提出了一种能模拟电力系统电压扰动与电流扰动输出的电能质量扰动综合发生装置,能输出电压暂降、电压波动和闪变、电压谐波、电流谐波、电压电流三相不平衡等波形,具有输出波形好、功率大、电压等级较高等特点。该装置采用多绕组变压器...提出了一种能模拟电力系统电压扰动与电流扰动输出的电能质量扰动综合发生装置,能输出电压暂降、电压波动和闪变、电压谐波、电流谐波、电压电流三相不平衡等波形,具有输出波形好、功率大、电压等级较高等特点。该装置采用多绕组变压器+全控型变流器+载波移相级联型多电平变流器结构,整流部分采用电压电流双环控制,输入电流波形好,直压稳定,逆变侧采用载波移相级联多电平控制策略,输出波形精度高。在PSCAD仿真分析的基础上,研制1.5 MVA/10 k V电能质量扰动综合发生装置样机,仿真和实验结果验证了装置主电路和控制策略的正确性。展开更多
This letter studies large-disturbance stability of the power system with a synchronous generator(SG)and a converter-interfaced generation(CIG)connected to infinite bus.The power system is multi-timescale and first sim...This letter studies large-disturbance stability of the power system with a synchronous generator(SG)and a converter-interfaced generation(CIG)connected to infinite bus.The power system is multi-timescale and first simplified.It is shown that the boundary of region of attraction(ROA)of the simplified model is composed of stable manifolds of unstable equilibrium point(UEP)or semi-singular point(SSP),named anchor points,and singular surface pieces.The type of anchor point determines the dominant instability pattern of the power system.When the anchor point is UEP or SSP,the dominant instability pattern is the instability of rotor angle of SG or the instability of phase-locked loop and outer control loop(OCL)of CIG,respectively.Transition of dominant instability pattern can be analyzed with the relative position relationship between UEP and SSP.The effect of OCL is discussed.When the OCL is activated,the ROA becomes smaller and the system is more prone to instability of CIG.It is necessary to consider the OCL when studying the large-disturbance stability of the power system.展开更多
Disconnections due to voltage drops in the grid cannot be permitted if wind turbines(WTs)contribute significantly to electricity pro-duction,as this increases the risk of production loss and destabilizes the grid.To m...Disconnections due to voltage drops in the grid cannot be permitted if wind turbines(WTs)contribute significantly to electricity pro-duction,as this increases the risk of production loss and destabilizes the grid.To mitigate the negative effects of these occurrences,WTs must be able to ride through the low-voltage conditions and inject reactive current to provide dynamic voltage support.This paper investigates the low-voltage ride-through(LVRT)capability enhancement of a Type-3 WT utilizing a dynamic voltage restorer(DVR).During the grid voltage drop,the DVR quickly injects a compensating voltage to keep the stator voltage constant.This paper proposes an active disturbance rejection control(ADRC)scheme to control the rotor-side,grid-side and DVR-side converters in a wind–DVR integrated network.The performance of the Type-3 WT with DVR topology is evaluated under various test conditions using MATLAB®/Simulink®.These simulation results are also compared with the experimental results for the LVRT capability performed on a WT emulator equipped with a crowbar and direct current(DC)chopper.The simulation results demonstrate a favourable transient and steady-state response of the Type-3 wind turbine quantities defined by the LVRT codes,as well as improved reactive power support under balanced fault conditions.Under the most severe voltage drop of 95%,the stator currents,rotor currents and DC bus voltage are 1.25 pu,1.40 pu and 1.09 UDC,respectively,conforming to the values of the LVRT codes.DVR controlled by the ADRC technique significantly increases the LVRT capabilities of a Type-3 doubly-fed induction generator-based WT under symmetrical voltage dip events.Although setting up ADRC controllers might be challenging,the proposed method has been shown to be extremely effective in reducing all kinds of internal and external disturbances.展开更多
1.General ReviewThe rapid development of extra high voltage transmissionlines and power systems raised serious stability problems.Becauseof the long distance transmission of power and relative weak systemconfiguration...1.General ReviewThe rapid development of extra high voltage transmissionlines and power systems raised serious stability problems.Becauseof the long distance transmission of power and relative weak systemconfiguration,stability became the most important and seriousproblems.The risks in terms of disturbance causing subsequentsystem instability could be very high and the results of frequency andvoltage collapse may cause catastrophic results.展开更多
文摘提出了一种能模拟电力系统电压扰动与电流扰动输出的电能质量扰动综合发生装置,能输出电压暂降、电压波动和闪变、电压谐波、电流谐波、电压电流三相不平衡等波形,具有输出波形好、功率大、电压等级较高等特点。该装置采用多绕组变压器+全控型变流器+载波移相级联型多电平变流器结构,整流部分采用电压电流双环控制,输入电流波形好,直压稳定,逆变侧采用载波移相级联多电平控制策略,输出波形精度高。在PSCAD仿真分析的基础上,研制1.5 MVA/10 k V电能质量扰动综合发生装置样机,仿真和实验结果验证了装置主电路和控制策略的正确性。
基金supported by the National Natural Science Foundation of China(No.U2066602)。
文摘This letter studies large-disturbance stability of the power system with a synchronous generator(SG)and a converter-interfaced generation(CIG)connected to infinite bus.The power system is multi-timescale and first simplified.It is shown that the boundary of region of attraction(ROA)of the simplified model is composed of stable manifolds of unstable equilibrium point(UEP)or semi-singular point(SSP),named anchor points,and singular surface pieces.The type of anchor point determines the dominant instability pattern of the power system.When the anchor point is UEP or SSP,the dominant instability pattern is the instability of rotor angle of SG or the instability of phase-locked loop and outer control loop(OCL)of CIG,respectively.Transition of dominant instability pattern can be analyzed with the relative position relationship between UEP and SSP.The effect of OCL is discussed.When the OCL is activated,the ROA becomes smaller and the system is more prone to instability of CIG.It is necessary to consider the OCL when studying the large-disturbance stability of the power system.
文摘Disconnections due to voltage drops in the grid cannot be permitted if wind turbines(WTs)contribute significantly to electricity pro-duction,as this increases the risk of production loss and destabilizes the grid.To mitigate the negative effects of these occurrences,WTs must be able to ride through the low-voltage conditions and inject reactive current to provide dynamic voltage support.This paper investigates the low-voltage ride-through(LVRT)capability enhancement of a Type-3 WT utilizing a dynamic voltage restorer(DVR).During the grid voltage drop,the DVR quickly injects a compensating voltage to keep the stator voltage constant.This paper proposes an active disturbance rejection control(ADRC)scheme to control the rotor-side,grid-side and DVR-side converters in a wind–DVR integrated network.The performance of the Type-3 WT with DVR topology is evaluated under various test conditions using MATLAB®/Simulink®.These simulation results are also compared with the experimental results for the LVRT capability performed on a WT emulator equipped with a crowbar and direct current(DC)chopper.The simulation results demonstrate a favourable transient and steady-state response of the Type-3 wind turbine quantities defined by the LVRT codes,as well as improved reactive power support under balanced fault conditions.Under the most severe voltage drop of 95%,the stator currents,rotor currents and DC bus voltage are 1.25 pu,1.40 pu and 1.09 UDC,respectively,conforming to the values of the LVRT codes.DVR controlled by the ADRC technique significantly increases the LVRT capabilities of a Type-3 doubly-fed induction generator-based WT under symmetrical voltage dip events.Although setting up ADRC controllers might be challenging,the proposed method has been shown to be extremely effective in reducing all kinds of internal and external disturbances.
文摘1.General ReviewThe rapid development of extra high voltage transmissionlines and power systems raised serious stability problems.Becauseof the long distance transmission of power and relative weak systemconfiguration,stability became the most important and seriousproblems.The risks in terms of disturbance causing subsequentsystem instability could be very high and the results of frequency andvoltage collapse may cause catastrophic results.
