Protection device for oil-immersed transformer

Oil-immersed transformers are also widely used in daily life, and they are an important electrical facility and equipment. Oil-immersed transformers are manufactured with some protective devices for safe use. So what are the protection devices of oil-immersed transformers?

Safety protection device

1. Gas relay

Used for oil-immersed transformers of 800kVA and above.

2. Pressure relief valve

Used for transformers of 800kVA and above.

3. Valves, valves, bleed plugs

The lower part of the tank wall of all transformers should be equipped with an oil sample valve, and the middle part of the oil tank wall of 110kV, 90000kVA and 220kV, 63000kVA and above should also have an oil sample valve.

Oil protection device

1. Oil conservator and oil level gauge.

Oil-immersed transformers should be equipped with oil conservator (except for sealed type). The volume of the oil conservator should ensure that the transformer oil does not overflow when the ambient temperature is +40°C under full load, and the oil level should be visible when the oil level gauge is not put into operation at -30°C. The oil level gauge at one end of the oil conservator should have three oil level signs with oil temperature of -30℃, +20℃, and +40℃. The oil conservator should have oil filling, oil drain, and sewage drainage devices. Below 8000kVA is a general type oil conservator, and 8000kVA and above are a diaphragm type or capsule type oil conservator.

2. Moisture absorber.

Used for non-sealed oil-immersed transformers of 100kVA and above.

3. Oil purifier.

Used for oil-immersed transformers of 3150kVA and above.

4. Anti-oil aging device.

It is used for transformers of 8000kVA and above; the measures to prevent oil aging are measures to ensure that the transformer oil does not come into contact with the air.

Oil temperature measuring device.

1. Glass thermometer.

Used in all transformers. The transformer should have a tube socket for a glass thermometer. The tube socket is set on the top of the oil tank and extends 120±10mm into the oil. When the centralized cooling structure is adopted, a glass thermometer tube holder is also installed near the main pipe of the oil tank inlet and outlet.

2. Signal thermometer.

Used for transformers of 1000kVA and above. The contact capacity of outdoor signal thermometer is greater than 50VA or greater than 15W. The installation position of the signal thermometer should be easy to observe. The strong oil circulating transformer should be equipped with 2 signal thermometers.

3. Remote temperature measuring element.

Used for transformers of 8000kVA and above. The strong oil circulating transformer should have 2 remote temperature measuring elements, such as resistance temperature measuring elements, and they should be placed at both ends of the long shaft of the oil tank.