摘要
500 kV变压器是连接两个甚至三个不同电压等级的重要电气一次设备。变压器空载合闸时,由于瞬时电压过大,可能造成变压器铁心饱和,引发严重的励磁涌流现象;同时500 kV变压器容量较大,励磁涌流衰减缓慢。本文以铜梁地区某一新建500 kV变压器为例,建立了适用于实际工程的变压器UMEC模型,通过PSCAD/EMTDC仿真计算,分析了500 kV变压器空载合闸时合闸断路器、电容式电压互感器、以及变压器励磁特性对励磁电流的影响,并提出了抑制励磁涌流的有效措施。
The 500 kV transformer is an important electrical equipment connecting two or even three different voltage levels. When the no-load transformer is closed, the transient voltage increases rapidly which may cause the saturation of the transformer core and cause severe inrush current. At the same time, the 500 kV transformer has a large capacity and the magnetizing inrush current decays slowly. This paper takes a 500 kV transformer which is newly built in Tongliang as an example, and a typical transformer UMEC model suitable for practical engineering is established. Through simulation and calculation of PSCAD/EMTDC, the effects of closing circuit breakers, capacitive voltage transformers, and transformer excitation characteristics on the inrush current are analyzed when the no-load 500 kV transformer is closed;meanwhile, measures are proposed to effectively suppress inrush current.
