ELECTRIC POWER CONTROLLER

PROBLEM TO BE SOLVED: To provide an electric power controller that only when conditions for allowing for autonomous operation are reliably satisfied, can perform the autonomous operation so as to supply an AC power to a power load connected to a power system before the autonomous operation.SOLUTION: When receiving an instruction to be changed so as to be autonomously operated, the electric power controller connects an inverter 21 to loads 6a, 6b and 6c through a parallel-off relay 24 to start autonomous operation if voltage applied to a wiring part between the parallel-off relay 24 and an electric leakage breaker 25 is not detected, current flowing between a master breaker 42 and a power system 5 is not detected and a contact signal for signaling the switching condition of the master breaker 42 signals that the breaker 42 is open. When the controller is in a position of the autonomous operation and the current flowing between the master breaker 42 and the power system 5 is detected or the contact signal for signaling the switching condition of the master breaker 42 signals that the breaker is closed, the inverter 21 becomes parallel off from the power system 5 through the parallel-off relay 24 to stop the autonomous operation.