In the 0.4kV low voltage 3-phase 4-wire distribution network, the load is mostly single-phase load.The distribution network designed according to the average number of households has serious unbalance due to the difference of electricity consumption in different periods.

The main harm of 3-phase load unbalance problem:

1.1. The neutral line current is very large, leading to the line voltage drop is large, loss increase, and accelerated aging line.

1.2.The heat of the electrical transformer is serious, easy to cause fire, and affecting the safe operation of the equipment.

1.3.The neutral point deviation, resulting in the power supply voltage is not stable, the voltage unqualified rate increases.

1.4. Single phase overload leads to large area power failure and high complaint rate.

Adopt manual phase adjustment is time-consuming, laborious, timeliness, poor pertinence, and can not effectively solve the problem.Source prevention, normal monitoring, scientific policy and dynamic management are the basic principles of operation and maintenance work. The long-term goal of operation and maintenance work is to establish the normal monitoring and dynamic adjustment management mechanism of 3-phase load in the electrical transformer distribution district, effectively improve the power supply quality , reduce the loss and enhance the safe and economic operation level in the transformer distribution district.

ETCR5500 Phase-changing Switch Type 3-phase Unbalance Correction Device is a real-time and intelligent automatic load control system independently research and developed by ETCR Technology, which can orderly phase-changing control for single-phase load access, and can effectively correction the 3-phase unbalance problem in the electrical transformer district.The device has been running well for several years in the transformer district installed in the China State Grid and South Grid, and the treatment effect is remarkable