Application of PLC in large transformer cooling system

The contact ants and relays is adopted in electrical control circuit of existed transformerpsilas forced-oil-air cooling control system, with low reliability, little protection function, uneasily extended and no communication interface. The way that programmable logical controller (PLC) with high reliability and versatility replaces partial unreliable contact ants and relays to modify older system is presented, and a new transformerpsilas forced-oil-air cooling control system is designed. Its site operation shows that the device is of high operation reliability and control accuracy, has perfect functions and notable effect of power saving.