Using GOOSE Messages in a Main–Tie–Main Scheme

Main–tie–main (MTM) transfer schemes increase reliability in a power system by switching a load bus to a secondary power source when power interruption occurs on the primary source. Traditionally, the large number of physical I/O lines required makes MTM schemes expensive to design and implement. Using Ethernet-based IEC 61850, these hardwired I/O lines can be removed and replaced with generic object-oriented substation event (GOOSE) messages. Adjustment of the scheme for optimal performance is done via software that saves redesign and rewiring times. Special attention is paid to change-of-state GOOSE only; no analog GOOSE messages are used, making the scheme fast and easy to configure, maintain, and troubleshoot. Applications such as fast motor-bus transfer are discussed with synchronization remaining at each breaker relay. Simulation test results recorded GOOSE message latencies on a system configured for an MTM scheme. This paper presents the details of open and closed manual and automatic transfers.