Moebius-Strip for High Voltage AC Switchyards of High Availability

High Voltage ac switchyards are core elements of any High Voltage ac grid and should be permanently available at reasonable costs. Existent switchyard designs such as ring- or breaker-and-a-half-structures try to fulfill these requirements. Another scheme – the crossed-ring arrangement – is to be counted into this category too. It also needs 1½ circuit-breakers per feeder and has the physical appearance of a closed strip. By twisting this strip into a Moebius-strip the availability of the feeders of such a High Voltage ac switchyard is further increased. This is demonstrated by comparing the three switchyard types of Moebius-strip, crossed-ring and breaker-and-a-half, based on non-available feeders and non-available circuit breakers respectively. The Moebius-strip arrangement clearly provides the best feeder availability, followed by the crossed-ring – and at a great distance - the breaker-and-a-half arrangement. Therefore, it might be a solution for central grid nodes and strategically important High Voltage ac substations.