大型变压器内部放电故障实例诊断与分析

Diagnosis and Analysis of an Internal Discharge Fault in Large Transformer

为了能在放电故障发展的初始阶段发现并监测其发展过程,及时分析判断其故障状态和严重程度,从而提高运行的可靠性,笔者针对几种常用局部放电监测方法的不足,通过油中溶解气体分析及相关电气试验,准确判断了某大变压器的内部放电性质、严重程度及可能发生的大致部位。利用脉冲电流法和超声波检测法的综合运用,成功地检测了该变压器的内部放电故障、发展趋势,并精确地进行了故障定位,在进人检查时上述方法判断和分析的结论得到了验证。

To find a discharge fault in a large transformer at the initial stage,monitor its evolution,judge the fault level,and enhance the reliability of the transformer,the authors accurately diagnosed the nature,level,and possible position of a internal discharge in a large transformer by analyzing the dissolved gas in oil and conducting electric tests.Furthermore,the evolution of the internal discharge fault was detected and the discharge was accurately positioned via combination of impulse current test and ultrasonic wave test.All the results were verified through visual checks inside the transformer.