パーフルオロカーボン液/気相およびSF₆ガス混合相における絶縁破壊特性

抄録

In the insulation design for power apparatuses which use perfluorocarbon (PFC) liquid, it is necessary to study for breakdown strength of the liquid/vapor under uniform field. Especially, for the device with SF₆, the breakdown strength is an important factor of the insulating engineering.
This paper presents the investigation on insulation characteristics of PFC liquid/vapor with and without SF₆, when the temperature is changed within 20-80°C. Experiments are performed using plane-plane electrode geometry in a closed system under AC and lightning impulse voltages. It is found that: (1) in the case of PFC vapor pressure above the liquid without SF₆, the breakdown strength is affected a little in the liquid phase by temperature rise, while increases extremely in the vapor phase under the same condition;
(2) in the other case of a mixture pressure above the liquid with SF₆ under AC voltage, the breakdown strength of the mixture vapor phase is given by adding the contribution of the two components (PFC vapor and SF₆).