摘要
变压器差动保护中传统的二次谐波制动方案在变压器空载合闸、内部故障或外部故障切除时,若TA饱和,变压器差流中二次谐波含量较低,差动保护容易误动。文章首先分析了变压器空载合闸中励磁涌流的二次谐波和基波之间的幅值关系,利用二次谐波制动的原理防止励磁涌流造成差动保护误动作,这也是目前最普遍应用的方法。通过建立合理的变压器模型,在不同的情况下进行各种二次谐波仿真、比较,验证了其可靠性与正确性。
The traditional transformer differential protection scheme of second harmonic brake in transformer no-load closing,internal fault and external fault removal,if TA saturation,second harmonic content in the transformer differential current is low,the differential protection misoperation easily. This paper analyzes the excitation inrush current in the transformer no-load closing between fundamental and second harmonic amplitude relationship,using the principle of second harmonic brake to prevent the excitation inrush current differential protection misoperation. This is by far the most widely used method. Through establishing reasonable model of transformer in different situations are compared,and all kinds of second harmonic simulation,verified its reliability and validity.
引文
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