基于等效瞬时漏电感的变压器保护新原理

Novel Principle of Power Transformer Protection Based on Equivalent Instantaneous Leakage Inductance

在变压器模型回路方程的基础上,应用等效瞬时漏电感,提出了一种新型变压器保护原理。在内部故障的情况下,绕组变形将会导致漏电感参数发生变化;而在正常运行、外部故障和励磁涌流情况下,变压器漏电感等内部结构参数不会发生改变。因此,通过计算等效瞬时漏感参数,可有效地识别变压器的运行状态。2组动模试验分析结果表明,该原理不受励磁涌流的影响,能够迅速、可靠地切除变压器内部故障,对轻微故障也有足够的灵敏度。

A novel principle of transformer protection using equivalent instantaneous leakage inductance, based on the transformer model loop equation, is proposed. The winding deformation can result in the change of the parameters of leakage inductance during internal fault. No change, however, takes place under conditions of normal operation, external fault and magnetizing inrush current. Therefore, the operation states of transformer can be effectively distinguished by calculating the equivalent instantaneous leakage inductance. Two groups of dynamic experimental results have verified that the method proposed is free from the impact of inrush current and is capable of clearing the internal fault as well as the light fault quickly and reliably.