Analysis of Non-Disassembly Diagnosis Technology for Leakage of Transformer Oil Pillow Capsules

The oil immersed transformer body is immersed in oil, and the entire body is in a sealed state filled with oil. Affected by temperature changes, the thermal expansion and contraction volume changes of transformer oil need to be buffered, and the decrease in oil caused by leakage needs to be supplemented. An oil pillow should be installed above the transformer body. The capsule communicates with the outside air through a respirator, and the internal air pressure is equal to atmospheric pressure. When the oil expands and contracts, the airbag contracts and expands, and the respirator exhales and inhales to maintain the balanced oil level inside the transformer. A new discovery in the inspection process of transformer oil pillow capsules has been summarized and analyzed in the domestic transformer capsule leakage inspection methods. Three effective oil pillow capsule leakage inspection methods have been summarized, including cotton swab bottom oil detection, static pressure holding test, and micro positive pressure holding gas inspection. The combination of these three methods can accurately diagnose whether the capsule leaks without dismantling and lifting it out, avoiding complex oil treatment on site and improving work efficiency.