POWER SUPPLY SYSTEM INCLUDING ELECTRICAL EQUIPMENT

PROBLEM TO BE SOLVED: To provide a power supply system capable of causing electrical equipment to recognize power failure using no communication line from an emergency power supply unit.SOLUTION: An emergency power supply unit 3 includes: a storage battery 2; a power converter 5 that converts the power from the storage battery 2 into an AC power; frequency detecting means 10 that detects the frequency of a commercial power supply 1; and power control means 12 that controls the power converter 5 by detecting the power failure based on the frequency. Electrical equipment 4 includes: frequency determination means 13 that determines the frequency of the supplied power; a storage 14 that stores the frequency; and equipment control means 15 that compares the frequency to the frequency stored in the supply power to control the electrical equipment 4 to operate and stop. Detecting a power failure, the power control means 12 supplies the power of a frequency from the power converter 5, the frequency of which is different from that from the commercial power supply 1. When the frequency is different from that from the storage 14, the equipment control means 15 recognizes an occurrence of a power failure and controls the power consumption of the load to the minimum. Thus, a power supply system including electrical equipment requiring no communication wire is achieved.