A protection control apparatus includes a computer, communication controller, and shutdown circuitry. The computer monitors fail signals delivered from the power conversion circuitry to a first number of first signal lines, and creates reject information indicating whether each fail signal is enabled or rejected. The communication controller receives the reject information from the computer via a second number, which is smaller than the first number, of communication lines, and delivers reject signals to the first number of second signal lines, based on the reject information. The shutdown circuitry is provided on the same chip or module as the communication controller, and permits driving of the power conversion circuitry or shut down the power conversion circuitry, based on the fail signals from the first number of first signal lines, and the reject signals from the first number of second signal lines.