大型发电机中性点采用高阻抗配电变压器接地的配置方法

Configuration of Large Generator Neutral Grounding Through High Impedance Distribution Transformer

大型发电机定子绕组对地电容较大,发生定子单相接地故障时电容电流也较大,采用中性点经配电变压器接地方式,能起到对过大故障电流限制的作用。采用高阻抗变压器作为中性点接地变压器的配置方法,利用变压器内在电抗生成的电感性电流,对故障电容电流进行部分补偿,在满足抑制故障暂态过电压要求的同时,将接地故障电流限制在允许范围内,解决了配置大型发电机中性点接地装置中常见的接地故障电流过大问题。

The excessive fault current induced by stator single-phase earth fault and big ground capacitance of stator winding of large generator can be restricted by neutral grounding through distribution transformer. This paper intro- duces a configuration method of generator neutral grounding device with high impedance distribution transformer. The fault capacitive current is partly compensated by the inductive current generated from the internal reactance of the transformer, and the ground-fault current is limited within an allowable range while the fault transient overvolt- age is restrained.