柔性直流输电功率模块过压保护误动原因分析及优化

针对鲁西柔性直流输电工程中换流器频繁发生功率模块过压保护误动的情况,提出一种防范功率模块过压保护误动的优化策略。分析功率模块在故障前后及旁路开关闭合前后的工作原理,剖析保护误动案例,阐述功率模块过压保护策略存在的电压测量采样异常导致换流器跳闸的风险,提出增加判断旁路开关是否发生拒动的防误判据。该优化策略在功率模块控制板中实现,可有效避免阀控层设备误判、误动作的风险。通过仿真验证了所提优化策略的有效性和可行性,目前该策略已在鲁西柔性直流输电工程中实际应用,取得了良好的效果。

Reason Analysis and Optimization on Over-voltage Protection Mal-operation of Power Modules in VSC-HVDC

In view of frequent over-voltage protection mal-operation of power modules of the converters in LuXi VSC-HVDC project,this paper proposes an optimal strategy to prevent over-voltage protection from malfunction of the power modules.It analyzes working principles of the power module before and after faults,as well as closing and opening of the bypass switch.It also analyzes cases of over-voltage protection mal-operation,and states tripping risk of the converter caused by abnormal voltage measurement in the over-voltage protection strategy for the power module.Afterwards,it presents anti-mistake criterion for mal-operation of the bypass switch.The optimized strategy is implemented in the power module control board,which is effective in avoiding the risk of misjudgment and malfunction of the high level control equipment.The paper verifies effectiveness and feasibility of the proposed optimization strategy by simulation.This strategy has been applied in LuXi project already and has good effect.