Small signal instability may cause severe accidents for power system if it can not be dear correctly and timely. How to maintain power system stable under small signal disturbance is a big challenge for power system o...Small signal instability may cause severe accidents for power system if it can not be dear correctly and timely. How to maintain power system stable under small signal disturbance is a big challenge for power system operators and dispatchers. Time delay existing in signal transmission process makes the problem more complex. Conventional eigenvalue analysis method neglects time delay influence and can not precisely describe power system dynamic behaviors. In this work, a modified small signal stability model considering time varying delay influence was constructed and a new time delay controller was proposed to stabilize power system under disturbance. By Lyapunov-Krasovskii function, the control law in the form of nonlinear matrix inequality （NLMI） was derived. Considering synthesis method limitation for time delay controller at present, both parameter adjustment method by using linear matrix inequality （LMI） solver and iteration searching method by solving nonlinear minimization problem were suggested to design the controller. Simulation tests were carried out on synchronous-machine infinite-bus power system. Satisfactory test results verify the correctness of the proposed model and the feasibility of the stabilization approach.展开更多
为了演示和验证稳定器设计的就地相位补偿法在多机电力系统中的应用,介绍在多机电力系统中,就地补偿设计稳定器的2个应用实例。第1个实例是在多机电力系统中就地补偿设计电力系统稳定器（power system stabilizer,PSS）,阻尼电力系统局...为了演示和验证稳定器设计的就地相位补偿法在多机电力系统中的应用,介绍在多机电力系统中,就地补偿设计稳定器的2个应用实例。第1个实例是在多机电力系统中就地补偿设计电力系统稳定器（power system stabilizer,PSS）,阻尼电力系统局部模振荡。第2个实例是就地补偿设计附加在静态同步补偿器（static synchronous compensator,STATCOM）上的稳定器,抑制多机电力系统中的区域模振荡,并给出在一个16机电力系统中的应用计算和仿真结果。展开更多
光伏直流升压汇集系统中,DC/DC换流器内部LC电路与开关电路因阻抗匹配而产生谐振问题,从而导致系统稳定性变差甚至崩溃。针对换流器因阻抗匹配产生的谐振问题,提出了有源和无源阻尼协同控制以消除谐振的方法。首先,建立了在不同工况下...光伏直流升压汇集系统中,DC/DC换流器内部LC电路与开关电路因阻抗匹配而产生谐振问题,从而导致系统稳定性变差甚至崩溃。针对换流器因阻抗匹配产生的谐振问题,提出了有源和无源阻尼协同控制以消除谐振的方法。首先,建立了在不同工况下的换流器运行小信号阻抗模型。其次,利用阻抗比判据对比分析系统稳定性差异,并讨论了不同虚拟电阻对系统稳定性的影响。最后,通过将产生谐振峰值处的角频率点与其相邻正常角频率点的等效阻抗幅值之比限定为[0.95,1.15],将阻尼电阻值在最大功率点跟踪(maximum power point tracking,MPPT)控制下换流器的闭环输出阻抗幅值提高了约1.5倍。研究结果表明,相比仅采用有源或无源阻尼法,所提协同控制策略使得产生谐振处的幅值由–15 dB增加到40.5 dB,提高约4倍,且系统具有较大的幅值和相角裕度,可有效提高系统的稳定性。展开更多
随着我国风电装机容量与高速铁路运营里程不断增长,部分地区出现风电场与电气化铁路共同接入电网公共连接点(point of common coupling,PCC)的情况,将会引发一系列谐波不稳定问题。针对此类问题,对风电场与多车接入牵引网耦合系统进行...随着我国风电装机容量与高速铁路运营里程不断增长,部分地区出现风电场与电气化铁路共同接入电网公共连接点(point of common coupling,PCC)的情况,将会引发一系列谐波不稳定问题。针对此类问题,对风电场与多车接入牵引网耦合系统进行稳定性研究(为便于阐述,将牵引变电所、接触网与列车视为一个整体,称为牵引供电系统),建立了电网-牵引供电系统-风电场耦合系统导纳模型,并结合阻抗扫频验证了模型的准确性。接着分析了传输线路长度对电网-牵引供电系统-风电场耦合系统谐波稳定性的影响,并基于风电场、牵引供电系统的导纳Bode图进一步揭示了风电场和牵引供电系统交互影响的产生机理,并探究了耦合系统临界稳定时机车数量与风机数量比例条件。最后,基于Matlab/Simulink仿真和Starsim/HIL硬件在环仿真平台,验证了所建模型对电网-牵引供电系统-风电场耦合系统谐波不稳定现象研究的有效性和正确性。展开更多
基金Project(51007042)supported by the National Natural Science Foundation of China
文摘Small signal instability may cause severe accidents for power system if it can not be dear correctly and timely. How to maintain power system stable under small signal disturbance is a big challenge for power system operators and dispatchers. Time delay existing in signal transmission process makes the problem more complex. Conventional eigenvalue analysis method neglects time delay influence and can not precisely describe power system dynamic behaviors. In this work, a modified small signal stability model considering time varying delay influence was constructed and a new time delay controller was proposed to stabilize power system under disturbance. By Lyapunov-Krasovskii function, the control law in the form of nonlinear matrix inequality （NLMI） was derived. Considering synthesis method limitation for time delay controller at present, both parameter adjustment method by using linear matrix inequality （LMI） solver and iteration searching method by solving nonlinear minimization problem were suggested to design the controller. Simulation tests were carried out on synchronous-machine infinite-bus power system. Satisfactory test results verify the correctness of the proposed model and the feasibility of the stabilization approach.
文摘为了演示和验证稳定器设计的就地相位补偿法在多机电力系统中的应用,介绍在多机电力系统中,就地补偿设计稳定器的2个应用实例。第1个实例是在多机电力系统中就地补偿设计电力系统稳定器（power system stabilizer,PSS）,阻尼电力系统局部模振荡。第2个实例是就地补偿设计附加在静态同步补偿器（static synchronous compensator,STATCOM）上的稳定器,抑制多机电力系统中的区域模振荡,并给出在一个16机电力系统中的应用计算和仿真结果。
文摘光伏直流升压汇集系统中,DC/DC换流器内部LC电路与开关电路因阻抗匹配而产生谐振问题,从而导致系统稳定性变差甚至崩溃。针对换流器因阻抗匹配产生的谐振问题,提出了有源和无源阻尼协同控制以消除谐振的方法。首先,建立了在不同工况下的换流器运行小信号阻抗模型。其次,利用阻抗比判据对比分析系统稳定性差异,并讨论了不同虚拟电阻对系统稳定性的影响。最后,通过将产生谐振峰值处的角频率点与其相邻正常角频率点的等效阻抗幅值之比限定为[0.95,1.15],将阻尼电阻值在最大功率点跟踪(maximum power point tracking,MPPT)控制下换流器的闭环输出阻抗幅值提高了约1.5倍。研究结果表明,相比仅采用有源或无源阻尼法,所提协同控制策略使得产生谐振处的幅值由–15 dB增加到40.5 dB,提高约4倍,且系统具有较大的幅值和相角裕度,可有效提高系统的稳定性。
文摘随着我国风电装机容量与高速铁路运营里程不断增长,部分地区出现风电场与电气化铁路共同接入电网公共连接点(point of common coupling,PCC)的情况,将会引发一系列谐波不稳定问题。针对此类问题,对风电场与多车接入牵引网耦合系统进行稳定性研究(为便于阐述,将牵引变电所、接触网与列车视为一个整体,称为牵引供电系统),建立了电网-牵引供电系统-风电场耦合系统导纳模型,并结合阻抗扫频验证了模型的准确性。接着分析了传输线路长度对电网-牵引供电系统-风电场耦合系统谐波稳定性的影响,并基于风电场、牵引供电系统的导纳Bode图进一步揭示了风电场和牵引供电系统交互影响的产生机理,并探究了耦合系统临界稳定时机车数量与风机数量比例条件。最后,基于Matlab/Simulink仿真和Starsim/HIL硬件在环仿真平台,验证了所建模型对电网-牵引供电系统-风电场耦合系统谐波不稳定现象研究的有效性和正确性。
