Process Of A Transformer Explosion
Caused by aging (cumulation of moisture and suspended particles, creation of acids), the insulating oil loses the dielectric features.
This can lead to a sparkover, an electric arc is created. The arc vaporizes the insulating oil which has now, as gas, a considerable bigger volume: Shock waves are created. These shockwaves superimpose and lead to high static pressure – the tranformer housing is not able to compensate this pressure and bursts, the transformer explodes. From the first pressure peak to the explosion, it takes milliseconds only. Both, Buchholz Relay and pressure vent, react much too slow to prevent the transformer housing from bursting.
Process Of Transformer Protector TP
Transformer Protector TP is a passive, mechanical system and is put into operation by the first shockwafe – even before any static pressure can be generated.
Every TP model includes beyond others a bursting disc and a gas / oil collecting tank. In less than 2 milliseconds, the dynamic pressure peak activates the pressure reduction unit – oil and gas are led into separate containers. Contact of the high explosive gases hydrogen and acetylene and ambient air is excluded.
Surveys of the CEPEL Laboratory in Brazil and of Electricité de France have shown that the pressure inside a transformer has reached a noncritical level within three milliseconds after activation of the TP already.
By automatic or manual feeding of nitrogen into the tank and the instruments nearby, a safe environment for the quick repair of the transformer can be achieved.
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