整流侧直流电压异常波动的影响及其改进建议

南方电网某直流输电系统因整流侧高压直流电压异常波动引起阀保护性触发功能动作造成数次停运。分析显示，这种直流电压异动会导致严重的后果：在换流变分接开关定Udi0控制的作用下引起触发角降至最小触发角（5°），逆变侧转为定电流控制，最终由于启动保护性触发功能的换流阀数量超过了设定值以致直流系统停运。为了从根本上解决这一问题，需要对直流线路电压测量系统进行改造。

The Affection of DC Voltage Abnormal Fluctuation on Rectifier Side and Its Improvement Advice

For an HVDC transmission system in China Southern Power Grid, its DC voltage abnormal fluctuaton on rectifier side have caused several times trip of the system. The analysis in this paper shows that the affection of DC voltage abnormal fluctuation could be so serious as to lead the thyristor trig angle to the minimun (5 ) due to the tap-changer Udi0 control, and then to shift the control to current control mode, and finally to cause the DC system tripping as the number of thyristors for protection breakover dioder (BOD) function reached the threshold. To solve the problem, it must be done to reform the DC voltage measurment system.