500 kV高压直流断路器支架绝缘设计

Research on Insulation Design of 500 kV DC Circuit Breaker Support

我国正在建设500 kV张北柔性直流电网试验示范工程,500kV高压直流断路器是张北柔性直流电网的核心装备,其支架绝缘设计决定了断路器的经济性及安全性。根据经验设计了支架初始结构,建立了其电场仿真三维模型,采用ANSYS有限元仿真软件计算了初始支架表面电场分布,获得了支架表面场强集中点,针对场强集中点提出了电场分布优化方案。搭建了断路器支架试验平台(海拔约50 m),开展了不同电极和电压极性下支架操作冲击50%放电试验,获得了不同电极下支架的间隙系数,验证了电场优化方案的正确性。结合支架操作冲击50%放电试验结论,针对张北直流电网工程绝缘水平要求,估算了支架对地最小空气间隙,最小空气间隙设计为4.7 m。论文工作为工程样机设计提供了参考。

Zhangbei pilot 500 kV flexible DC grid project is under construction.500 kV DC circuit breaker is a core device in this project.The insulation design of DC circuit breaker’s support affects economy and safety.Based on existing experience,an initial structure of the support is designed.A simulation model for electric field of the support is established,and the distribution law of the electric field is obtained with ANSYS software.The concentrated points of electric field are found and an electric field optimization scheme is proposed.A test platform of the support is built(at about 50 m altitude).Switch impulse 50%discharge test of the support for different electrodes and voltage polarities are carried out and the gap coefficient of the support is obtained.On basis of the insulation level of Zhangbei DC grid and the result of the switch impulse discharge test,the shortest air clearance of the support is calculated with the result of 4.7 m.This paper provides a reference for engineering prototype design.