| 摘要 |
<p>PURPOSE: To achieve a stable detection without any dipping and easily confirm ventilation state by forming a protruding part on the floor surface of a utility tunnel and a recess which is blocked by a member with a plurality of small holes on the protruding part and detecting oxygen concentration inside. CONSTITUTION: A protruding part 17 is formed on a floor surface 15 of a utility tunnel 4, a recessed part 18 as a gas leakage detection room is provided at the detection part 17, and the leakage of SF6 gas 21 from a gas insulation bus is detected by an oxygen concentration measuring instrument 20 inside. Therefore, even if water enters the utility tunnel 4, it does not flow into the recessed part 18, thus preventing the operation delay and failure of the measuring instrument 20. The contact time between the gas 21 and the measuring instrument 20 can be fully secured for a stable detection for a long time. Further, when the gas 21 leaks, is ventilated, and a recovery operation is performed, the dilution of the gas 21 inside the recessed part 18 starts at a small hole of a blocking member 19 after air inside the utility tunnel 4 advances. Therefore, by confirming that the oxygen concentration inside the recessed part 18 by a measuring instrument 20, the recovery operation can be started safely.</p> |
