利用TA差异性配置的主变故障点诊断分析

主变发生故障后,如何准确定位故障点,是目前困扰主变故障处理的一个难题。文中以一次500 kV主变故障处理过程为例,通过对保护动作信息与故障录波器录波信息的综合分析,发现主变高、中侧压套管故障电流在故障前、后的极性并没有变化,具备穿越性电流的特点,而采用独立电流互感器(TA)的差动保护检测到差流,差动保护动作,从而快速地判断短路故障点位于主变套管TA和独立TA之间,为主变故障检查与抢修提供了有益的参考。

Diagnosis and Analysis Methods of Main Transformer Fault Point Using Differences between TAs

How to accurately locate the failure point when the transformer fails makes the fault treatment difficult. Taking a fault treatment of 500 kV transformer as an example, the information of protective action and fault waveforms is analyzed comprehensively. The casing fault current in high-mid voltage side of the main transformer does not change its polarities before and after the fault and owns fide-through characteristics. However the differential protection using independent TA can detect the differential current and act, so it can determine that the short-circuit fault point is located between transformer casing TA and independent TA, and offer references for the fault maintenance of the transformer.