| 摘要 |
PURPOSE:To surely detect the defect of airtight sealing even in case of small difference between internal and external pressures by installing the detector for oxygen or nitrogen on the top of the airtight equipment containing SF6 gas. CONSTITUTION:If SF6 gas 2 is sealed at 30 deg.C in the airtight SF6 gas container 1 with slightly higher pressure than the atmospheric pressure, the pressure of the gas 2 is nearly equal to the atmospheric pressure when the transformer is not operated, and becomes lower than the atmospheric pressure when the temperature is below 0 deg.C. If the sealing is broken in this state, the air 4 flows into the container 1 through the defect part. As the specific weight of the air is smaller than the one of SF6 gas, the air moves upward with time. The detector for oxygen or nitrogen installed on the top of the tank 8 detects oxygen or nitrogen in the air 4, so that the suitable measures can be performed and the serious accidents caused by the decrease of insulating strength, such as ground fault and short-circuit, can be prevented. |
