A breaking device includes an interrupting section including interrupting units in which main interrupters, impedance circuits, and unit arresters are connected in parallel to each other, the main interrupters being connected in series, a resonant circuit section including a reactor, a capacitor, and a closing switch and connected in parallel to the interrupting section, and an all-point arrester connected in parallel to the interrupting section via the reactor. The clamping voltages of the unit arresters are equal among the interrupting units, and are in the range of 1.1 to 1.6 times the value obtained by dividing the clamping voltage of the all-point arrester by the number of the interrupting units connected in series in the interrupting section.

A switching device includes: two interrupter units connected in series; at least one drive unit for moving at least one contact; and two control capacitors, each of which is connected in parallel with the interrupter units. At least one control capacitor has mechanically movable components for changing the capacitance, and at least one of these components is mechanically coupled to the drive unit.

Various embodiments may include a voltage switch having two terminals linked by an operating current path comprising a mechanical switch, and having means of generating a counter voltage to the voltage in the operating path. In some embodiments, there are: two terminals linked by an operating current path comprising a mechanical switch; a transformer having a primary side connected in series with the mechanical switch in the operating current path; a voltage source connected to a secondary side of the transformer; and a switch connected in series with the voltage source.

A switching module for use in a high voltage switch includes: a vacuum interrupter (VI), an elastomeric insulating sleeve disposed around the VI; an insulating housing molded around the VI and the sleeve; and a pair of grading capacitors. Each grading capacitor includes an inner and an outer electrode while insulation between the electrodes is solid insulation of the housing molded at the time when the housing is molded. One of the electrodes is galvanically connected to the fixed contact through a first terminal in the switching module and the other electrode is galvanically connected to the moving contact through a second terminal in the switching module. The capacitance of the first grading capacitor is substantially equal to the capacitance of the second grading capacitor.

A switching module for use in a high voltage switch includes: a vacuum interrupter (VI), an elastomeric insulating sleeve disposed around the VI; an insulating housing molded around the VI and the sleeve; and a pair of grading capacitors. Each grading capacitor includes an inner and an outer electrode while insulation between the electrodes is solid insulation of the housing molded at the time when the housing is molded. One of the electrodes is galvanically connected to the fixed contact through a first terminal in the switching module and the other electrode is galvanically connected to the moving contact through a second terminal in the switching module. The capacitance of the first grading capacitor is substantially equal to the capacitance of the second grading capacitor.

A voltage dividing capacitor (1) arranged parallel to a vacuum interrupter (2) has a long narrow cylindrical-shaped capacitor series (16) that is configured by a plurality of capacitor elements (15) being connected with connecting screws. One end of the capacitor series (16) is supported by a fixed supporting unit (25), and the other end id supported by a movable supporting unit (26) so as to allow thermal expansion and contraction. A insulation tube (31) fixed to the movable supporting unit (26) has a short length, and only a first capacitor element (15A) is fitted into the insulation tube (31). Since a portion where high electric field appears is a middle of five capacitor elements (15) and electric field at an end portion of the capacitor series (16) is low, forming of triple junction at the portion of the high electric field is avoided.

A DC circuit breaker system includes a first mechanical switch, a first parallel capacitor connecting a first terminal and a second terminal of the first mechanical switch, a second mechanical switch in series with the first mechanical switch, a second parallel capacitor connecting a first terminal and a second terminal of the second mechanical switch, a first diode connecting the first terminal and the second terminal; and a second diode connecting the first terminal and the second terminal. The first mechanical switch separates contacts in response to a fault current; the second mechanical switch separates contacts in response to the fault current; and opening the first and second mechanical switches and turning off the first and second diodes reverses current flow and clears a current fault. The DC circuit breaker system may also be equipped with a surge arrestor at its input and a freewheeling diode at its output.

A vacuum circuit breaker includes: a plurality of vacuum valves each of which includes: a cylindrical vacuum container; a fixed electrode fixed inside the vacuum container; a movable conductor that protrudes from the inside of the vacuum container to the outside of the vacuum container and is movable in a direction of a center axis of the vacuum container; and a movable electrode that moves together with the movable conductor inside the vacuum container to be capable of being separated from the fixed electrode and coming into contact with the fixed electrode, the plurality of vacuum valves being connected in series with each other; and a cylindrical tank that accommodates the plurality of vacuum valves. The plurality of vacuum valves include at least two vacuum valves adjacent to each other in a direction intersecting a center axis of the tank.

Various embodiments may include a voltage switch having two terminals linked by an operating current path comprising a mechanical switch, and having means of generating a counter voltage to the voltage in the operating path. In some embodiments, there are: two terminals linked by an operating current path comprising a mechanical switch; a transformer having a primary side connected in series with the mechanical switch in the operating current path; a voltage source connected to a secondary side of the transformer; and a switch connected in series with the voltage source.

A voltage dividing capacitor (1) arranged parallel to a vacuum interrupter (2) has a long narrow cylindrical-shaped capacitor series (16) that is configured by a plurality of capacitor elements (15) being connected with connecting screws. One end of the capacitor series (16) is supported by a fixed supporting unit (25), and the other end id supported by a movable supporting unit (26) so as to allow thermal expansion and contraction. A insulation tube (31) fixed to the movable supporting unit (26) has a short length, and only a first capacitor element (15A) is fitted into the insulation tube (31). Since a portion where high electric field appears is a middle of five capacitor elements (15) and electric field at an end portion of the capacitor series (16) is low, forming of triple junction at the portion of the high electric field is avoided.