换流阀EOC信号延迟原因分析及解决措施

Reason Analysis and Solution of EOC Signal Delay of Converter Valve

某逆变站由于换流阀TVM板运行情况不稳定,在直流运行过程中负向脉冲宽度减小,TVM板与阀控VBE信号失配,导致换流阀电流过零(Extinction Of Current,EOC)信号延迟。通过分析和测试TVM的原理,发现其负向脉冲宽度减小的原因为TVM板脉宽控制回路中的X7R型电容固有工作特性运行不稳定。将TVM板电容更换为工作稳定的C0G型电容,通过各项试验合格后,将原TVM板全部更换为新TVM板,直流运行稳定,成功解决了因换流阀EOC信号延迟引起直流换相失败的问题。

Due to the unstable operation of the TVM board of the converter valve,the negative pulse width of the inverter station decreases during the DC operation,and the mismatch between the TVM board and the VBE signal of the valve control results in the delay of the EOC signal of the converter valve.Through the analysis and test of the principle of TVM,it is found that the reason for the decrease of negative pulse width of TVM is that the inherent working characteristics of the X7R capacitor in the pulse width control circuit of TVM board are not stable.After replacing the TVM board capacitor with the c0g capacitor,the DC operation is stable after the original TVM board is replaced with the new TVM board,and the EOC signal of the converter valve is successfully solved Delay causes the failure of DC commutation.