POWER SYSTEM LINKAGE

PROBLEM TO BE SOLVED: To provide a power system linkage that its private power generator system can continue running even if a fault happens in the commercial power system and the linked operation can be normally carried out during a maintenance period. SOLUTION: A first circuit breaker 1, a semiconductor switch 3, a reactor 5, and a disconnector 7 are connected in series to a power bus 105 that connects a commercial power system 101 and a private power generator system 103 having a private power generator facility, and further a second circuit breaker 9 is connected in parallel. When a fault happens in a normal operation, the semiconductor switch 3 instantly cuts off the circuit and the reactor 5 limits the fault current. During the maintenance, the first breaker 1 and the disconnector 7 are opened making the second breaker to maintain the linked operation. Thus the maintenance is carried out on the semiconductor switch.