电力系统近振荡中心换相失败分析与仿真

Analysis and Simulation of Commutation Failure near Oscillation Center in Power System

针对高压直流输电系统受端三相接地故障线路切除后的换相失败问题,从机理角度阐述切除大容量机组近区三相接地故障线路后的机组功角振荡过程及功角振荡特性,分析振荡中心近区电压变化特征、振荡中心近区换流站换相失败的风险并推广至线路任意直流落点,总结定熄弧角控制降低振荡中心近区换流站换相失败风险的关键影响因素。仿真结果表明理论分析的正确性。

Aimed at the commutation failure problem in a HVDC transmission system at its receiving end after a line un⁃der three-phase grounding fault is cut off,the power-angle oscillation process of the unit and the corresponding oscilla⁃tion characteristics after cutting off the line near the large capacity unit are expounded from the perspective of mecha⁃nism analysis.The voltage variation characteristics near the oscillation center are analyzed,and the risk of commutation failure of a converter station near the oscillation center is discussed,which is further extended to any DC drop point on the line.In addition,the key influencing factors for reducing the risk of commutation failure by the constant extinction angle control are summarized.Simulation results verify the theoretical analysis performed in this paper.