直流滤波器高压电容器接地故障保护判据和方案

摘要

The earth fault in the high-voltage capacitor of direct current(DC)filter will greatly affect the security and stable operation of DC transmission system.The existing high-voltage capacitor earth fault protection of DC filter has the problems of poor selectivity,low sensitivity,difficult setting of definite value and so on.A new type of high-voltage capacitor earth fault protection criterion and protection scheme,which is independent of the system operating conditions,is proposed based on the requirements of DC transmission system and DC filter high-voltage capacitor protection.The proposed fault protection criterion and scheme is acquired by combining with the structural characteristics of H-type high-voltage capacitor and simplifying the earth fault model.The problems in the existing protection are solved by the proposed scheme.The actual ultra-high-voltage direct current(UHVDC)engineering simulation model is used to simulate the high-voltage capacitor earth fault.The validity and correctness of the proposed protection criterion and scheme are verified.%直流滤波器高压电容器发生接地故障对直流输电系统的安全、稳定运行影响巨大,现有的直流滤波器高压电容器接地故障保护方法存在选择性差、灵敏度低、定值整定困难等问题.立足于直流输电系统和直流滤波器高压电容器保护的需求,结合常用的 H 型高压电容器的结构特点,简化接地故障模型,提出了不依赖运行工况的新型高压电容器接地故障保护判据和保护方案,解决了现有保护存在的问题.使用实际的特高压工程仿真模型模拟高压电容器接地故障,验证了提出的保护判据和方案的有效性和正确性.