基于等效瞬时漏感与回路方程的变压器保护原理

A Novel Principle of Transformer Protection Based on Equivalent Instantaneous Leakage Inductance and Loop Equation

在变压器回路方程的基础上,提出一种利用等效瞬时漏电感实现变压器保护的新方法。该方法不依赖于变压器铭牌上的短路电抗等参数,能实时监测变压器各侧漏电感的变化情况。因此,通过计算等效瞬时漏感参数,可同时提高变压器保护的灵敏性和可靠性。该方法计算量小,对三绕组变压器同样适用。两套动模试验分析结果表明,该原理不受励磁涌流的影响,能够可靠、迅速的切除变压器内部故障,对轻微故障也有足够的灵敏度。

On basis of transformer loop equation, a novel principle of transformer protection using equivalent instantaneous leakage inductance is presented. The principle is independent of short-circuit reactance and leakage inductance of each side can be effectively monitored in real time. Therefore, sensitivity and reliability of transformer protection can both be improved by calculating equivalent instantaneous leakage inductance. The principle is also applicable for three- winding transformer. Dynamic testing results verify this scheme that has been stable during inrush current and is able to reliably and quickly clear internal fault even fault is light.