KYN28A-12 is fully known as indoor metalclad enclosed switchgear, which is divided into three layers of structure,it can be used as a power supply equipment, and it can also be used as the two power distribution equipment. According to the type of switch device, there are two kinds of floor type and middle type. The protection configuration can be realized according to different requirements, including automatic switching of reserve cabinet, quick break, over current, low voltage, etc. Loads are varied, including transformers, motors, capacitors, lines and so on. Main components in the middle cabinet: high voltage circuit breaker (or vacuum contactor), grounding switch, transformer, microprocessor protection device, etc.