The gas detector relay is a protective device that gives an early indication of faults occurring in oil filled conservator type power transformers. These faults fall into two general classes:
(1) Faults of an incipient or minor nature resulting in a slow evolution of gas. This gas may be generated by local heating, defective insulating structures, improperly brazed joints, loose contacts, grounds, short circuit turns, burning of core steel, or from air in the transformer.
(2) Faults of a major nature that generates a sudden pressure wave. Major faults are usually caused by flashover between parts.
The relay will detect either of these classes of faults. Test sample of accumulated gas available.