Passive arc protection for main breaker line side power conductors

Patent metadata

Field	Value
Publication number	US-9450387-B2
Application number	US-201414501946-A
Country	US
Kind code	B2
Filing date	Sep 30, 2014
Priority date	Apr 20, 2012
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

In a switchgear cabinet, the line side power conductors upstream of the main breaker are surrounded with arc attenuating/extinguishing channels and protective conduit in a location prior to the conductor's attachment to the main breaker. Thus, passive arc attenuation can be had prior to the breakers, Personal Protection Equipment (PPE) levels can be predicted and controlled, and the need for action by circuit breakers during an arcing event is substantially lessened.

First claim

What is claimed is:

1. An electrical apparatus for passive management of arc faults, the apparatus comprising:
a. a switchgear cabinet, the switchgear cabinet having therein:
b. a main breaker for interrupting all downstream power through the cabinet,
c. at least one branch breaker downstream of the main breaker for interrupting power to a branch circuit,
d. a multiple phase power distribution bus for delivering grid power into the switchgear cabinet and attaching to the line side connections of the main circuit breaker, and
e. an arc block structure located upstream of the line side connections of the main breaker, the arc block structure having phase barriers forming arc channels around a plurality of phases of the power distribution bus, the arc channels being of sufficient length and volume to attenuate an arc occurring therein.

2. The electrical apparatus of claim 1 wherein the arc channels are of sufficient length and volume to extinguish an arc occurring therein.

3. The electrical apparatus of claim 1 further comprising a metal enclosure at least partially surrounding the arc channels.

4. The electrical apparatus of claim 3 further comprising a vent pipe connected to the metal enclosure.

5. The electrical apparatus of claim 1 wherein the arc channels are connected to a plenum surrounding the plurality of phases.

6. The electrical apparatus of claim 5 wherein the plenum and arc channels each have an open end thereby providing flow-through ventilation.

7. The electrical apparatus of claim 1 wherein the power distribution bus is constructed of multiple sections producing changes in direction and orientation of the power conductor until it reaches the line side connections of the main breaker, and
the arc channels have fixed barriers surrounding each phase of the electrical conductors at uninsulated conductor joints thereof.

8. The electrical apparatus of claim 1 wherein the barriers have a length and shape wherein each of the arc channels and the plenum define a geometry configured to achieve an arc extinguishment based on a known voltage and current carried by the enclosure.

9. The electrical apparatus of claim 1 wherein the main breaker is a draw out breaker.

10. A method for limiting arc blast, extinguishing arcs, and ventilating conductors in an electrical enclosure containing electrical circuit conductors and a main circuit interrupting device connected to the electrical current conductors, the method comprising:
forming arc channels, respectively, around each electrical circuit conductor connected above the main circuit interrupting device, the arc channels having a first end and a second end;
the arc channels having a length sufficient to achieve an arc voltage attenuation such that an interruption of an arc current occurs within a predetermined time period; and
coupling the first end to a conduit, the conduit providing protective channels surrounding each phase of the electrical current conductors;
coupling the second end to a plenum, the plenum having a volume sufficient to achieve arc plasma cooling rates sufficient to extinguish the arc in accordance with a predetermined test requirement.

11. An arc management system with a passive arc attenuator, comprising:
a) electrical equipment having exposed electrical conductors;
b) a cabinet separating the electrical equipment from an outside environment;
c) an arc channel within the cabinet and surrounding the electrical conductors upstream of a main circuit breaker of the cabinet,
d) the arc channel forming a shape and volume sufficient for the attenuation of an arc therein.

12. The arc management system of claim 11 wherein the arc channel is surrounded by a metal enclosure within the cabinet.

13. The arc management system of claim 11 wherein
the arc channel is a channel of sufficient length and cross section to attenuate the arc.

14. The arc management system of claim 11 wherein
the arc channel is a channel of sufficient length and cross section to extinguish the arc.

Assignees

• Schneider Electric Usa Inc

Inventors

• Faber Timothy R
• Woodson Cameron L

Classifications

• H02B11/04 Primary

  Isolating-contacts, e.g. mountings or shieldings · CPC title

• H02B1/20

  Bus-bar or other wiring layouts, e.g. in cubicles, in switchyards (installations of bus-bars H02G5/00) · CPC title

• H02B1/56

  Cooling; Ventilation · CPC title

• H02B13/025 Primary

  Safety arrangements, e.g. in case of excessive pressure or fire due to electrical defect · CPC title