The present subject matter described herein, in general, relates to the field of switchgears, and more particularly to an arrangement of arc absorber/diffuser used in a gas insulated switchgear (GIS) for a type testing purpose.
BACKGROUND
The Gas Insulated Switchgear (GIS) is generally used for the distribution of power supply. It has many variants according to its application. Generally, it has three position i.e.; ON - OFF - EARTH. All Switchgear performs the function of eliminating fault from the Power System. Faults may be external faults that may include but not limited to a Single LG Faults, LLG fault etc., or Internal Faults due to Sudden rise in voltage. All the faults are fatal to the electrical System and equipments. But this Internal Arc fault becomes more critical fault as it not only damages the equipment but also it puts human life in danger.
Internal Arc Fault involves large amount of energy dissipation i.e., 100s of MJ in a very short time in millisecond. This large amount of heat dissipation in turn results in pressure rise and temperature rise inside the Faulted Switchgear compartments. Due to this, the kinetic energy of the gas in increased which ultimately puts mechanical stresses on the compartment. Hence to ensure the release of these gas in same room with safety, it is important to reduce the kinetic energy and also temperature the gas before its release.
In the conventional design, pressure relief flaps are given on the walls of compartments, so whenever there is sudden rise in pressure these flaps will open give the path for the hot gases to enter Arc duct. These arc ducts then channel the hot gases and molten particles out of the room where the switchgear is installed. Hence above a certain pressure this flaps get opened up and hot gases are taken out of the compartment via Arc duct and released in Atmosphere. This is very

easy and simple practice but not environment friendly. Also, in applications such as chemical industries, this direct emission of hot gases can be hazardous.
For prior art, reference is made to a prior art CA2233484C which is related to arc chamber providing a path for releasing from said enclosure pressure and hot gases produced by an electrical arc fault associated with an electrical component in one of said compartments. While in our Patent, the overall kinetic energy of Arc is reduced.
Further, reference is made to a prior art WO1998019377A1 which uses Arc Absorber Device for reducing pressure and heat. This is achieved by increasing the overall flow of gas.
However, so far none of the prior art discloses a solution to bring down the kinetic energy of arc gases.
Thus, in view of the drawbacks of the prior art, there exists a dire need for an improved arrangement of arc absorber which will result in releasing hot gases inside the room ensuring safety which is very crucial.
SUMMARY OF THE INVENTION:
This summary is provided to introduce a selection of concepts in a simplified format that is further described in the detailed description. This summary is not intended to identify key or essential inventive concepts.
An objective of the present invention is to provide an arc absorber/diffuser in a gas insulated switchgear system to channel the hot gases via the arc duct so that it ensures persons safety whenever an internal arc fault occurs.

Another objective of the present invention is to provide an arc absorber arrangement so that the overall kinetic energy of arc gases is brought down by using layered perforated sheets.
Yet another objective of the present invention is to arrange the arc absorber in such a way that it can be fitted in series of coupled gas insulated switchgear panels. It can be placed in arc duct path such that it will absorb the heat and kinetic energy of exhaust gases.
Accordingly, in one aspect, the present invention provides an arc absorber for at least a switchgear unit, wherein said arc absorber comprising at least a four layered perforated sheet metal box. The four layered perforated sheet metal box includes:
• a first layer of said four layered perforated sheet metal box having at least a perforated sheet metal where hot gas enters through an air duct;
• a second layer of said four layered perforated sheet metal box is an assembly of at least five independent layers;
• a third layer of said four layered perforated sheet metal box where gas enters from said second layer, wherein said third layer having a honey comb-like structure where large amount of heat absorption of said hot gas takes place; and
• a fourth layer having a structure similar to said second layer, wherein said fourth layer allows channeling of gases in a direction before releasing said gases.
In one implementation, the five independent layers of said second layer further comprises: at least two packing sheet layers having plurality of perforations assembled at a top and at a bottom, wherein said layer serves a heat exchanger.

In one implementation, the second layer comprises a thin sheet layer sandwiched between said two packing sheet layer, which allows to absorb heat from said hot gases, which allows to absorb heat from said hot gases.
In one implementation, the thin sheets having a thickness of 1-2 mm with a diameter of 3-4mm holes or a simple wire-mesh of 1-2 mm diameter.
In one implementation, the arc absorber as claimed in claim 1, wherein said third layer having thickness of 5-6 mm.
In second aspect, the present invention provides an arc diffuser comprising a perforated sheet metal box, wherein said box comprising at least five layers stacked together to converge and diverge the hot gases,
Wherein,
• a first layer of said five layers includes a plurality of perforations of at least a 2-3mm diameter;
• a second layer of said five layers having a plurality of perforations of at least a 1.5-2.5mm diameter;
• a third layer of said five layers having a plurality of perforations of at least a 0.5-1.5mm diameter;
• a fourth layer of said five layers having a plurality of perforations of at least a 1.5-2.5mm diameter; and the last layer again having a plurality of perforations of at least a 2-3 mm diameter.
By the various implementation, the present invention is able to release the gas inside the room consuming all the energy by either deflecting or absorbing the hot gases. Further, the overall kinetic energy of arc gases is brought down by using layered perforated sheets. The arrangement of arc absorber which will result in releasing hot gases inside the room ensuring safety is very crucial. This in turn can improve the overall designs of switchgear to channel the hot gases via the Arc

duct so that it ensures persons safety whenever an internal arc fault occurs. Also, this arrangement can be used for single gas insulated switchgear panel as well as series of coupled gas insulated switchgear panels.
The above aspects and the advantages will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
It is appreciated that the drawings provided in the present disclosure only illustrate application examples of the present disclosure and are therefore not to be construed as limiting its scope. The foregoing disclosure provides additional information with additional specificity and details with the accompanying drawings, which are listed below for quick reference.
Figure 1: shows the flow of hot gases from a faulted compartment to arc duct, according to the present invention.
Figure 2: shows the arc diffuser arrangement on top of arc duct, according to one implementation of the present invention.
Figure 3: shows an arrangement of different arc absorber layers, according to second implementation of the present invention.
Figure 4: shows a detailed arrangement of 2nd and 4tharc absorber layer, according to second implementation of the present invention.
Figure 5: shows an arc absorber placed at the end of the arc duct path of series of coupled gas insulated switchgear panels.

Figure 6: shows the series of coupled gas insulated switchgear panels in which arc absorbers are placed at each ends.
Figure 7: shows the series of coupled gas insulated switchgear panels in which arc absorbers are placed at both ends and at the common junction of middle switchgears.
Figure 8: shows the series of coupled gas insulated switchgear panels in which arc absorbers are placed at both ends and at every junction of switchgear.
It may be noted that the one or more elements may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding of the embodiments of the present disclosure, so as not to obscure the drawings with details that will be readily apparent to those of ordinary skilled in the art having benefit of the description herein.
DETAILED DESCRIPTION OF THE INVENTION
It should be understood at the outset that although illustrative implementations of the present disclosure are detailed below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present disclosure should be in no way be construed as being limited to the illustrative implementations, drawings, and techniques, illustrated below, including the exemplary design and implementation illustrated and described herein, but may be modified within the scope of equivalents.
Unless otherwise defined, all terms and especially technical and/or scientific terms, used herein, may be taken to have the same meaning as commonly understood by one ordinarily skilled in the art.

Reference is made herein to some "embodiments". An embodiment is an example of a possible implementation of any features and/or elements presented in the claims. Some embodiments have been described for the purpose of illuminating one or more potential ways in which the specific features and/or elements of the foregoing claims fulfill the requirements of uniqueness, utility, and non-obviousness.
The present subject matter described herein, in general, relates to developing arc absorber/diffuser in a gas insulated switchgear which results in releasing hot gases inside the room ensuring safety is very crucial.
In one and second implementations, the parts and components as illustrated in the figures are listed as under:
1. Arc Duct
2. SMC Sheet
3. Perforated Sheet metal of different thickness and Diameter.
4. Pressure relief Flaps.
5. Wire Mesh.
Reference is made to the figure 1, which shows the flow of hot gases from faulted compartment to arc duct.
Due to Internal Arc Fault, rapid pressure rise, and temperature rise occurs in the faulted compartment. Due to this, the kinetic energy of the gas in increased which ultimately puts mechanical stresses on the compartment. Hence to ensure the release of these gas in same room with safety, it is important to reduce the kinetic energy and also temperature the gas before its release.
In one implementation, reference is made to the figure 2 which shows the arc diffuser arrangement on top of arc duct. In the implementation, both reduction in

kinetic energy of gas and also the temperature is achieved by the arc diffuser which is made of perforated sheet metal box. This box consists of layers of perforated sheet metals. In each layer, perforations of different diameters are given. If the box consists of 5 layers, then the 1st layer has perforations of 2mm diameter, 2nd layer has 1.5mm diameter, 3rd has 0.5mm diameter, 4th layer has 1.5mm diameter and the last layer again has 2 mm diameter. This is done to converge and diverge the hot gases. The no. of layers can be increased depending upon the fault rating. All these layers are stacked together and assembled in the box whose bottom side is covered by the sheet moulding compound (SMC) sheet. The whole assembly is installed at the top of the Arc Duct.
Whenever an internal arc fault occurs, pressure and temperature rise will result into opening of pressure relief flaps and now the gas enters the arc duct. These hot gases having high velocity hits the SMC sheet and enters the perforated box horizontally. Thus, the SMC sheet performs the function of decreasing the kinetic energy of gas by creating turbulence and also cools down the gas by absorbing heat. After the gases enters the Box, they are again cooled down by perforated sheet metal layers of different diameters. Due to converging and diverging of the hot Gas again the velocity of the gas is reduced and is channeled in proper direction and released into the room.
In second implementation, both reduction in kinetic energy of gas and also the temperature is achieved by arc absorber which is made of 4 layered perforated sheet metal box which is shown in figure3. However, the number of layers of the perforated sheet metal box are not limited to 4. The 4 different layers are surrounded by side plates which strengthens and packs all the 4 layers. The whole assembly can be installed at the top of the Arc Duct. The 1st layer is the bottom most layer, consist of perforated sheet metals. Whenever hot gases enter the Arc duct, the 1st layer provides friction and turbulence to the high velocity Gases. After the reduction in kinetic energy, the gas enters the 2nd layer. This layer is assembly total 5 independent layers which is shown in the figure4. 2 packing

sheet layers having perforations are assembled at the top and bottom. Between these2 layer three thin sheets of 1 mm thickness with 3mm diameter holes or a simple wire-mesh of 1 mm diameter is sandwiched. The layer serves a heat exchanger, the thin sheets or wire mesh are allowed to absorb heat from the gases in a controlled fashion. From this layer, the gas enters the 3rd layer. This layer is basically a honeycomb-like structure having thickness of 5mm. When the gas enters this layer, kinetic energy of the gases pretty much under control and hence in this layer large amount of heat absorption takes place. Glow particles are also trapped in this region. After this layer, gases enters the 4th layer which is similar to the 2nd layer, it may be of different thickness depending upon the fault rating. Apart from the function served by the 2nd layer, this layer also channels gases in proper direction before it is released in the room.
This arc absorber arrangement can also be used when there is a series of coupled gas insulated switchgear panels. Suppose there are four gas insulated switchgear panels coupled with one another. We can have various combinations of numbers of absorbers. These absorbers are fitted in the arc duct paths such that the heat and kinetic energy of exhaust gas gets absorbed. Figure 6, figure 7, figure 8 shows various arrangements of arc absorbers in coupled gas insulated switchgear panels.
Some of the non-limiting advantages of the present invention are as follows:
• Cools down the hot gases and releases in the same room and hence ecological.
• Increased reliability of product.
• Easy Access which makes the assembly simple.
• One to One Replacement Possible of the arc absorber/diffuser.
• Low coststructure.
• It is easily expandable/ Upgradable with minimum required space.

Those skilled in the art will recognize other use cases, improvements, and modification to the embodiments of the present disclosure. All such improvements and other use-cases are considered within the scope of the concepts disclosed herein.

WE CLAIM ;

1. An arc absorber for at least a switchgear unit, wherein said arc absorber
comprising:
At least a four layered perforated sheet metal box;
Characterized in that, said four layered perforated sheet metal box
includes:
a first layer of said four layered perforated sheet metal box having
at least a perforated sheet metal where hot gas enters through an air
duct;
a second layer of said four layered perforated sheet metal box is an
assembly of at least five independent layers;
a third layer of said four layered perforated sheet metal box where
gas enters from said second layer, wherein said third layer having a
honey comb-like structure where large amount of heat absorption
of said hot gas takes place; and
a fourth layer having a structure similar to said second layer,
wherein said fourth layer allows channeling of gases in a direction
before releasing said gases.
2. The arc absorber as claimed in claim 1, wherein said five independent
layers of said second layer further comprises:
at least two packing sheet layers having plurality of perforations assembled at a top and at a bottom, wherein said layer serves a heat exchanger.
3. The arc absorber as claimed in claim 2, wherein said second layer
comprises a thin sheet layer sandwiched between said two packing sheet
layer, which allows to absorb heat from said hot gases, which allows to
absorb heat from said hot gases.

4. The arc absorber as claimed in claim 3, said thin sheets having a thickness of 1-2 mm with a diameter of 3-4mm holes or a simple wire-mesh of 1-2 mm diameter.
5 5. The arc absorber as claimed in claim 1, wherein said third layer having
thickness of 5-6mm.
6. An arc diffuser comprising a perforated sheet metal box, wherein said box
comprising at least five layered structure stacked together to converge and
) diverge the hot gases,
wherein, a first layer of said five layers includes a plurality of perforations
of at least a 2mm diameter;
a second layer of said five layers having a plurality of perforations of at
least a 1.5mm diameter;
5 a third layer of said five layers having a plurality of perforations of at least
a 0.5mm diameter;
a fourth layer of said five layers having a plurality of perforations of at
least a 1.5mm diameter; and the last layer again having a plurality of
perforations of at least a 2 mm diameter.