低压系统短路电流计算和断路器整定

Calculation of Current in Short-Circuit and Setting of Circuit Breaker for Low Voltage System

短路故障是电气故障中最常见、危害最大的一类,短路电流计算是低压配电系统设计的重要环节之一。石油化工工程项目设计中,用电设备特别是电动机的功率都较大,发生短路时,往往需要考虑电动机反馈电流的影响。因此,短路电流的计算及断路器的整定变得较为复杂。本文拟在通过对低压系统短路电流的计算以及结合工程项目实例,说明存在大功率异步电动机的低压系统中断路器的选择整定及校验方法。

Short circuit fault is the most common and harmful electrical fault.The short-circuit current calculation is an import part of the low voltage distribution system design.In petrochemical engineering project design,the power of electric equipment,especially motor,is very high.When short circuit occurs,the influence of motor feedback current should be considered.Therefore,the calculation of short circuit current and the setting of circuit breaker become more complicated.This paper explains the setting and calibration method of circuit breaker in low voltage system with high power asynchronous motor by the calculation of low-voltage system short-circuit current and combined with the engineering project example.