Abstract
At DC railway substations high-voltage DC ground fault relay (hereafter referred to as a 64P relay) are currently used to detect DC ground faults within the substation. When a ground fault occurs at the substations, the 64P relay send a command immediately to open all related circuit breakers. However, some ground faults can cause damage to surrounding facilities as well as the point of the accident. At the same time, they could also possibly hamper ground fault protection due to contact faults with auxiliary energizing source. We have therefore conducted development of a ground fault relay that needs no auxiliary energizing source (DC110V) to achieve a protection system where power supply is stopped without fail in case of ground faults. We have thus-far finished production of a prototype and confirmed that the target performance has been met.
