Patent ID: 7869167

Claim:
A system to prevent fire and/or explosion in an electrical transformer ( 30 ) or to protect the transformer ( 30 ) from resulting fire and/or explosion in advance before decomposition of combustible coolant fluid ( 11 ) or dielectric oil, said system comprising: one or more differential current sensing electrical relays ( 26 ) for calculating the difference of an input current and an output current with a predetermined limit and thereby providing first input to one or more control units ( 1 ), if a ratio of input current to output current exceeds more than the predetermined limit; wherein said input current and output current are the currents from a high voltage conductor ( 22 ) and a low voltage conductor ( 23 ) of the electrical transformer ( 30 ) respectively; one or more Buchholz relays ( 18 ) for sensing excessive oil surge in the transformer ( 30 ) and thereby providing second input to the one or more control units ( 1 ), one or more circuit breakers ( 24 , 28 ) for obtaining input signals from the one or more differential current sensing electrical relay ( 26 ) and Buchholz relays ( 18 ) and thereby providing a third input signal to the one or more control units ( 1 ), and wherein the one or more control units ( 1 ) for receiving first, second and third input signals from the said one or more differential current sensing electrical relays ( 26 ), one or more Buchholz relays ( 18 ) and one or more circuit breakers ( 24 , 28 ) respectively, and thereby generating a control signal to energize a lifting magnet ( 5 ) for draining of the combustible coolant fluid ( 11 ) through a drain valve ( 4 ) and subsequently injecting inert gas from the bottom of an electrical transformer tank ( 14 ) through a nitrogen release valve ( 6 ) for stirring the combustible coolant fluid ( 11 ) and bringing down temperature and oxygen content for preventative and/or protective measures against the explosion and/or resulting fire in the electrical transformer ( 30 ).