Circuit breaker having internal transient recovery voltage capacitor assembly

Abstract

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. By being connected in parallel across the contact, the capacitor assembly can be connected to either side of the contact, regardless of whether the contact is in an open position or closed position.

Description

Background technique [0001] Embodiments of the invention relate generally to circuit breakers. More particularly, but not exclusively, embodiments of the present invention relate to circuit breakers having internal transient recovery voltage (TRV) capacitor assemblies connected in parallel across the circuit breaker contacts. [0002] Various types of circuit breakers for selectively breaking and closing electrical connections use sealed housings or enclosures filled with a liquid or gaseous dielectric insulating medium including, for example, sulfur hexafluoride (SF 6 ), and other insulating gases and liquids. The dielectric insulation within the sealed housing is at least useful in attempting to reduce and / or extinguish arcing and prevent current flow from the electrically active components and at least the housing, which may at least be associated with opening of the circuit breaker contacts. Moreover, such dielectric insulation may at least attempt to prevent or extingui...

AI Technical Summary

Problems solved by technology

However, such external line-to-ground TRV capacitors typically require additional external mounting components and associated space, including, for example, components for externally mounting the external line-to-ground TRV capacitors to the circuit breaker or a separate base, which may Increases manufacturing cost and expense, and may complicate providing adequate clearance for at least some components associated with the circuit breaker

Also, external line-to-ground TRV capacitors are typically only electrically coupled to one side of the breaker, so may not be effective for faults on both sides of the breaker contacts

In addition, the external line-to-ground TRV capacitors may be located a relatively large distance from the contacts of the circuit breaker as they are external components, which may adversely affect the efficiency of the external line-to-ground TRV capacitors

Furthermore, attempts to address the detrimental effect of such a distance between the external line-to-ground TRV capacitors and the breaker contacts have often involved the use of capacitors with relatively large capacitances, which at least lead to increased cost of the device

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