Power conversion system

A power conversion system, comprising:

• a power converter configured to convert direct-current power input from a direct-current power supply, into alternating-current power or direct-current power;
• a capacitor provided between a positive electrode direct-current line and a negative electrode direct-current line connected to input terminals of the power converter;
• a ground line provided with a first ground resistor and configured to connect the negative electrode direct-current line and a ground potential;
• a ground switch provided in the ground line on grounding potential side of the first ground resistor;
• a discharge line configured to connect the positive electrode direct-current line and the ground line on the ground potential side of the first ground resistor;
• a discharge switch provided in the discharge line and configured to be turned on to discharge residual charges of the capacitor;
• a first disconnection switch provided in each of the positive electrode direct-current line and the negative electrode direct-current line, and configured to be turned off to disconnect the direct-current power supply from the power converter;
• a second disconnection switch provided in an output line from the power converter to a power system, and configured to be turned off to disconnect the power system from the power converter;
• and
• a control apparatus configured to control ON or OFF of each of the discharge switch, the first disconnection switches, and the second disconnection switch, the control apparatus being configured to turn on the discharge switch after turning off the first disconnection switches and the second disconnection switch.