reduce the capacity,voltage,and current stress of an active module of a compensation device and improve the cost performance of the device,an improved hybrid reactive power compensation system based on a fixed capacitor(FC)and a static synchronous compensator(STATCOM)is proposed.The topological structure and basic operating principle of the proposed reactive power compensation system are introduced.In addition,from the perspectives of output voltage,current,power,loss of the active part,and system compensation cost,the performances of the proposed reactive compensator and the inductively coupled STATCOM(L-STATCOM)are compared and analyzed.Furthermore,the key parameters of the proposed system are designed,and the joint optimization control strategy of the FC and STATCOM is studied.The correctness and effectiveness of the proposed topology structure and control method are verified by simulations.
文摘The paper introduces one design idea that making use of SCM to control Real-timely the dynamic compensation of reactive power.Firstly,design one Circuit to Sample the voltage and current,and by these datas we can easily calculate the power factor,and Voltage controller in the microcontroller to determine whether input the compensation capacitance according to the size of power factor,the paper also analyzes the principle of capacitance compensation and calculation method. Dynamic compensation for the entire process is quick and accurate.
文摘The dynamic reactive power compensation equipment in Jiuquan Wind Power Base of above 10 GW consists of three different types of compensation devices, including： static var generator （SVG）, thyristor controlled compensator （TGR） and magnetically controlled reactor （MGR）. The lack of experimental verification of performance is not conducive to voltage/var management or full utilization of device capaci- ties. In order to solve the above problems, the compensation device performance test was performed. The test items and procedures were selected based on related national standards with the consideration for different grid structures and wind farm operation modes. The testing contents included dynamic regulating range, active power loss, dynamic response time, and harmonic voltage level. Three types of compensation devices installed in different wind farms, namely SVG, TCR and MCR, were chosen and tested. The performances were compared and analyzed according to the field test results.
文摘With the parallel development of power supply system and compensation technology, reactive power compensation technology is increasingly widely used. The application of reactive power compensation technology in subway power supply system can solve the problems of harmonic, voltage fluctuation and low power factors. It can make the power factor of the power supply system conform to the power grid operation specifications, reduce the voltage fluctuation, harmonic and other problems, and have the impact on the subway power system. According to the actual operation of the power supply system in the subway, the power factor can be improved by properly controlling the reactive power compensation strategy to ensure the stable operation of the power supply system in the subway.
文摘In order to improve the Power Quality(PQ)of traction power supply system and reduce the power rating and operation cost of compensator,a Static VAR Compensator(SVC)integrated Railway Power Conditioner(RPC)is presented in this paper.RPC is a widely used device in the AC electrified railway systems to enhance the PQ indices of the main network.The next generation of this equipment is Active Power Quality Compensator(APQC).The major concern of these compensators is their high kVA rating.In this paper,a hybrid technique is proposed to solve aforementioned problems.A combination of SVC as an auxiliary device is employed together with the main compensators,i.e.,RPC and APQC that leads on to the reduction of power rating of the main compensators.The use of proposed scheme will cause to reduce significantly the initial investment cost of compensation system.The main compensators are only utilized to balance active powers of two adjacent feeder sections and suppress harmonic currents.The SVCs are used to compensate reactive power and suppress the third and fifth harmonic currents.In this paper firstly,the PQ compensation procedure in AC electrified railway is analyzed step by step.Then,the control strategies for SVC and the main compensators are presented.Finally,a simulation is fulfilled using Matlab/Simulink software to verify the effectiveness and validity of the proposed scheme and compensation strategy and also demonstrate that this technique could compensate all PQ problems.
基金supported by the National High Technology Research and Development Program of China (863 Program) (No.2012AA01A502)the National Natural Science Foundation of China (No.61179006)the Science and Technology Support Program of Sichuan Province (No.2014GZX0004)
文摘Since the lower power requirement of code division multiple access(CDMA) than that of other multiple access, the CDMA technology is suitable to be used in low earth orbit(LEO) satellite communication system whose space power is limited due to the small size of satellite. The pilot channel of CDMA technology is very important for earth mobile station(EMS) in LEO system to recover carrier and code, but the power requirement of pilot channel is very higher than that of other channels. In this paper, a power reduction method for pilot channel is proposed. By the new method, the power of pilot channel transmitted from LEO satellite is reduced to a lower level. For improving the signal to noise ratio(SNR) of pilot channel with lower power, coherent integration is employed in EMS at the pre-processing stage. Considering the high dynamic situation of LEO satellite, the long period of time for integration will deteriorate the receiving performance of EMS, therefore, a dynamic compensation module is added to carrier tracking loop against the high dynamic. Meanwhile, the transfer function of the new tracking loop and the condition for steadystate zero error are deduced. Numerical examples are provided to demonstrate effectiveness of the proposed approach.
文摘This article investigates the power quality enhancement in power system using one of the most famous series converter based FACTS controller like IPFC (Interline Power Flow Controller) in Power Injection Model (PIM). The parameters of PIM are derived with help of the Newton-Raphson power flow algorithm. In general, a sample test power system without FACTs devices has generated more reactive power, decreased real power, more harmonics, small power factor and poor dynamic performance under line and load variations. In order to improve the real power, compensating the reactive power, proficient power factor and excellent load voltage regulation in the sample test power system, an IPFC is designed. The D-Q technique is utilized here to derive the reference current of the converter and its D.C link capacitor voltage is regulated. Also, the reference voltage of the inverter is arrived by park transformation technique and its load voltage is controlled. Here, a sample 230 KV test power system is taken for study. Further as the conventional PI controllers are designed at one nominal operating point they are not competent to respond satisfactorily in dynamic operating conditions. This can be circumvented by a Fuzzy and Neural network based IPFC and its detailed Simulink model is developed using MATLAB and the overall performance analysis is carried out under different operating state of affairs.
文摘Effective reactive power compensation is very important to the safe,economical and high quality running of power system.The principle and characteristic of several main reactive power compensation devices were analyzed and compared in details, and the development trend and application prospect were viewed.
