KYN28A-12-type indoor metal-mounted switchgear (hereinafter referred to as switchgear) is a three-phase AC 50Hz indoor complete power distribution device, which is used to receive and distribute 3-12kV network power and to control, protect and monitor the circuit. Various types of microcomputer-based integrated relay protection devices can be installed on the panel of the relay cell of this product, and the intelligent control of the system can be realized. It has the functions of remote control, telemetry, remote signaling and remote adjustment, and controls the field network through the CAN bus with communication interface. It also has the functions of preventing misoperation of circuit breaker, preventing load push-pull handcart, preventing live closing of grounding switch, preventing power transmission of grounding switch at grounding position and preventing wrong entry into live interval, namely "five prevention" for short. The cabinet can be equipped with VS1 (I. e. ZN63), ZN12 V vacuum circuit breaker, can also be equipped with imported VD4 vacuum circuit breaker and VC series vacuum contactor.