负荷电流对电接触点温升的影响

Influence of Load Current on Temperature Rise of Electrical Connector Contacts

由于高压电气设备的电接触点的发热功率和负荷电流的大小有关,在通过温度判断其是否存在电接触缺陷时需要考虑负荷的影响,因此文中研究了负荷电流对电接触点发热的影响。首先根据焦耳—楞次定律和热传递理论从理论上分析了电接触点的发热机理及温升规律,然后通过实验研究了隔离开关这种典型的电接触设备在负荷变化情况下发热部位的温度随时间的变化规律,以及发热部位稳态温升和负荷电流之间的关系。研究表明,对于隔离开关的触头和接线端,在负荷变化时其温度变化快慢和热时间常数有关,其稳态温升和负荷电流之间存在幂函数的关系。文中的研究结果为在不同负荷情况下判断电接触缺陷提供了参考。

The heating power of some electrical connector contacts of high-voltage equipment depends on load current,so the influence of load must be considered in fault diagnosis of the contacts via temperature. In this paper, the heating mechanism and the temperature change laws of the electrical connector contacts were analyzed theoretically with the Joule-Lenz’s law and the theory of heat transfer. Then experiments were conducted to obtain the temperature change of heating position of disconnector with time under varying load current and the relationship between steady-state temperature rise of the heating position and load current.Results show that the temperature change speeds of disconnector contact and terminal are related with thermal time constant,and the steady-state temperature rise has exponential function relationship with the load current.This study may provide reference for fault diagnosis of electrical connector contacts in different load conditions.