| 摘要 |
<p>PURPOSE:To prevent entrance of the external air into an exclusive tank even in case a pressure tank is opened, by providing an exclusive tank having a hermetically sealed structure which is resistive to a little pressure difference and valves communicating with internal and external sides and also providing a gas insulated potential transformer. CONSTITUTION:A gas insulated potential transformer 3 is previously filled with insulation gas and is stored under the condition that an automatic valve 7 is closed. At the time of assembling, the transformer 3 is housed together with an exclusive tank 2 within a pressure tank 1. After the assembling of interior, the tank 1 undergoes sealing, vacuum exhaustion and supply of gas. Namely, in the case of vacuum exhaustion, the valve 7 operates and opens depending on a pressure difference between internal and external pressure. Therefore, an excessive pressure difference is not applied on the tank 2. For the supply of gas, the valve 7 operates and opens depending on the pressure difference when the tank 1 is filled with the insulation gas, the insulation gas flows into the tank 2 from the tank 1, not generating an excessive pressure difference. Thereby, the transformer 3 holds initial insulation performance and it is enough for the tank 2 to have the sealed structure which is resistive to an internal and external pressure difference of about 0.3-0.4kg/cm<2>.</p> |
