Here, SPL, a China transformer factory, give you the reference about the oil immersed transportation protection. There 3 main safety protection devices:

1, gas relay: used for 800kVA and above oil-immersed transformer. When the contact capacity of gas relay is greater than 66VA or 15W and the gas accumulation is 250~300ml or within the range set in oil speed, the corresponding contact should be connected. The structure and installation position of the gas relay should be able to observe the amount and color of gas, and it is easy to take gas. Install it with a 1.5% increase in gradient. 220kV transformer oil tank cover should also have 1~1.5% increased slope.

2, pressure release valve: used for 800kVA and above transformers; When the pressure in the oil box of the safety airway or pressure relief valve reaches 5.07×104Pa, it should be released reliably. Two pressure relief valves should be set for the transformer with 120000kVA and above.

3, valve, vent plug: all transformer tank wall should be equipped with oil sample valve, 110kV, 90000kVA and 220kV, 63000kVA and above the middle of the tank wall should also have oil sample valve. 315kVA and above tanks shall have a drain device at the bottom. The lower part of the transformer tank should be large enough oil discharge valve, 220kV transformer should also have an accident oil discharge valve. The transformer must emit gas when filling oil and testing, so the upper part of the transformer pedestal, radiator, bushing, etc., is equipped with a vent plug to ensure the safety of the transformer.