CIRCUIT AND METHOD FOR PREVENTION OF OVERDISCHARGE

摘要

PROBLEM TO BE SOLVED: To provide an overdischarge prevention circuit that properly interrupts a complicated power line system at a substation and prevents overdischarging of a storage battery for a DC power supply unit installed at the substation. SOLUTION: The DC power supply unit 16 supplies DC power for driving a control system 27 of a power line system at a substation 2 by rectifying an alternating current from an AC input power supply. When there is not an AC input power supply, the power supply unit changes the power supply to a storage battery 23 to supply power. When the voltage of the storage battery 23 is reduced to a value immediately close to a discharge termination voltage or when a predetermined time (first predetermined time) passes after a state without the AC power supply is established, an extra-high vacuum circuit breaker 13 equipped in an extra-high system is caused to trip (turned off) using the remaining energy of the storage battery 23 immediately close to the discharge termination voltage. When a predetermined time (second predetermined time) passes after tripping of the extra-high vacuum circuit breaker 13, an air circuit breaker 24 on the output side of the storage battery 23 is opened using the remaining energy of the storage battery 23 immediately close to the discharge termination voltage. COPYRIGHT: (C)2011,JPO&INPIT