传统高压直流输电换流阀及其常发故障分析

Analysis of Traditional HVDC Converter Valve and Its Frequent Faults

金中直流输电工程逆变站采用典型的传统高压直流输电技术,使用ABB技术路线的换流阀,却比国内同类型的高压直流输电工程多发IP(Indicating Pulse ,指示脉冲)丢失、 IP震荡、保护性触发等异常现象。为此,对换流阀结构、 VCU(Valve Control Unit ,阀控单元)配置、晶闸管编码进行了分析,初步确定晶闸管单元硬件问题为频繁IP告警的重要原因之一。测试晶闸管后进一步对TCU(Thyristor Control Unit ,晶闸管控制单元)取能电路进行分析、检测,认为稳压二极管、功率三极管异常均有可能导致TCU处于保护性触发模式,并建议设计一种针对TCU控制单元的专项测试,为高压直流输电工程的安全运行提供保障。

The inverter station of Jinzhong HVDC transmission engineering is a typical traditional high-voltage direct current transmission. It adopts the ABB technical route converter valve, but it has more abnormal phenomena such as IP loss, IP oscillation and protective trigger than the same type of HVDC transmission project in China. The structure of converter valve, VCU configuration and thyristor coding were analyzed. It was preliminarily determined that the hardware problem of thyristor unit was one of the important reasons for frequent IP alarm. After the thyristor test, the TCU energy storage circuit was further analyzed and detected. It was considered that the Zener diode and the power triode abnormality may cause the TCU to be in the protective trigger mode. A special test for the TCU control unit to provide a guarantee for the safe operation of the HVDC transmission project was suggested.