A frequency detector detects a system frequency from an AC voltage on an AC power line to which a power conditioner performing system interconnection of a distributed power supply is connected. A power converter is configured to inject lead reactive power ...

An uninterruptible power supply device has a normal mode of supplying a load with electric power supplied from an AC power supply, a backup mode of supplying the load with electric power stored in a storage battery during a power failure, and a deteriorati...