Design and implementation of IEC 61850 in communication-assisted protection strategy

This paper presents a design and implementation of communication-assisted protection strategy to clear faults on a section of 115 kV transmission lines in Otter Tail Power system. The existing step-distance relaying scheme takes more than 25 cycles (417 ms) to clear faults on this particular three terminal line. In order to reliably clear all faults in less than 20 cycles (333 ms), the transmission line terminals communicate with each other through Ethernet to isolate and clear a fault as fast as possible. Through IEC 61850 Generic Object Oriented Substation Events (GOOSE) Messaging, the communication-based Permissive Overreaching Transfer Trip (POTT) scheme is utilized to achieve a faster and reliable clearance of all faults. The proposed method has been verified with ASPEN software and implemented in hardware.