一般中小型工矿企业采用10KV供电,但动力和照明设备均为低压380V或220V的负荷,故采用变压器降压后再配电至各负荷。供电部门对用户电力系统的功率因数要求甚为严格,一般COSψ不低于0.9,低於该值就要受到罚款处理,因此功率因数补偿问题尤为重要。低压电网功率因数补偿的方法有2种,一种是手动方式;另一种是自动方式。所谓手动,就是通过手动操作按纽,控制交流接触器投切补偿电容,从而改变系统的功率因数。所谓自动,就是通过 General small and medium-sized industrial and mining enterprises with 10KV power supply, but the power and lighting equipment are low-voltage 380V or 220V load, so the use of transformer buck and then distribution to the load. The power supply department of the user power system is very strict power factor requirements, the general COSψ not less than 0.9, below which will be subject to fines, so the power factor compensation is particularly important. There are two methods for low-voltage power factor compensation, one is manual mode and the other is automatic mode. The so-called manual, that is, through the manual operation buttons, control AC contactor switching compensation capacitor, thereby changing the system’s power factor. The so-called automatic, is passed