位移电压法的改进与仿真分析

Abstract

位移电压法是间接测量对地电容方法中的一种,但该方法在计算对地电容时,个别结果会出现较大误差.针对这一问题,本文提出了先估算谐振点电感值L,然后以2倍的L值与2.5倍的L值分别调节电感,再使用位移电压法计算对地电容的方法.并利用Matlab仿真平台,建立了中性点经消弧线圈接地的电网模型.在此模型基础上,对改进前后的位移电压法进行了仿真比较.实验结果表明,使用改进后的位移电压法计算出的对地电容更为准确,误差小于1%.

Displacement voltage method was one of the ways of measuring capacitor of system grounding indirectly,but there were some results having a large error.In view of the problem,this paper proposed a new method.Firstly,the inductive reactance(L) on the resonance point was estimated.Then,the arc suppression coil was adjusted with 2 times of L and 2.5 times of L.Lastly,the capacitor of system grounding was calculated by using displacement voltage method.Moreover,the model of resonant earthed system was established with the graphics simulating software Matlab.Based on the model,a comparison was performed between former and improved displacement voltage method.The results indicated the improved displacement voltage method was more accurate and the error was less than 1%.