Patent ID: 8189325

Claim:
A switchgear comprising: a casing partitioned into at least four chambers comprising a high voltage bus bar chamber, which contains at least bus bars and cable heads, a high voltage device chamber containing at least circuit breakers and a low voltage control chamber containing at least a relay and measurement devices, wherein the casing is constituted by a rear wall, a front wall opposed to the rear wall, a bottom wall, a top wall opposed to the bottom wall, and side walls each connected to the top wall, bottom wall, front wall and rear wall, the rear wall having a first suction port disposed at a lower part thereof, wherein the high voltage bus bar chamber, the high voltage device chamber and the low voltage control chamber are communicated and air passing through the chambers is discharged from a first discharging port of the casing, the first suction port being provided with a first filter, a second suction port provided with a third filter being disposed between the high voltage bus bar chamber and the low voltage control chamber, wherein bus bars electrically connecting the high voltage devices in the high voltage device chamber and connecting bars connecting the adjoining bus bars and the cable heads are covered and insulated with solid insulators, and wherein the second suction port has a smaller cross sectional area than the first suction port, and the third filter has a smaller pore size than the first filter.