A circuit breaker having at least one capacitor assembly connected in parallel across a contact of the circuit breaker. The capacitor assembly can be housed with the contact within a sealed enclosure of the circuit breaker. The enclosure can be configured to house an insulating medium that is configured to reduce or quench an arc(s) that may form at least when the contact of the circuit breaker is displaced from a closed position to an open position. The capacitor assembly, which includes a transient recovery voltage (TRV) capacitor, can be configured to delay terminal fault and short line fault TRV and the rate of rise of the initial TRV (ITRV) that can appear across the open contact of the circuit breaker.

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 circuit breaker having at least one capacitor assembly connected in parallel across a contact of the circuit breaker. The capacitor assembly can be housed with the contact within a sealed enclosure of the circuit breaker. The enclosure can be configured to house an insulating medium that is configured to reduce or quench an arc(s) that may form at least when the contact of the circuit breaker is displaced from a closed position to an open position. The capacitor assembly, which includes a transient recovery voltage (TRV) capacitor, can be configured to delay terminal fault and short line fault TRV and the rate of rise of the initial TRV (ITRV) that can appear across the open contact of the circuit breaker.

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.