HVDC送端交流系统故障暂态过电压评估指标

特高压直流输电系统直流闭锁故障及交流系统短路故障引起的暂态过电压,对系统稳定性造成严重冲击。量化评估交直流系统暂态性能指标,对确定交直流电力系统规划设计和调度运行具有指导意义。对交流系统暂态过电压机理进行分析,推导出基于无功补偿和短路比的暂态过电压计算方法,基于系统短路比与补偿电容和交流滤波器参数的比值定义了暂态电压评估指标R_r。研究表明,随着该暂态电压评估指标R_r减小,系统故障后送端换流母线暂态电压升高,受端也会发生不同程度的换相失败。最后,基于国际大电网会议直流标准测试系统,验证了所提指标的有效性。

Evaluation Index of Transient Overvoltage During Fault at HVDC Sending-End AC System

The transient overvoltage caused by the DC blocking fault of the UHVDC transmission system and the short-circuit fault of the AC system has a serious impact on the stability of the system. Quantitative assessment of the transient performance index has important guiding significance for the dispatching operation of AC/DC power system. This paper analyzes the mechanism of transient overvoltage in AC system, deduces the calculation method of transient overvoltage on the basis of reactive power compensation and short-circuit ratio, and then defines the transient voltage evaluation index R_r. Research shows that, as the index R_r decreases, the transient voltage of the commutation bus at the sending end will increase after a system fault, and commutation failures will also occur at the receiving end. Finally, on the basis of the CIGRE benchmark HVDC standard test system, the effectiveness of the proposed index R_r is verified.