| 摘要 |
<p>PURPOSE:To easily pick out only the signal from a gas flow due to the partial discharge by detecting the signal corresponding to the flow of the insulation gas which are equipped respectively for each phase of a phase separate type gas insulation electric device and comparing the outputs of this detecting signal mutually. CONSTITUTION:In case when the partial discharge has been occurring in an a-phase, the gas flow 13a due to the partial discharge of the a-phase and the gas flow 14a due to a thermal convection are detected and measured by a gas detecting element 5a and a gas flowmeter 6a. The output signal from this flowmeter 6a is the output signal of a form combined by both the gas flow 13a and 14a. Here, in case when the partial discharges have not been occurring in the a-phase and a b-phase, the output signals of the b-phase and a c-phase are the signal due to the thermal convection alone. So, the gas flows due to the thermal convection of the a-phase, the b-phase and the c-phase are nearly the same for each phase because Joule's heat to be a generating source is nearly the same. And, by subtracting the output signal of the b-phase from the output signal of the a-phase using a comparator circuit 15, it is enabled to pick out only the output part of the gas flow due to the partial discharge and apply in the same way in case the discharges have occurred in the b-phase and the c-phase.</p> |
