特高压直流输电工程中性母线开关故障处理策略优化

Optimization of Treatment for Neutral Bus Switch Faults in UHVDC Transmission Projects

特高压直流输电工程采用双极共用接地极设计,一个极故障闭锁后需通过极隔离操作实现故障极与运行极的隔离。极隔离操作过程中,如果极中性母线开关发生故障无法分开导致极隔离中断,需配置极中性母线开关故障处理策略继续完成极隔离。根据不同直流故障时对应的工况,分析了中性母线开关故障处理策略存在的不足,基于故障特性优化了故障处理策略,最后通过RTDS仿真试验验证了策略优化的有效性。

UHVDC transmission projects adopt the design of grounding electrode sharing between the two poles,which makes pole isolation necessary to separate faulty pole from operating pole when one of the poles encounters a fault.In the process of pole isolation,if the pole neutral bus switch(NBS)cannot correctly perform disconnection due to the fault,a pre-scheduled NBSF strategy is needed to complete pole isolation.This paper analyzes the shortcomings of NBSF strategy according to operating conditions corresponding to various types of DC faults,optimizes the NBSF strategy based on fault characteristics,and verifies effectiveness of the optimized strategy through RTDS simulation experiments.