柔直阀用双重保护晶闸管设计及试验研究

Design and Experimental Study of Double Protection Thyristor for Flexible and Direct Valves

半桥型柔性直流系统在直流故障及旁路开关拒动情况下,极易引起IGBT器件的损坏。电压、电流双重保护晶闸管具备故障分流及旁路功能,对提升半桥型柔性直流系统运行安全至关重要。研究了电压电流双重保护晶闸管工作原理,获取短路分流和击穿引流的功能设计需求,结合电热应力分析提出了保护晶闸管的选型原则,最后以±800 kV/8 000 MW的半桥结构样机进行试验验证,证明了保护晶闸管设计与试验研究的正确性。

In the case of DC failure and bypass switch rejection,the half-bridge flexible DC system is easy to cause IGBT component damage and even system outage.The thyristor with voltage and current dual protection has the func-tion of fault shunt and bypass,which is very important to improve the operation safety of half-bridge flexible DC sys-tem.The working principle of the thyristor with voltage and current dual protection is studied,and the functional de-sign requirements of short circuit shunt and breakdown drainage are obtained.The selection principle of the thyristor is proposed based on the analysis of electric heating stress.Finally,the validity of the design and experimental study of the thyristor is verified by the test with the±800 kV/8000 MW half-bridge prototype.