Transformer pressure relief valve details

Date: June 24, 2025 17:07:04

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  • Securing the fuel tank: When the transformer internal failure, such as coil short circuit, iron core overheating, etc., oil decomposition will produce a large amount of gas, so that the pressure in the tank rises sharply.pressure relief valveCan be opened in time, discharge part of the transformer oil and gas, reduce the pressure in the tank to prevent the tank deformation or cracking1The
  • Maintain tank seal: After the pressure is lowered, the pressure release valve will automatically close to keep the tank sealed, effectively preventing external air, moisture and other impurities from entering the tank and avoiding problems such as moisture and aging of the transformer's internal insulation.

Working Principle1

  • The opening process: The pressure relief valve is bolted to the upper part of the transformer tank, with two springs inside exerting pressure on the membrane disk, which is sealed by a sealing ring. When a large amount of gas is generated by the internal failure of the transformer, the pressure of insulating oil on the membrane disk is greater than the spring pressure and reaches the opening pressure, the membrane disk rises rapidly and detaches from the rubber ring, the transformer oil is discharged through the oil injection port, the pressure release valve opens rapidly within 2ms, and the internal pressure of the transformer is reduced rapidly.
  • Closure processWhen the pressure in the tank drops to the closing pressure value of the pressure relief valve, the diaphragm disk resets under the action of the spring, and the valve closes, stopping the discharge of oil and keeping the positive pressure in the tank.

Structure Composition

It mainly consists of spring, signal rod, junction box, rubber pad, pressure diaphragm disk, oil injection port, micro switch and other parts. Among them, the spring is used to provide pressure to keep the membrane disk closed under normal conditions; the signal lever and microswitch are used to send out action signals; the rubber gasket and the pressure membrane disk ensure the sealing performance; and the oil injection port is the channel for discharging transformer oil and gas when the valve is open.

Installation and Selection

  • mounting position: Usually installed around the top cover of the transformer, as close as possible to the ends of the tank, can be in any position between above the core and right above the windings, the pressure relief valve for large transformers is generally installed at both ends of the transformer to ensure that the pressure relief valve can effectively drain the oil after work1The
  • Selection parametersIncluding shell type, opening pressure, wiring, color, sealing gasket material, signal marker, etc., need to be based on the transformer's capacity, voltage level, operating environment and other factors for a reasonable choice4The

Maintenance and Inspection

  • Maintenance Points: Regularly check the appearance of the pressure relief valve for damage, oil leakage, etc.; check whether the signaling lever is properly reset; clean the valve port and surrounding oil and impurities to ensure smooth valve operation.
  • Testing ProgramAccording to JB/T 7065-2004 standard, there are opening pressure test, opening time test, signal contact insulation performance test, aging opening performance test, sealing pressure value of the sealing performance test, etc.4The