How to Overhaul a Transformer Conservator (Oil Pillow)?

Overhaul Items for Transformer Conservator:

1. Ordinary-Type Conservator

• Remove the end covers on both sides of the conservator, clean rust and oil deposits from inner and outer surfaces, then apply insulating varnish to the inner wall and paint to the outer wall;

• Clean components such as the dirt collector, oil level gauge, and oil plug;

• Check that the connecting pipe between the explosion-proof device and the conservator is unobstructed;

• Replace all sealing gaskets to ensure good sealing with no leakage; withstand a pressure of 0.05 MPa (0.5 kg/cm²) without leakage;

• Check that the Buchholz relay connecting pipe extends into the conservator and protrudes 20 mm above the bottom surface;

• Check that the glass of the oil level gauge is intact, clean, and transparent; the temperature indication lines should be clear—if not, re-mark them.

2. Capsule-Type Conservator

The overhaul procedure for a capsule-type conservator is basically the same as that for an ordinary conservator. The installation procedure is as follows:

• Check the capsule’s sealing performance by conducting a pressure test: at a pressure of 0.02 MPa (0.2–0.3 kg/cm²), there should be no leakage for 72 hours; alternatively, submerge it in a water tank and check for absence of air bubbles;

• Secure the capsule to the hook using a nylon rope, connect the outlet properly, and reinstall it onto the manhole flange. To prevent oil from entering the capsule, the capsule outlet pipe must be positioned higher than the oil level gauge and explosion-proof device outlets, and all three should be interconnected.

3. Diaphragm-Type Conservator

• Prior to disassembly and overhaul, perform a sealing test by filling with oil: the diaphragm should withstand a pressure of 0.02–0.04 MPa (0.2–0.3 kg/cm²) without leakage for no less than 72 hours;

• Disconnect all connecting pipes, remove the middle flange bolts, take off the upper section of the conservator tank, and remove the diaphragm;

• Other overhaul procedures are basically the same as those for an ordinary conservator;

• Reassemble the conservator in the reverse order of disassembly.