A generic communications language-four years of experience

The introduction of the microprocessor to protective relays and other technological advances have made it feasible to add communication facilities to relays, enabling remote monitoring by direct extraction of available data and remote control of the items of plant connected to the relays. Power utilities have shown a marked change in attitude by an ever increasing interest in using relay communication features. Principally to remove the need for external monitoring and control devices, such as transducers and auxiliary relays, thus reducing functional duplication, wiring, commissioning and hence lowering cost. As yet there is no accepted international standard for communication links with protective relays. Work within the IEC has resulted in the proposal, IEC870-5 companion standard 103, as the informative interface for protection and control relays. This proposed standard embodies the generic principles developed and used within our generic protocol. This paper describes a generic communication system developed specifically for remote monitoring and control of protective relays within the substation environment, changes in attitude towards communications, practical experience and it´s influence on IEC870-5-103