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EP-4742468-A1 - SWITCHGEAR

EP4742468A1EP 4742468 A1EP4742468 A1EP 4742468A1EP-4742468-A1

Abstract

The present invention relates to a switchgear (10), comprising: - a component (20); - a conduit (80); - a flap (30); and - a deflector (60); wherein the flap and the deflector are located in the conduit; wherein when the flap is open air (40) from outside the switchgear can enter the switchgear via the conduit; wherein when the flap is closed air and/or gas is inhibited from exiting the switchgear via the conduit; wherein in normal operation when the flap is open the air from outside the switchgear is configured to enter the conduit and flow past the flap and then flow past the deflector and be directed to the component to cool the component; and wherein in the event of an internal arc within the switchgear the flap is configured to close due to the internal arc pressure and gas flow (90) caused by the internal arc.

Inventors

  • NOVAK, ONDREJ

Assignees

  • ABB SCHWEIZ AG

Dates

Publication Date
20260513
Application Date
20241107

Claims (15)

  1. A switchgear (10), comprising: - a component (20); - a conduit (80); - a flap (30); and - a deflector (60); wherein the flap and the deflector are located in the conduit; wherein when the flap is open air (40) from outside the switchgear can enter the switchgear via the conduit; wherein when the flap is closed air and/or gas is inhibited from exiting the switchgear via the conduit; wherein in normal operation when the flap is open the air from outside the switchgear is configured to enter the conduit and flow past the flap and then flow past the deflector and be directed to the component to cool the component; and wherein in the event of an internal arc within the switchgear the flap is configured to close due to the internal arc pressure and gas flow (90) caused by the internal arc.
  2. Switchgear according to claim 1, wherein in the event of an internal arc within the switchgear the deflector is configured to deform.
  3. Switchgear according to any of claims 1-2, wherein the flap is rotatably connected to a first side wall of the conduit, wherein in the event of the internal arc within the switchgear the flap is configured rotate with an edge portion of the flap being moved toward and brought into contact with a second side wall of the conduit to close the flap due to the internal arc pressure and gas flow caused by the internal arc, wherein in normal operation when the flap is open a first end of the deflector is located adjacent to the edge portion of the flap, wherein in normal operation when the flap is open the air from outside the switchgear is configured to enter the conduit and flow past the flap between the edge portion of the flap and the second side wall of the conduit flow past the first end of the deflector and then flow between a first side of the deflector and the second side wall of the conduit.
  4. Switchgear according to claim 3, wherein in normal operation when the flap is open the first end of the deflector is connected to the edge portion of the flap.
  5. Switchgear according to claim 4, wherein in normal operation when the flap is open the first end of the deflector is fitted to the edge portion of the flap without being fixedly attached to the edge portion of the flap.
  6. Switchgear according to claim 4, wherein in normal operation when the flap is open the first end of the deflector is connected to the edge portion of the flap via at least one bolt.
  7. Switchgear according to any of claims 4-6, wherein in the event of an internal arc within the switchgear the first end of the deflector is configured to detach from the edge portion of the flap due to the internal arc pressure and gas flow caused by the internal arc.
  8. Switchgear according to claim 7 when dependent upon claim 6, wherein in the event of an internal arc within the switchgear the at least one bolt is configured to break due to the internal arc pressure and gas flow caused by the internal arc
  9. Switchgear according to any of claims 3-8, wherein in the event of an internal arc within the switchgear a second side deflector opposite to the first side of the deflector is configured to be moved towards the first side of the conduit due to the internal arc pressure and gas flow caused by the internal arc.
  10. Switchgear according to any of claims 1-9, wherein the deflector is configured to withstand air velocities of 1-5 m/s.
  11. Switchgear according to claim 8, wherein the deflector is configured not to deform when subjected to air velocities of 1-5 m/s.
  12. Switchgear according to any of claims 1-12, wherein the deflector is configured not to withstand air velocities of 50-150 m/s.
  13. Switchgear according to claim 13, wherein the deflector is configured to deform and/or crumple when subjected to air velocities of 50-150 m/s.
  14. Switchgear according to any of claims 1-13, wherein the deflector comprises at least one hole (70) along its length, and wherein the one or more holes are configured to enable air to flow through the deflector.
  15. Switchgear according to any of claims 1-14, wherein the deflector comprises plastic.

Description

FIELD OF THE INVENTION The present invention relates a switchgear. BACKGROUND OF THE INVENTION A switchgear 10, such as a medium voltage swithgear, is required to protect people and other equiopment in the locality from an internal arc. A switchgear can have vents that enable cooling air 40 to enter the swithgear to cool hot components 20 within the switchgear. An internal arc, if it occurs, generates a pressure wave followed by hot gases. Therefore, switchgears are equipped with internal arc flaps 30 that close due to the effect of pressure wave and thus prevent any pressure and or hot gasses from leaving switchgear compartment via the cooling vents. However, an internal arc flap decreases cooling by convection due to two factors. The first factor is that a constriction of cross sectional area that airflow can pass through is caused by the flap. This increases pressure loss and thus causes momentum energy loss from the flow. The second factor is that the flap causes large flow separation, that creates a large flow wake 50. This wake takes a lot of momentum energy from the flow and thus decreases the mass flow rate of cooling air coming through the flap. This situation is shown schematically in Fig. 1. There is a need to address this situation. SUMMARY OF THE INVENTION Therefore, it would be advantageous to provide an improved technique for operation of an internal arc flap of a swithgear. The object of the present invention is solved with the subject matter of the independent claim, wherein further embodiments are incorporated in the dependent claims. In an aspect, there is provided a switchgear, comprising: a component;a conduit;a flap; anda deflector. The flap and the deflector are located in the conduit. When the flap is open air from outside the switchgear can enter the switchgear via the conduit. When the flap is closed air and/or gas is inhibited from exiting the switchgear via the conduit. In normal operation when the flap is open the air from outside the switchgear is configured to enter the conduit and flow past the flap and then flow past the deflector and be directed to the component to cool the component. In the event of an internal arc within the switchgear the flap is configured to close due to the internal arc pressure and gas flow caused by the internal arc. Thus, normally when air flows into a switchgear past an internal arc flap, the air flow separates as it flows pas the flap and a wake is formed, and momentum energy is lost from the air flow and the ability to cool is reduced, however the deflector now stops the flow from separating and the wake from forming behind the flap, and momentum is not lost and there is an increased mass flow rate of cooling air leading to improved cooling of the component. It is to be noted that in normal operation air can enter the conduit to cool the hot component via natural convection or be directed and forced into the conduit via a fan, for example at the entrance to the conduit. In an example, in the event of an internal arc within the switchgear the deflector is configured to deform. In an example, the flap is rotatably connected to a first side wall of the conduit. In the event of the internal arc within the switchgear the flap is configured rotate with an edge portion of the flap being moved toward and brought into contact with a second side wall of the conduit to close the flap due to the internal arc pressure and gas flow caused by the internal arc. In normal operation when the flap is open a first end of the deflector is located adjacent to the edge portion of the flap. In normal operation when the flap is open the air from outside the switchgear is configured to enter the conduit and flow past the flap between the edge portion of the flap and the second side wall of the conduit flow past the first end of the deflector and then flow between a first side of the deflector and the second side wall of the conduit. In an example, in normal operation when the flap is open the first end of the deflector is connected to the edge portion of the flap. In an example, in normal operation when the flap is open the first end of the deflector is fitted to the edge portion of the flap without being fixedly attached to the edge portion of the flap. In an example, in normal operation when the flap is open the first end of the deflector is connected to the edge portion of the flap via at least one bolt. In an example, in the event of an internal arc within the switchgear the first end of the deflector is configured to detach from the edge portion of the flap due to the internal arc pressure and gas flow caused by the internal arc. In an example, in the event of an internal arc within the switchgear the at least one bolt is configured to break due to the internal arc pressure and gas flow caused by the internal arc. In an example, in the event of an internal arc within the switchgear a second side deflector opposite to the first side of the deflector is configured to