Pilot Wire Relay Applications in Industrial Plants Utilizing a New Static Pilot Wire Relay

Pilot wire relaying is an extremely effective way to provide fast, selective protection for industrial plant cable tie circuits. The operating principles of popular pilot wire relay schemes will be reviewed, and special attention will be given to a new static pilot wire relay which offers an improvement in ground fault sensitivity, an especially significant consideration on resistance grounded industrial systems. A discussion of pilot wire overvoltages and overvoltage protective devices is also presented.