Central testing and site commissioning for a new, user programmed, 33 kV feeder protection

A new user programmed feeder protection relay is being applied to overhead power lines in Manweb´s rural 33 kV network. The relays are complex and multifunctional. They utilise low grade variable frequency pilots and perform full unit protection, switch-onto-fault and single-end-fed tripping, voltage compensated back up protection, autoreclose, alarm and trip data logger , and indicating meters. The microprocessor protection relay for overhead line protection, MPR (OLP), was a joint development. Manweb sponsored the research and wrote the application software and GEC ALSTHOM developed hardware and operating system software. The authors set out the main methods that were used, describe the experience obtained and conclude that the programme is a success