特高压直流分层接入换相失败电压判断与仿真

Voltage judgment and simulation of commutation failure under UHVDC hierarchical access

为了判断分层接入模式下特高压直流是否发生换相失败,阐述了导致换相失败的原因,根据电压跌落后最大直流电流对应的熄弧角推导了发生换相失败时的电压临界值,在CIGRE基础上搭建了分层接入PSCAD的直流模型,用PSD-BPA在华东电网夏季运行方式下对锡盟-泰州逆变侧进行了实际故障仿真,得到了直流电压、熄弧角等曲线。仿真分析结果表明,特高压直流换相失败可以通过电压瞬时跌落值来判断,熄弧角曲线与理论计算值一致,用高低压阀组两个熄弧角的最小值来判断是否发生换相失败是正确的,推导的电压阈值能为实际工程中换相失败预测模块的整定提供参考。

In order to judge whether the commutation failure occurs in UHVDC under the mode of hierarchical ac-cess ,the reason of commutation failure is expounded and the voltage threshold at the time of commutation failure is deduced according to the maximum DC current after the voltage drop. Then a DC model of hierarchical access to PSCAD is established based on CIGRE, and the actual failure simulation on Ximeng - Taizhou inverter side is car-ried out on PSD - BPA under the operating mode of East China Power Grid in summer, thus receiving the curves such as DC voltage and the arc extinguishing angle. The simulation results show that the UHVDC commutation fail-ure can be judged by the instantaneous drop of voltage, the arc extinguishing curve is consistent with the theoretical calculation and the minimum values of the two arc extinguishing angles of the high and low pressure valve sets can be used to determine whether it is correct that commutation failure occurs. Therefore, the deduced voltage threshold can provide a reference for the setting of commutation failure prediction module in the actual engineering.