FIELD OF THE INVENTION
Embodiments of the invention in general relates to the technical field of power equipment, more particularly, torelates to release of hot gases inside switchgear room in case of Internal Arc fault in Medium Voltage, MV switchgear considering the safety of person near to switchgear.
BACKGROUND OF THE INVENTION
Electrical equipment such as circuit breakers are typically contained within arc electrically grounded resistant cabinets, intended to provide isolation for the components therein, and to protect personnel working around the circuit breaker from electrocution and from hot gases in the event of an electrical arc within the cabinet.
Medium voltage, MV, switchgear includes an exhaust system for venting of hot gases and debris particles generated by an electric arc under internal arc-fault conditions. During an arc fault explosion, temperature and pressure inside the switchgear increase very rapidly, and the rapid pressure build-up can damage the switchgear and its components.
The release of hot gases in case of internal arc fault inside the switchgear with reduced energy is of utmost importance for the safety of person near to switchgear and IEC requirements.
The prior art solutions uses extended duct design arrangement for release of these hot gasesin case of internal arc fault, which require additional space outside the switchgear room.
Reference is being made to US8101881B2, disclosing an exhaust system for exhausting gases and molten debris caused by an electric arc within a switchgear. The exhaust system includes a switchgear having lower and upper compartments and an exhaust unit externally mounted to the switchgear. A wall panel of the switchgear includes blow out panels coinciding with openings in the lower compartment and corresponding ventilation flaps in a top surface of the exhaust

unit to exhaust gas from the lower compartment out the blow out panels in a vertical direction, exiting through the flaps. The upper compartment includes ventilation flaps for exhausting gas in a vertical direction directly through the flaps and optionally through side-mounted blow out panels that communicate with the vertical vent path to the flaps in the top of the exhaust unit. A bus compartment in the exhaust unit includes a vent path to flaps in the top of the exhaust unit for exhausting gas produced by bus arcing.
US8101881B2 relates to a vertical exhaust system for arc-resistant switchgear. No arc deflector is used in US8101881B2. While, the present invention relates with adoption of arc chamber and in its arrangement of arc deflector to reduce the intensity of hot gases while coming out of structure.
Reference is being made to US8242395B2, disclosing a circuit breaker compartment arc flash venting system for a switchgear apparatus. The present invention also relates to enclosures for switchgear, panel boards, circuit breakers, and more particularly to an enclosure for low voltage switchgear and switchboard assemblies. The enclosure can be a walk-in type enclosure or a non-walk-in type enclosure. US8242395B2further provides a method and apparatus for channelling plasma (hot arc gasses) that are generated from an arc. The circuit breaker compartment arc flash venting system is an integral part of an arc resistant switchgear assembly. The arc flash venting system works in conjunction with the bus insulation and ventilation systems in the switchgear apparatus to channel hot arc gasses (plasma) from a breaker compartment in the event of an internal arcing fault in the breaker compartment. The gases are channelled to exit the upper rear of the breaker compartment and into the insulated section bus compartment. The hot arc gases and other particulates then travel upward through the section bus compartment where they are routed to and safely discharged from the vent structure on the roof of the switchgear apparatus.
US8242395B2provides a method and apparatus for channelling plasma (hot arc gasses) that are generated from an arc. US8242395B2encompasses a circuit breaker compartment arc flash venting system for a switchgear apparatus. The

method of venting the hot gases is different in US8242395B2and in the present invention. Contrary to US8242395B2, the present invention relates to adoption of arc chamber and in its arrangement of arc deflector to reduce the intensity of hot gases while coming out of structure.
Nowadays due to some space constraints, the release of hot gases outside the switchgear room through extended duct is not possible. In view of the prior art, there is a dire need for an arrangement facilitating release of hot gases inside switchgear room in case of Internal Arc fault in MV switchgear and to overcome the additional requirement of additional space of prior art solutions, without compromising the safety of the person near to switchgear and IEC requirement.
SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
According to one aspect of the present invention^ medium voltage switchgear system comprising: a switchgear; an arc chamber; and an arc deflector assembly operably mounted atop the arc chamber to facilitate release of hot gases generated inside the switchgear in case of internal arc fault. The arc deflector consists of a top member, bottom member and a middle member adapted to support the top and bottom members, wherein the top member and bottom member having of the arc deflector comprises rectangular cutouts on their side flanges to provide the passage to hot gases generated inside the switchgear in case of internal arc fault. Thehorizontal faces of the top member and the bottom member is adapted to deflect the hot gases generated to the rectangular cutouts with reduced energy for the release of hot gases.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The above and other aspects, features and advantages of the embodiments of the present disclosure will be more apparent in the following description taken in conjunction with the accompanying drawings, in which:
Figure 1 illustratesanarc deflector assembly to release hot gases mounted atop a Medium Voltage, MV, switchgear, according to an embodiment of the present invention.
Figure 2 illustratesan arc deflector assembly to release hot gases for use in Medium Voltage switchgear, according to an embodiment of the present invention.
Figure 3 illustrates an isometric projection of an arc deflector assembly to release hot gases for use in Medium Voltage switchgear, according to an embodiment of the present invention.
Figures 4A-Billustrate an arc deflector assembly to release hot gases for use in Medium Voltage switchgear and the corresponding gas flow direction within the arc deflector assembly, according to an embodiment of the present invention.
Figure 5 illustrates an arc deflector assembly to release hot gases in switchgear, according to prior art or existing systems.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be

noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.
It is to be understood that the singular forms "a,""an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.
The terminology used herein is for the purpose of describing particular various embodiments only and is not intended to be limiting of various embodiments. As used herein, the singular forms "a","an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features, integers, steps, operations, members,

components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and/or groups thereof. Also, Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
The present disclosure will now be described more fully with reference to the accompanying drawings, in which various embodiments of the present disclosure are shown. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the various embodiments set forth herein, rather, these various embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the present disclosure. Furthermore, a detailed description of other parts will not be provided not to make the present disclosure unclear. Like reference numerals in the drawings refer to like elements throughout.
The subject invention lies in an arc deflector used in MV switchgear to release hot gases inside switchgear room in case of internal arc fault.
According to an embodiment, as shown in Figures 1A-B,an arc deflector assembly mounted on the top of a switchgear facilitates leakage of hot gases from that deflector assembly only from the top side with reduced energy, in case of internal arc fault, which will not hamper the safety of person as well as IEC requirements.
Whenever an internal arc fault occurs inside the switchgear, hot gases accumulate inside the chamber and then come out though the arc deflector assembly. The deflector assembly facilitates deflection in path of the hot gases, such that the energy of hot gases are reduced significantly and they finally come out of the switchgear.
Asshown in Figure 1A, the switchgear (3) comprises of an arc chamber (2) and an arc deflector assembly (1) mounted atop the arc chamber. Once an internal arc fault occurs inside the switchgear (3), the hot gases accumulate inside the arc

chamber (2) and then come out from the top as shown, through the mounted arc deflector assembly (1).
In the existing systems, as shown in Figure 5, the switchgear is coupled to an extended duct to reach the switchgear room wall and guide the flue gas exhaust out of the room. This arrangement occupies more space and not at all effective in reducing the temperature and energy of the exhaust hot gases.
A switchgear system, as in Figure 3,comprisesa switchgear, an arc chamber and an arc deflector assembly. The medium voltage switchgear system comprises a switchgear (3); an arc chamber (2); and an arc deflector assembly (1) operably mounted atop the arc chamber (2) to facilitate release of hot gases generated inside the switchgear (3) in case of internal arc fault. The arc deflector assembly is mounted atop at a user defined angle, 30° or 40° or the like, so that the hot flue gases generated is released through the deflector assembly efficiently.Thehot gases are guided by a guiding plate coupled to the lower portion of the arc deflector assembly,to be released in a projectile manner,away from any equipment or personnel standing nearby the switchgear system, thereby ensuring safety.
As shown in Figure 4A, the arc deflector consists of a top member, a bottom member and a middle member adapted to support the top member and the bottom member, wherein the top member and bottom member of the arc deflector comprises rectangular cutouts on their side flanges to provide the passage to hot gases generated inside the switchgear in case of internal arc fault. The horizontal faces (flat surfaces) of the top member and the bottom member is adapted to deflect the hot gases generated to the rectangular cutouts for the release of hot gaseswith reduced energy and pressure.
According to an embodiment, the bottom member (A) (brown in colour) and the top member (B) (red in colour) are substantially similar in construction. The bottom member islike a continuous square-wave pattern structure, having a plurality of alternate flat surfaces which are spaced apart vertically. These flat surfaces are joined by perpendicular surfaces to give a substantially square-wave

pattern structure. Eachalternate flat surface has a substantially perpendicular surface on either side to join the flat surface with a preceding flat surface and a succeeding flat surface. These perpendicular surfaces have a plurality of rectangular cutouts to facilitate flow of flue gases upwards and outwards from the switchgear and the flat surfaces of the bottom plate obstruct the flow of the flue gasand deflects the gases generated to the rectangular cutouts.
The top member is similar to the bottom member as described above and placedhorizontally over the middle member and the bottom member, but in a perpendicular direction with respect to the bottom member to facilitate efficient flow of flue gases through the cutouts of the top member and the bottom member, as shown in Figure 4B. The middle member (green colour) comprises a frame with a plurality of rectangular flat surfaces coupled to the frame of the middle member, and these rectangular surfaces are spaced apart for flue gas flow and further facilitates fixing the top member and the bottom member with the middle member.
In the arc deflector assembly of the above embodiments, the top member, the middle member and the bottom member are preferentially made of mild steel. As per choice, the cutouts in the side flanges (perpendicular surfaces) of the top member and the bottom member can have any geometric shape - circle, ellipse, rectangle, square and the like, and can be also of varying size. The vertically spaced apart flat surfaces of the top member and the bottom member,and the rectangular flat surfaces of the middle member can have varying width.
Figure 4B shows the flow of the hot flue gases, generated inside the arc chamber, through the arc deflector assembly.
The bottom member (A) is mechanically coupled atop the arc chamber (2)and is adapted to receive the flue gases from the arc chamber. The flue gases flow through the rectangular cutouts of the bottom member and is directed inward into the bottom member, flows upward through the spaces of the rectangular flat

surfaces of the middle member, and finally moves outward through the rectangular cutouts of the top member with reduced energy and pressure.
Some of the non-limiting advantages of the arc deflector assembly to release hot gases for use in Medium Voltage switchgear are:
1. Facilitating release of hot gases inside switchgear room in case of internal arc fault in MV switchgear without compromising the safety of the person near to switchgear and IEC requirement.
2. To overcome the requirement of additional space of prior art solutions, to facilitate release of hot gases generated inside the switchgear room.
Although an arc deflector assembly to release hot gases for use in Medium Voltage switchgear has been described in language specific to structural features, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific methods or devices described herein. Rather, the specific features are disclosed as examples of implementations of an arc deflector assembly to release hot gases for use in Medium Voltage switchgear.

WE CLAIM:

1. Amedium voltage switchgear system comprising:
a switchgear (3);
an arc chamber (2); and
an arc deflector assembly (1) operably mounted atop the arc chamber (2) to facilitate release of hot gases generated inside the switchgear (3) in case of internal arc fault.
2. The system as claimed in claim 1, wherein the arc deflector consists of a top member, bottom member and a middle member adapted to support the top and bottom members.
3. The system as claimed in claim 2, wherein the top member and the bottom member have similar constructional layout, and the top member and the bottom member are coupled to the middle member such that the top member and the bottom member are perpendicular to each other in the same plane.
4. The system as claimed in claim 2, wherein the middle member comprises a frame with a plurality of rectangular flat surfaces are spaced apart and coupled to the frame of the middle member, to facilitate the gas flow.
5. The system as claimed in claim 2, wherein the top member and the bottom member have a square wave pattern shape, with a plurality of alternate flat surfaces (horizontal faces), vertically spaced apart, said each alternate flat surfacehas a substantially perpendicular surface on either side to join the flat surface with a precedingflat surface and a succeeding flat surface, to give said substantially square-wave pattern structure, and the flat surfaces of the top member and the bottom member are adapted to deflect the hot gases generated to the rectangular cutouts with reduced energy for the release of hot gases.
6. The system as claimed in claim 2, wherein the top member and bottom member have a plurality of substantially rectangular cutouts on their side

flanges (perpendicular surfaces) to provide passage of hot gases generated inside the switchgear (3) in case of internal arc fault.
7. The system as claimed in claim 1,wherein the arc deflector assembly is mounted atop at a user defined angle, 30° or 40° or the like, such that the hot gases generated is released through the deflector assembly efficiently.
8. The system as claimed in claim 1, wherein the arc deflector assembly further comprises a guiding plate coupled to the lower portion of the arc deflector assembly, to guide the gases realised by the deflector assembly and be released in a projectile manner, away from any equipment or personnel standing nearby the switchgear system to ensure safety.
9. The system as claimed in claim 1, wherein the top member, middle member and the bottom member of the arc deflector assembly is made of mild steel.
10. The system as claimed in claim 1, wherein the cutouts in the side flanges (perpendicular surfaces) of the top member and the bottom member can be of varying size and have any geometric shape - circle, ellipse, rectangle, square and the like, and the vertically spaced apart flat surfaces of the top member and the bottom member, and the rectangular flat surfaces of the middle member can have varying width.