电压源型直流输电系统(voltage source converter based high voltage direct current,VSC-HVDC)并入弱交流电网可能产生振荡失稳现象,严重威胁电力系统安全稳定运行。VSC-HVDC结构日渐复杂,系统中同时存在多种控制策略,针对多端、多控...电压源型直流输电系统(voltage source converter based high voltage direct current,VSC-HVDC)并入弱交流电网可能产生振荡失稳现象,严重威胁电力系统安全稳定运行。VSC-HVDC结构日渐复杂,系统中同时存在多种控制策略,针对多端、多控制策略下VSC-HVDC的稳定特性还需深入研究。针对上述问题,以定直流电压/定功率混合控制的双受端VSC-HVDC系统为研究对象,探讨了系统在不同电网条件下的稳定特性。首先,分别推导了定直流电压/定功率控制策略VSC-HVDC子系统的数学模型和小信号模型,依据交直流拓扑关系构建混合控制策略下的全系统模型;其次,搭建双受端VSC-HVDC系统电磁暂态模型验证了不同运行工况下小信号模型的准确性;最后,分析了交流系统强度及联络线长度对双受端VSC-HVDC系统稳定性的影响,获得了定直流电压/定功率VSC-HVDC系统所能接受的最小电网强度,形成了系统安全稳定运行空间,并且基于MATLAB/Simulink时域仿真验证了理论分析的正确性。展开更多
When multiple LCC-HVDC transmission lines are densely fed into a receiving AC system,voltage dips can easily propagate in the power system,resulting in multiple LCC commutation failures simultaneously.The VSC-HVDC can...When multiple LCC-HVDC transmission lines are densely fed into a receiving AC system,voltage dips can easily propagate in the power system,resulting in multiple LCC commutation failures simultaneously.The VSC-HVDC can be used to divide the receiving sys-tem into several interconnected sub-partitions and improve the voltage support capability of the receiving system.Compared with asyn-chronous interconnection,which completely separates the receiving systems with VSC-HVDC,incomplete segmentation with an AC connection is a more pertinent segmenting method for multilayer complex regional power grids.To analyze the voltage support capability of the VSC in incomplete segmentation,a micro-incremental model of the VSC was established,the operating impedance of the VSC was calculated,and the voltage support function of the VSC was quantified.The effect of the fault on the system short-circuit capacity was analyzed,and a calculation method for the multi-infeed short-circuit ratio in an incompletely segmented scenario was obtained.A VSC-segmented model of a two-infeed DC system was built on the EMTDC/PSCAD simulation platform,and the validity of the micro-increment model and accuracy of the proposed conclusions were verified.展开更多
针对含柔性直流输电(voltage source converter-high voltage direct current,VSC-HVDC)的交直流系统电压稳定性问题,开发出一种适用于含VSC-HVDC的交直流系统连续潮流程序,以负荷裕度指标分析VSC-HVDC系统有功功率传输方向、有功功率...针对含柔性直流输电(voltage source converter-high voltage direct current,VSC-HVDC)的交直流系统电压稳定性问题,开发出一种适用于含VSC-HVDC的交直流系统连续潮流程序,以负荷裕度指标分析VSC-HVDC系统有功功率传输方向、有功功率传输容量及换流站与交流系统无功功率交换量的变化对系统电压稳定性的影响。进而利用系统电压崩溃点处雅可比矩阵,推导出系统负荷裕度对VSC-HVDC有功功率控制参数和无功功率控制参数的灵敏度,并基于该灵敏度提出一种适用于改善系统电压稳定性的VSC-HVDC调控策略。最后,将所提方法应用于修改的68节点和IEEE118节点交直流系统,仿真结果验证了所提方法的正确性和有效性。展开更多
文摘电压源型直流输电系统(voltage source converter based high voltage direct current,VSC-HVDC)并入弱交流电网可能产生振荡失稳现象,严重威胁电力系统安全稳定运行。VSC-HVDC结构日渐复杂,系统中同时存在多种控制策略,针对多端、多控制策略下VSC-HVDC的稳定特性还需深入研究。针对上述问题,以定直流电压/定功率混合控制的双受端VSC-HVDC系统为研究对象,探讨了系统在不同电网条件下的稳定特性。首先,分别推导了定直流电压/定功率控制策略VSC-HVDC子系统的数学模型和小信号模型,依据交直流拓扑关系构建混合控制策略下的全系统模型;其次,搭建双受端VSC-HVDC系统电磁暂态模型验证了不同运行工况下小信号模型的准确性;最后,分析了交流系统强度及联络线长度对双受端VSC-HVDC系统稳定性的影响,获得了定直流电压/定功率VSC-HVDC系统所能接受的最小电网强度,形成了系统安全稳定运行空间,并且基于MATLAB/Simulink时域仿真验证了理论分析的正确性。
基金supported by the State Grid Science and Technology Project 5108-202218280A-2-87-XG.
文摘When multiple LCC-HVDC transmission lines are densely fed into a receiving AC system,voltage dips can easily propagate in the power system,resulting in multiple LCC commutation failures simultaneously.The VSC-HVDC can be used to divide the receiving sys-tem into several interconnected sub-partitions and improve the voltage support capability of the receiving system.Compared with asyn-chronous interconnection,which completely separates the receiving systems with VSC-HVDC,incomplete segmentation with an AC connection is a more pertinent segmenting method for multilayer complex regional power grids.To analyze the voltage support capability of the VSC in incomplete segmentation,a micro-incremental model of the VSC was established,the operating impedance of the VSC was calculated,and the voltage support function of the VSC was quantified.The effect of the fault on the system short-circuit capacity was analyzed,and a calculation method for the multi-infeed short-circuit ratio in an incompletely segmented scenario was obtained.A VSC-segmented model of a two-infeed DC system was built on the EMTDC/PSCAD simulation platform,and the validity of the micro-increment model and accuracy of the proposed conclusions were verified.
文摘针对含柔性直流输电(voltage source converter-high voltage direct current,VSC-HVDC)的交直流系统电压稳定性问题,开发出一种适用于含VSC-HVDC的交直流系统连续潮流程序,以负荷裕度指标分析VSC-HVDC系统有功功率传输方向、有功功率传输容量及换流站与交流系统无功功率交换量的变化对系统电压稳定性的影响。进而利用系统电压崩溃点处雅可比矩阵,推导出系统负荷裕度对VSC-HVDC有功功率控制参数和无功功率控制参数的灵敏度,并基于该灵敏度提出一种适用于改善系统电压稳定性的VSC-HVDC调控策略。最后,将所提方法应用于修改的68节点和IEEE118节点交直流系统,仿真结果验证了所提方法的正确性和有效性。
