750kV串抗并联避雷器泄漏电流表指示异常分析研究

针对一起换流站串抗避雷器的电流泄漏电流表出现指针异常满偏问题进行故障诊断,理论分析可能引起泄漏电流表指示异常的原因,通过开展一系列对比试验并结合建模仿真,重点研究了外界磁场和异常高电压对电流泄漏电流表指针偏转的影响,结果表明泄漏电流表指针偏转与串抗周围强磁场环境无关,而与其下引线处异常高电压有关。经综合分析,确定该电流泄漏电流表同避雷器并接于线路串抗两侧,其下引线处因无法接地而存在异常高电压是引起指针异常满偏的主要原因,随后提出处理建议。

Analysis on indication abnormality of current leakage ammeter for 750 k V series reactor shunt arrester

By the faulty diagnosis of the leakage ammeter appearing the abnormal full deviation of the pointer in a converter station, the reason of abnormal indication of the leakage ammeter was theoreti- cally analyzed. Through a series of comparative experiments and modeling simulation, the influence of external magnetic field and abnormal high voltage on the pointer deflection of the leakage ammeter was emphatically studied. The results show that the pointer deflection of the leakage ammeter has nothing to do with the resistance to the strong magnetic field, but has something to do with the abnormal high voltage at the lower lead. By comprehensive analysis, it is determined that the current leakage ammeter and arrester are connected in parallel on both sides of the line series reactor. The lower lead has no way of grounding leading to an unusually high voltage which is the main cause of abnormal pointer full deviation, and the treatment suggestions were put forward.