Remote automatic signalling system

The Northern Ireland Electricity (NIE) rural 11 kV distribution system is controlled by switchgear with automatic tripping and reclosing facilities operated by protection relays. This equipment is located either at 33/11 kV substations as circuit breakers or on overhead lines as ACR´s and sectionalisers. In Craigavon area a network of 500 km of 11 kV overhead line is fed from 40 substations with 200 OCB´s, 50 ACR´s and 100 sectionalisers. On the NIE system, when a permanent fault occurs and automatic equipment opens or fuses blow, they rely completely on phone calls made by customers off supply, and subsequent analysis of these calls to ascertain the extent of the fault before assigning an engineer. During storm conditions this analysis can be very difficult and often there are delays because of the very large number of calls requiring sorting. After trying various methods the authors produce a system based on a telephone-linked burglar alarm system-the Scantronic Digital Communicator linked to various relays to analyse the performance of the various switchgear