The pt secondary loop voltage drop is a changing amount and has the characteristics of indirection and certain randomness . the second , according to the cause of pt secondary loop voltage drop , the different methods to reduce the pt secondary loop voltage drop were analyzed and the conclusions are draw as below : 1 . changing bigger section wire and maintaining the connector plugs regularly can reduce the pt secondary loop voltage drop effectively , but ca n ' t guarantee which meets the relevant rules 首先，通过对电压互感器二次压降的形成机理进行分析，得出以下关于二次压降的相关结论： 1 、电压互感器二次压降等于二次回路阻抗和回路电流的乘积； 2 、电压互感器二次回路阻抗分为元器件自身阻抗和接触阻抗两部分，且接触阻抗占主要部分，从而使得电压互感器二次回路阻抗具有动态特性，而且具有一定的随机性； 3 、电压互感器二次回路电流与二次负荷和回路阻抗大小相关，因而二次回路电流也是变化的； 4 、电压互感器二次压降是一个变化量，且具有单向性和一定的随机性。
