Typically, one end of the transformer oil pillow is equipped with an oil level gauge with three oil level lines (or temperature indication lines) indicating oil temperatures of -30 ° C, + 20 ° C and + 40 ° C to monitor oil levels at different oil temperatures High and low. According to the three oil level line can determine whether the need for oil or oil. If the temperature is +20 ℃, the oil level is higher than +20 ℃ this bit line, then the oil in the transformer, and should inform the maintenance personnel to put oil, so that the oil level down to the oil level line; in the same oil Temperature, if the oil level below +20 ℃ this bit line, then the oil in the transformer less, should inform the maintenance personnel to refuel. If a large number of oil spills, the oil level is rapidly reduced, as low as the gas relay below or continue to decline, you should immediately disable the transformer.