大型变压器差动保护

本文分析了超高压大容量变压器构成差动保护的特征及实施方案,本装置中由于采用了性能较好的有源滤波器,电路中将运算放大器和CMOS门电路混合使用,差动保护的动作时间接近半个周波。差动保护由比率制动、二次谐和五次波制动,差动速断等部分构成。对不带负荷调压的变压器动作电流为0.1倍额定电流。既是相间短路保护、匝间短路和单相接地保护,也可兼作过电压保护。装置中设有电流互感器二次回路断线闭锁。

High-Power Transformer Differential Relay

The character and scheme of differential protection of high-power transformers are analysed. This kind of relay is constituted by active filters, integrated operational amplifier, CMOS circuit etc. The operating time approaches to 10 ms. The protection consists of percentage, 2nd, 5th harmonic restraint, differential cut-off, broken wire interlocking. This relay is both an interphase fault, turn-to-turn, single earth fault protection and an overvoltage protection. The pick-up current is 0.1 I_(non) of the transformer.