Gas insulated switchgear and system

The invention relates to the field of power distribution of a medium-voltage electric power transformer, and specifically relates to gas insulated switchgear and a system. The equipment comprises a bus three-station isolation switch room and a circuit breaker room; the bus three-station isolation switch room has a first shell; a wall bushing of the bus three-station isolation switch room is used for being connected with a main bus connector arranged on the exterior of the first shell; the circuit breaker room is arranged below the bus three-station isolation switch room; the circuit breaker room has a second shell; the second shell is fixedly connected to the first shell; and the size of the second shell is larger than that of the first shell. When the whole gas insulated switchgear and other gas insulated switchgear are combined, a certain distance is kept between the adjacent two bus three-station isolation switch rooms, so that whether main bus connection is proper or not can be observed from the outer sid