POWER MANAGEMENT SYSTEM

A town storage battery power conversion device outputs an AC voltage to a distribution system during a power failure. Electric power generated by a solar cell installed in each consumer house is converted into an AC voltage by a solar cell power conversion device and output to a consumer premises distribution system to which a load is connected. In an autonomous operation during a power failure, an operation plan for a distributed power supply is updated in a cycle longer than a cycle of an operation plan for a town storage battery. In the autonomous operation, the town storage battery power conversion device changes an AC voltage frequency according to a difference between electric power output from the town storage battery and the operation plan. The solar cell power conversion device has a function of modifying a control target value for the solar cell according to the AC voltage frequency.