变压器保护新原理

变压器通常采用纵差动保护作为主保护,纵差动保护会受到励磁涌流的影响而误动作。目前已有很多识别励磁涌流的方法,但都有其局限性,不能绝对可靠地区分励磁涌流和空投于故障变压器的短路电流。该文提出了一种不受空投时励磁涌流影响的变压器差动保护原理,并用阻抗原理反应空投于内部故障。这种保护配置在内部故障时有很高的灵敏度,在外部故障时又有很强的制动作用,不反映空投时的励磁涌流,却能反映变压器空载合闸时有故障的情况,解决了变压器差动保护的难题。

New principle of transformer protection

Differential protection generally is used as main protection of transformers. Because of the influence of inrush exciting current, differential protection may maloperate. There are some ways to detect inrush exciting current, but they are limited by distinguis- inrush exciting current from short circuit current when closing on faulted transformer in different system operating conditions. This paper introduces a new approach to transformer protection which combines current differential protection and impedance protection, The proposed current differential protection is immune to inrush exciting current and the impedance protection is used to detect internal fault of transformer when closing, This principle has high sensitivity on internal fault and high restraining function during external fault as well, It doesnt reflect on inrush current but can operate when closing onto faulted transformer,