How to adjust the transformer output voltage?

The qualified rate of voltage standard is one of the main indexes to measure power quality. But due to a variety of reasons, the peak and trough period of electricity consumption is often very different, resulting in the distribution transformer output voltage up and down. The voltage fluctuation of the performance of various electrical equipment, production efficiency and product quality have different degrees of influence, therefore, in order to ensure the qualified rate of power supply voltage, timely adjustment of distribution transformer tap switch position is one of the solutions to the problem.

General distribution transformers mostly belong to no load voltage regulation, a total of three gears for adjustment. The number of turns of transformer winding can be changed by changing the position of moving contact of tap switch so as to change the output voltage. The common distribution transformer primary voltage is 10 kv, the secondary output voltage is 0.4 kV. The I position of the distribution transformer tap switch is 10.5 kV, the I position is 10 kV, and the switch position is 9.5 kV. Generally, it should be in the I position.

The specific steps to adjust the tap switch are as follows:

1. Power cut first. Disconnect the low-voltage side load of the distribution transformer, pull the high-voltage side drop fuse with insulation rod, and then take necessary safety measures. Open the tap switch protection cover on the transformer and place the locating pin in neutral position.

2. Adjust the gears, should according to the output voltage level, adjust the tap switch to the corresponding position, adjust the basic of tap-changer, principle is: when the transformer output voltage is lower than the allowable values, the tap-changer position from block to block I, I, or by the I block adjustment to the dish when the transformer output voltage is higher than the allowable values, the tap-changer position by properly block to block, I or I block adjustment to the I.

3. After adjusting the gear position, measure the DC resistance value of each phase winding with a DC bridge to check whether the DC resistance between each winding is balanced. If the resistance value difference between each phase is greater than 2%, it must be readjust, otherwise, after operation, static and static contacts will heat up or even discharge due to poor contact, and damage the transformer.