A circuit closer includes: a vacuum interrupter in which one of a pair of electrodes oppositely disposed in a vacuum vessel, wherein a gap d between the pair of electrodes always satisfies d>0, and a gap d1 between the pair of electrodes in a state in which closing of a circuit is completed, is shorter than a distance d2 at which insulation between the pair of electrodes is broken down by a charge voltage V of the circuit that is to be closed, and is longer than a distance d3 at which the pair of electrodes are bridged by a deposition of an electrode metal after a closing operation, the deposition resulting from evaporation caused by heat of an arc generated when the circuit is closed.

An arrester including a metal oxide varistor (MOV) disc and a spark gap assembly electrically connected in series with the MOV disc. The spark gap assembly includes a spark gap and a frequency-dependent grading capacitor electrically connected in parallel with the spark gap.

An arrester including a metal oxide varistor (MOV) disc and a spark gap assembly electrically connected in series with the MOV disc. The spark gap assembly includes a spark gap and a frequency-dependent grading capacitor electrically connected in parallel with the spark gap.

A triggered vacuum gap (TVG) device that has application as a closing switch for synchronized closing in distribution and transmission power systems. The TVG device controllably sustains a current arc in the device through initial current zeros created by power system transients and, thereby, prevents premature interruption of the closing operation. The TVG device includes main electrodes defining a vacuum gap therebetween and a triggering electrode providing a triggering gap between one main electrode and the triggering electrode. The TVG device also includes a triggering circuit having a high voltage impulse source that supplies a fast rising impulse voltage to the one main electrode and the triggering electrode for creation of a plasma to provide an initial breakdown of the triggering gap and a low voltage unidirectional current source that supplies current to the one main electrode and the triggering electrode once the first triggering gap breakdown has occurred.

A triggered vacuum gap (TVG) device that has application as a closing switch for synchronized closing in distribution and transmission power systems. The TVG device controllably sustains a current arc in the device through initial current zeros created by power system transients and, thereby, prevents premature interruption of the closing operation. The TVG device includes main electrodes defining a vacuum gap therebetween and a triggering electrode providing a triggering gap between one main electrode and the triggering electrode. The TVG device also includes a triggering circuit having a high voltage impulse source that supplies a fast rising impulse voltage to the one main electrode and the triggering electrode for creation of a plasma to provide an initial breakdown of the triggering gap and a low voltage unidirectional current source that supplies current to the one main electrode and the triggering electrode once the first triggering gap breakdown has occurred.

The occurrence of an upward streamer is effectively suppressed by reducing a positively charged region formed around a lightning protection device as much as possible. The lightning protection device includes: an inner electrode body 2 which is grounded; an outer electrode body 3 which is provided so as to enclose the inner electrode body 2 with a predetermined gap G from the inner electrode body 2; an electrical insulator S which is provided in the gap G to hold the inner electrode body 2 and the outer electrode body 3 in a state of being electrically insulated from each other; and a support body for the inner electrode body, in which the inner electrode body 2 is formed in a substantially spherical shape, the outer electrode body 3 is formed in a spherical shell shape similar to an outer surface shape of the inner electrode body 2, and substantially an entire surface of the inner electrode body 2 is covered by the outer electrode body 3.

The occurrence of an upward streamer is effectively suppressed by reducing a positively charged region formed around a lightning protection device as much as possible. The lightning protection device includes: an inner electrode body 2 which is grounded; an outer electrode body 3 which is provided so as to enclose the inner electrode body 2 with a predetermined gap G from the inner electrode body 2; an electrical insulator S which is provided in the gap G to hold the inner electrode body 2 and the outer electrode body 3 in a state of being electrically insulated from each other; and a support body for the inner electrode body, in which the inner electrode body 2 is formed in a substantially spherical shape, the outer electrode body 3 is formed in a spherical shell shape similar to an outer surface shape of the inner electrode body 2, and substantially an entire surface of the inner electrode body 2 is covered by the outer electrode body 3.

A separating device for a surge arrester has a housing and a fuse is arranged in the housing. There is also described an arrangement that includes a surge arrester and a separating device as described.

A circuit closer includes: a vacuum interrupter in which one of a pair of electrodes oppositely disposed in a vacuum vessel, wherein a gap d between the pair of electrodes always satisfies d>0, and a gap d1 between the pair of electrodes in a state in which closing of a circuit is completed, is shorter than a distance d2 at which insulation between the pair of electrodes is broken down by a charge voltage V of the circuit that is to be closed, and is longer than a distance d3 at which the pair of electrodes are bridged by a deposition of an electrode metal after a closing operation, the deposition resulting from evaporation caused by heat of an arc generated when the circuit is closed.

A circuit closer includes: a vacuum interrupter in which one of a pair of electrodes oppositely disposed in a vacuum vessel, wherein a gap d between the pair of electrodes always satisfies d>0, and a gap d1 between the pair of electrodes in a state in which closing of a circuit is completed, is shorter than a distance d2 at which insulation between the pair of electrodes is broken down by a charge voltage V of the circuit that is to be closed, and is longer than a distance d3 at which the pair of electrodes are bridged by a deposition of an electrode metal after a closing operation, the deposition resulting from evaporation caused by heat of an arc generated when the circuit is closed.