epoxy resin bushing

The epoxy resin bushing of a transformer is the core insulation component that connects the high-voltage side of the transformer to the external power grid. Its main function is to achieve the "conduction" function of the transformer winding lead wire, while isolating the high-voltage charged body from the transformer oil tank (grounding terminal), preventing leakage or breakdown, and is a key component to ensure the safe and stable operation of the transformer. Its performance directly affects the insulation level, temperature resistance, and service life of transformers, and requires a deep understanding from the dimensions of structure, characteristics, type, faults, and maintenance:

1、 Core function: Dual function of "conductivity+insulation"

When the transformer is in operation, the winding lead wire needs to be led out from the sealed oil tank to the outside (such as connecting overhead lines and cables), but there are two core contradictions in the lead out position:

High voltage insulation contradiction: The outgoing line carries high voltage (such as 110kV, 220kV), while the oil tank is grounded at a low potential. If it comes into direct contact, it will cause "ground breakdown";

Sealing and moisture-proof contradiction: The fuel tank is filled with insulating oil, which needs to prevent oil leakage and prevent external moisture and dust from entering the tank and damaging the insulation.

Epoxy resin sleeves are designed to solve these two contradictions, and their core functions can be broken down into three points:

Insulation isolation: Through the high insulation performance of epoxy resin, it blocks the current path between high-voltage lead wires and the oil tank (grounding terminal), withstands rated voltage and short-term overvoltage (such as lightning overvoltage), and prevents breakdown;

Conductive lead out: A "conductive rod" (usually made of copper) is embedded inside the sleeve, with one end connected to the transformer winding lead out and the other end connected to the external power grid to achieve current transmission;

Sealing and moisture-proof: The joint between the sleeve and the fuel tank adopts a sealing structure (such as O-ring, sealant) to prevent insulation oil leakage inside the fuel tank, while blocking external water vapor and impurities from entering, protecting the insulation environment inside the fuel tank.