基于辅助电压判据的柔性直流换流阀子模块旁路拒动策略

Bypass Switch Rejection Strategy of Sub-module in Flexible DC Converter Valve Based on Auxiliary Voltage Criterion

摘要:

为解决柔性直流输电换流站换流阀子模块旁路开关拒动导致直流闭锁，首先，开展了旁路开关动作原理和动作过程力学分析；接着，从现场检查、故障录波和旁路开关合闸故障复现试验3个方面，深入分析某换流阀子模块旁路拒动事件的故障原因。然后，针对无转折晶闸管子模块设计的在运工程，提出基于辅助电压判据的旁路开关拒动改进设计策略；最后，根据4种不同运行工况分别开展改进设计策略试验验证。结果表明，所提改进设计策略具有可靠性和有效性，该策略实施后避免了旁路开关拒动导致换流阀子模块炸裂和换流阀闭锁，进一步提高了在运柔性直流输电工程换流阀子模块运行可靠性。

Abstract:

In order to solve the problems of flexible DC blocking caused by the failure of bypass switch of sub-module in flexible converter stations, the action principle and force analysis of bypass switch action process are carried out. Next, from three aspects, that is, on-site inspection, fault recording and the recurrence test of bypass switch closing fault, the fault causes for bypass failure event of a flexible DC sub-module is analyzed in depth.And then, an improved design strategy for bypass switch rejection based on auxiliary voltage criteria is proposed for the non-turning thyristor module. At the last, the effectiveness and reliability of the improved strategy is verified through experiments under four different operating conditions,which avoids the sub-module cracking and converter valve blocking, and further improves the reliability of sub-module operation in flexible HVDC engineering in operation.