The protection of transformers using non electrical quantities such as oil, gas, and temperature is called non electrical quantity protection. There are mainly gas protection, pressure protection, temperature protection, oil level protection, and cooler full stop. Protective relays and devices have been developed over 100 years ago to provide “lastline”of defense for the electrical systems. They are intended to quickly identify a fault and isolate it so the balance of the system continue to run under normal conditions. The selection and applications of. Relion protection and control relays for several application reduce complexity. The relays are in round glass cases.