Power supply system and switch unit

A power supply system, comprising:

• a control unit;
• a switch;
• a direct current source;
• and
• a power change unit, wherein the switch is electrically connected between the direct current source and the power change unit, the control unit is configured to send a switch-off signal to the switch when the direct current source or the power change unit is faulty, the switch comprises a switch unit and an operation mechanism, the operation mechanism is configured to receive the switch-off signal and control the switch unit to be turned on or off, and the switch unit comprises:
• a first static contact;
• a movable contact, having a rotation center, wherein the movable contact is configured to rotate about the rotation center relative to the first static contact, the movable contact is configured to connect to or disconnect from the first static contact, and when the switch unit is turned off, the movable contact rotates about the rotation center relative to the first static contact by a first included angle to be separated from the first static contact, to generate a first arc;
• a first arc extinguishing structure, located around the first static contact, and configured to extinguish the first arc, wherein the first arc extinguishing structure comprises a first arc extinguishing end part and a second arc extinguishing end part, a connection line between the first arc extinguishing end part and the rotation center of the movable contact is a first line, a connection line between the second arc extinguishing end part and the rotation center of the movable contact is a second line, an included angle between the first line and the second line is a second included angle, and an angle value of the second included angle is greater than or equal to an angle value of the first included angle.