Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the...Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the second generator by errors in the rotor rotating speed calculation are found,and the tuning method of the speed related parameters are given.The damping and reverse tuning characteristics of power system stabilizers(PSSs)in the digital automatic voltage regulator(AVR)are compared and investigated in the frequency range of 0.18-1.1 Hz.The efficiency of the proposed tuning method for ensuring power system stability is verified by RTDS.Finally,field tests show the validity of the laboratory test results.展开更多
The main objective of this paper is to develop PI and fuzzy controllers to analyze the performance of instantaneous real active and reactive power （p-q） control strategy for extracting reference currents of shunt ac...The main objective of this paper is to develop PI and fuzzy controllers to analyze the performance of instantaneous real active and reactive power （p-q） control strategy for extracting reference currents of shunt active filters （SHAFs） under balanced, unbalanced, and balanced non-sinusoidal conditions. When the supply voltages are balanced and sinusoidal, both controllers converge to the same compensation characteristics. However, if the supply voltages are distorted and/or unbalanced sinusoidal, these controllers result in different degrees of compensation in harmonics. The p-q control strategy with PI controller is unable to yield an adequate solution when source voltages are not ideal. Extensive simulations were carried out with balance, unbalanced, and non-sinusoidal conditions. Simulation results validate the superiority of fuzzy logic controller over PI controller. The three-phase four-wire SHAF system is also implemented on a real-time digital simulator （RTDS hardware） to further verify its effective-ness. The detailed simulation and RTDS hardware results are included.展开更多
The development of low-carbon energy systems and renewable energy sources(RESs)are critical to solving the energy crisis around the world.However,renewable energy gen eration control strategies lead to fault character...The development of low-carbon energy systems and renewable energy sources(RESs)are critical to solving the energy crisis around the world.However,renewable energy gen eration control strategies lead to fault characteristics such as fault current amplitude limitation and phase angle distortion.Focusing on large-scale renewable energy transmission lines,the sensitivity of traditional current differential protection and distance protection may be reduced,and there is even the risk of maloperation.Therefore,a suitable transmission line model is established,which considers the distributed capacitance.Af terward,a novel dynamic state estimation based protection(DSEBP)for large-scale renewable energy transmission lines is proposed.The proposed DSEBP adopts instantaneous measure ments and additional protection criteria to ensure the quick ac tion and reliability.Finally,faults are identified by checking the matching degree between the actual measurements and the es tablished transmission line model.The performance of the pro posed DSEBP is verified through PSCAD/EMTDC and realtime digital simulator(RTDS)hardware-in-loop tests.The re sults demonstrate that the proposed DSEBP can identify vari ous types of faults quickly and reliably.Meanwhile,the pro posed DSEBP has a better capability to withstand fault resis tance and disturbance.展开更多
The increasing penetration of inverter-based distributed generations(DGs)significantly affects the fault characteristics of distribution networks.Fault analysis is a keystone for suitable protection scheme design.This...The increasing penetration of inverter-based distributed generations(DGs)significantly affects the fault characteristics of distribution networks.Fault analysis is a keystone for suitable protection scheme design.This paper presents the modelling methodology for distribution networks with inverter-based DGs and performs fault simulation based on the model.Firstly,a single inverter-based DG model based on the cascaded control structure is developed.Secondly,a simulation model of distribution network with two inverter-based DGs is established.Then,different fault simulations are performed based on the Real Time Digital Simulator(RTDS).Theoretical analyses are conducted to justify the simulation results,including the equivalent circuit of distribution networks with inverter-based DGs and the solution method for loop currents.展开更多
文摘Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the second generator by errors in the rotor rotating speed calculation are found,and the tuning method of the speed related parameters are given.The damping and reverse tuning characteristics of power system stabilizers(PSSs)in the digital automatic voltage regulator(AVR)are compared and investigated in the frequency range of 0.18-1.1 Hz.The efficiency of the proposed tuning method for ensuring power system stability is verified by RTDS.Finally,field tests show the validity of the laboratory test results.
文摘The main objective of this paper is to develop PI and fuzzy controllers to analyze the performance of instantaneous real active and reactive power （p-q） control strategy for extracting reference currents of shunt active filters （SHAFs） under balanced, unbalanced, and balanced non-sinusoidal conditions. When the supply voltages are balanced and sinusoidal, both controllers converge to the same compensation characteristics. However, if the supply voltages are distorted and/or unbalanced sinusoidal, these controllers result in different degrees of compensation in harmonics. The p-q control strategy with PI controller is unable to yield an adequate solution when source voltages are not ideal. Extensive simulations were carried out with balance, unbalanced, and non-sinusoidal conditions. Simulation results validate the superiority of fuzzy logic controller over PI controller. The three-phase four-wire SHAF system is also implemented on a real-time digital simulator （RTDS hardware） to further verify its effective-ness. The detailed simulation and RTDS hardware results are included.
基金supported by National Natural Science Foundation of ChinaState Grid Corporation Joint Fund for Smart Grid(No.U2066210).
文摘The development of low-carbon energy systems and renewable energy sources(RESs)are critical to solving the energy crisis around the world.However,renewable energy gen eration control strategies lead to fault characteristics such as fault current amplitude limitation and phase angle distortion.Focusing on large-scale renewable energy transmission lines,the sensitivity of traditional current differential protection and distance protection may be reduced,and there is even the risk of maloperation.Therefore,a suitable transmission line model is established,which considers the distributed capacitance.Af terward,a novel dynamic state estimation based protection(DSEBP)for large-scale renewable energy transmission lines is proposed.The proposed DSEBP adopts instantaneous measure ments and additional protection criteria to ensure the quick ac tion and reliability.Finally,faults are identified by checking the matching degree between the actual measurements and the es tablished transmission line model.The performance of the pro posed DSEBP is verified through PSCAD/EMTDC and realtime digital simulator(RTDS)hardware-in-loop tests.The re sults demonstrate that the proposed DSEBP can identify vari ous types of faults quickly and reliably.Meanwhile,the pro posed DSEBP has a better capability to withstand fault resis tance and disturbance.
基金Nation Natural Science Foundation of China(51377100)the Key Scientific and Technological Project of State Grid Shandong Power Company(SGSDWF00YJJS1400563).
文摘The increasing penetration of inverter-based distributed generations(DGs)significantly affects the fault characteristics of distribution networks.Fault analysis is a keystone for suitable protection scheme design.This paper presents the modelling methodology for distribution networks with inverter-based DGs and performs fault simulation based on the model.Firstly,a single inverter-based DG model based on the cascaded control structure is developed.Secondly,a simulation model of distribution network with two inverter-based DGs is established.Then,different fault simulations are performed based on the Real Time Digital Simulator(RTDS).Theoretical analyses are conducted to justify the simulation results,including the equivalent circuit of distribution networks with inverter-based DGs and the solution method for loop currents.
