真空バルブの絶縡破壊確率分布と2点切り真空遮断器の絶縡破壊特性の検討

摘要

高真空は真空遮断器等の高電圧機器の絶縁媒体として古rnくから用いられているが，最近になってSF_6ガスが排出量rn削減の対象ガスとして指定されたため，環境負荷の少ないrn絶縁媒体として見直されている。例えば，断路器や接地装rn置の絶縁媒体に高真空を用いた真空断路器や接地装置が開rn発され，今後真空遮断器の高電圧化など適用範囲が拡大rnしていくものと考えられる。%To investigate the reliability of equipment of vacuum insulation, a study was carried out to clarify breakdown probability distributions in vacuum gap. Further, a double-break vacuum circuit breaker was investigated for breakdown probability distribution. The test results show that the breakdown probability distribution of the vacuum gap can be represented by a Weibull distribution using a location parameter, which shows the voltage that permits a zero breakdown probability. The location parameter obtained from Weibull plot depends on electrode area. The shape parameter obtained from Weibull plot of vacuum gap was 10～14, and is constant irrespective non-uniform field factor. The breakdown probability distribution after no-load switching can be represented by Weibull distribution using a location parameter. The shape parameter after no-load switching was 6 ～ 8.5, and is constant, irrespective of gap length. This indicates that the scatter of breakdown voltage was increased by no-load switching. If the vacuum circuit breaker uses a double break, breakdown probability at low voltage becomes lower than single-break probability. Although potential distribution is a concern in the double-break vacuum cuicuit breaker, its insulation reliability is better than that of the single-break vacuum interrupter even if the bias of the vacuum interrupter's sharing voltage is taken into account.