POWER SYSTEM

A power system includes a photovoltaic cell panel, a first power conversion device converting the DC power from the photovoltaic cell panel into AC power, and outputting the AC power to an electric power grid, a DC-side switch device provided between the photovoltaic cell panel and the first power conversion device and opening upon a trouble, a storage battery, and a second power conversion device connected to a connection point between the photovoltaic cell panel and the DC-side switch device and controlling charging and discharging of the storage battery. The second power conversion device includes a normal charging control mode for charging the storage battery based on a command signal from the system host monitor. Disconnection charging control mode may be executed when the DC voltage of the connection point exceeds a predetermined threshold value even if the command signal does not instructs the normal charging control mode.