Action Analysis of Main Variable Weight Gas Gaused by an Out-of-Area Fault

Heavy gas protection of the main transformer is used as the non-electric main protection of the main transformer. After a serious fault occurs inside the main transformer, the oil flow of the main transformer will impact the baffle plate of the gas relay, and the heavy gas device will act quickly and jump off the switches on each side of the transformer to protect the transformer [1]. This paper analyzes an event of the main transformer heavy gas protection maloperation caused by the fault crossing current outside the 35 kV transformer area, and analyzes the cause as the fault outside the main transformer heavy gas area, and the operation value of the main transformer heavy gas is less than the requirements of the regulations. The reliability of the heavy gas action is effectively improved by adjusting the action setting measures of the heavy gas relay in the main transformer according to the requirements of the regulations. To ensure proper operation of heavy gas protection.