Implementation of adaptive dispersed phase current differential protection for transmission lines

This paper proposes the adaptive current differential principle combining instantaneous value with fault component instantaneous value for dispersed phase current differential protection. The adaptive synchno-adjusting method adopts synchronized sampling based on GPS clock as the main way and sampling-interval adjustment sampling-data correction as an auxiliary way, and the adaptive telecommunication mode matching in special/compound channel. According to the operating and fault status of the power system and telecommunication equipment, the adaptive protection can change in time its restraining characteristic, synchronization principle and remote communication mode. Meanwhile, the protection hardware system which possesses opening ability, being an all-purpose platform for all kinds of digital protection, has been developed. Under various operating and fault conditions, the protection device is extensively tested using the dynamic simulating model. It has been proved that the protection device has excellent performance and is very suitable for all types of transmission lines.