大容量发电机主变压器感应过电压计算

当冲击电压波侵入到变压器高压绕组时,除在本绕组内产生暂态振荡外,也会通过静电和电磁感应传递到低压绕组中,使低压绕组侧产生过电压。本文以主变压器高压侧避雷器的残压为冲击电压限值,对主变压器低压侧和发电机出口可能的过电压,以及发电机出口冲击电压上升速度进行近似计算,并以此为依据选择避雷器和电容器。

Calculating Induced Over Voltage for Main Transformers in Large-capacity Generators

When an overvoltage disturbance intrude into the high-voltage windings of a power transformer,transient oscillations of the current and voltage will occur in the high-voltage side,and related oscillations will also occur in the low-voltage side through electrostatic and electromagnetic induction between the windings,which usually brings overvoltage in the low-voltage windings.In this paper,the residual voltage of the high-voltage arresters is used as a limit overvoltage.This paper provides a proximate calculation model of the overvoltage in the low-voltage windings and the generator outlet.The maximum and rising velocity of the overvoltage is calculated according to this model.Appropriate arresters and capacitors are recommended based on the calculating results.