WIRELESS SELECTIVE TRIPPING OF AC POWER SYSTEMS CONNECTED IN PARALLEL

摘要

A parallel redundant power supply system (10) which does not use any inter-unit signalling is obtained by deriving all information necessary from the output signals of each respective power system (10). Each respective power system (10) monitors its own power output, rather than comparing itself to other units. The trip function is created by sampling the AC output voltage of the power system (10) and multiplying an instantaneous difference in voltage (compared with a previous cycle) with the instantaneous difference in current (compared with a previous cycle) of the power system's (10) AC output power. If the two transients are in opposite directions, then the multiplicative product will be negative, indicative of a good power system (10). If the two transients are in the same direction, then the multiplicative product will be positive, indicative of a failed unit. The power system (10) is removed from the power circuit when the multiplicative product is positive and greater than a predetermined trip value.