预防220kV变压器受短路冲击损坏事故的一种措施

Study and Application on Measures for Protecting 220 kV Transformer from Short-Circuit Faults

当220kV变电站的110kV侧发生单相接地故障时,有可能造成主变压器遭受冲击而损坏。通过分析变压器绕组的抗短路能力,发生单相接地故障时流入变压器的短路电流,可知国产老旧变压器极易受到短路电流的冲击而损坏。文章以唐山供电公司的3个变电站为实例,介绍了一种通过改变主变压器中性点的接地方式,即在主变压器110kV中性点加装小电抗器,减小单相故障时的接地短路电流及流入主变压器绕组的短路电流,从而保护主变压器的措施,改造的效果是比较好的。

The main transformer in 220 kV substation may be damaged by short circuit current, when there is a single-phase grounding fault occurred in the 110 kV Side. Through analyzing the short-circuit withstand ability of transformer winding and the short-current that feed into the transformer, it is found out that the old transformers can be damaged easily by single-phase grounding fault. Taken three substations in Tangshan Power Supply Co. as an example, the paper introduced the measure to reduce the short-current that feed into the transformer when the single-phase gounding fault occurred, which is through changing the grounding mode of transformer neutral and adding small reactor in 110 kV neutral of main transformer. This measure can protect main transformers in 220 kV transformer substation effectively.