The body and other device assembly of the transformer

lower box

Before the body is unboxed, a comprehensive inspection of the body should be carried out. The body should be clean, free of dust, grease, dirt, paper strips and tapes and other debris, and the insulation of all parts of the iron core, such as clip insulation, foot insulation and side screw insulation, should be good. All fasteners, especially the fasteners of the lead bracket, should be tightened again, and the winding spacer should not be loose. Check the insulation distance between the leads and the windings, the fuel tank, the clamps and the leads again, as shown in Figure 1.

The body and other device assembly of the transformer
Figure 1 – Body assembly of distribution transformer

Check that the fuel tank should be clean and free of debris. After the comprehensive inspection, use qualified transformer oil to fully flush the body. When the lifter body is unloaded from the box, the body of the lifter should be kept stable, and there should be personnel around to support it, and the lead wires should not be damaged. The positioning pin should be inserted into the center hole of the iron core foot exactly. Tighten the box lip bolts so that the box cover is slightly raised. If the box cover sags, adjust the lower screw to meet the slightly raised requirements.

Assemble radiator, oil purifier and signal thermometer

(1) For the detachable air-cooled radiator and forced oil circulation air cooler, first close all the butterfly valves, and then remove the temporary closing plate on the connecting flange. Lift the radiator by a crane and put a rubber apron on it, adjust the positioning of the flanges of the upper and lower connecting pipes respectively, and tighten the bolts.

Install all overhauled fans. The connecting cable should use a plastic cable with good oil resistance and wear it in a metal snakeskin hose. The cables are fastened to small brackets welded to the fuel tank with clips. After the wiring is completed, measure the insulation resistance with a 500V insulation resistance meter, the value should not be lower than 0.5MΩ, and the fan should be energized and run for 1 hour. If there is noise, vibration and friction during operation, it must be adjusted.

The strong chasing oil circulating air cooler should also be equipped with a submersible oil pump, a cooler and a control box, and each cooler group should be marked with a prominent number with paint.

(2) Assemble the oil purifier. Before assembly, put the dry adsorbent silica gel into the can, and sieve the silica gel to remove impurities, dust and debris before filling the can. After installation, open the connecting butterfly valve to put the oil in, and at the same time unscrew the upper vent plug to discharge the air. When the oil flows out and the air is exhausted, tighten the vent plug and close the connecting valve.

(3) Assemble the signal thermometer. The indicator head of the signal thermometer is installed on the side of the transformer tank, which is convenient for operators to observe. The temperature measuring tube is installed on the top cover of the fuel tank together with the mercury thermometer. The pointer of the meter head is set according to the fixed value proposed by the design or operation department. For example, the fan of the air-cooled transformer stops at 45°C, the fan starts at 55°C, and an alarm signal is issued at 85°C. In order to protect the meter head, a rain cover should also be installed.