Gas relay protection for transformers
When there is fault happened to oil immersed transformers, arc generated by short circuit current will decompose transformer oil and insulation materials, therefore, a large amount of gas will generated, which will flow from oil tank to oil conservator. The protection to response for gas flow and oil flow is gas protection. The main gas protection element is gas relay. After setting of relay, install it on the crossover pipe of oil tank and oil conservator and the arrow on the gay rely should point to oil conservator side.
As gas relay protection wiring schematic diagram shows, the upper contact of gas relay 1 is light gas relay protection, which will send delay signal after action. Lower contact of gay relay is heavy relay protection, which will start outlet medium relay 3 through signal relay 2 after action to trip CB at two sides of transformer. To prevent misaction when change oil or do test on gas relay, connect heavy gas circuit to signal circuit by connecting plate.