光电流互感器故障引发交流滤波器差动保护动作问题分析

Analysis of Undesired Trip of AC Filter Differential Protection Caused by Optical Current Transformer Fault

随着光电流互感器(纯光CT)越来越多地应用于特高压直流输电工程,纯光CT故障率也逐渐升高。介绍了某换流站因纯光CT电子单元故障引发交流滤波器小组差动保护动作跳闸的问题,分析了故障原因,定位故障于电子单元内,同时对故障电子单元进行实验室验证,确认故障根本原因为光源连接线接触不良导致光源驱动电流异常,造成输出光功率波动,并提出了整改意见。

The increasing application of optical current transformers(pure optical CT)in ultra-high voltage DC transmission projects results in gradual rise of fault rate of pure optical CT.This paper reports an undesired trip of AC filter group differential protection occurred in a converter station caused by a fault in optical CT electronic unit.The cause of the fault is analyzed,and the fault is located within the electronic unit.Furthermore,laboratory verification is conducted on the faulty electronic unit,confirming that the fault originates from poor contact of light source connection wire which leads to abnormal driving current of light source and fluctuations of output optical power.Finally the rectification suggestions are proposed.