考虑负序电流效应的异步电动机过负荷保护

Induction motor overload protection accounted for the negative sequence current effect

本文简述了常规保护装置的过负荷保护原理及其存在的缺点。基于表征物体发热过程的第一热定律 ,推导了异步电动机的热模拟方程 ,在推导过程中 ,考虑了电动机转子条的集肤效应、负序电流效应 ,导出了负序电流效应系数 K′的计算公式。微机保护装置以该模拟方程为动作方程 。

The conventional induction motor overload protection and its imperfections are introduced The paper derives induction motor's thermal simulation equation based on the First Thermotheorem that responds to matter heating process In the process of deriving, the Skin Effect in the rotor bars and the negative sequence current effect are considered,and the equation of the negative sequence current effect constant K' is derived The microprocessor-based protection device can realize good overload protection for using the thermal simulation equation as the operation equation