Description:TECHNICAL FIELD
[0001] The present disclosure relates to an earth switch assembly used in medium voltage air insulated switchgear. More particularly, the present disclosure relates to an earth switch assembly for an air insulated switchgear.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] The Air Insulated Switchgear acts as a protection for other electrical equipment’s. The Air Insulated Switchgear is installed ahead of other vulnerable electrical equipment’s in the transmission phase of supply. During the event of any malfunction in the transmission line, the air insulated switchgear trip opens a vacuum interrupter that helps to isolate healthy parts from faulty parts of a transmission line. The air insulated switchgear may require maintenance and may be temporarily tuned off. The main supply of the switchgear is turned off and may include residual charges left on a cable and a busbar of the air insulated switchgear. To remove these residual charges from the cables or the busbar an earth switch assembly may be utilized. Before operating the air insulated switchgear, the earth switch assembly is operated to earth all the residual charges from the cable.
[0004] Further, during a preventive maintenance procedure, the earth switch assembly is operated to earth either the cable or the busbar. The earth switch assembly for the cable and busbar may include an operating mechanism for independent operation of the cable and the busbar respectively. During the operation of the earthing switch assembly, a spark, an arc, and a residual gas may be produced that may be hazardous to a personnel operating the earth switch assembly.
[0005] Conventionally, an earth switch assembly operates with dielectric medium filled with air. The dielectric strength of air is approximately 3 kilovolts per millimeter (kV/mm). The earth switch assembly operating with air may provide a phase to phase and a phase to earth clearance depending upon a voltage rating. The earth switch assembly operated in air may also generate sparks/arcs during earthing which may pose an occupational hazard. Further, the sparks generated during earthing may damage the other components depending upon the severity of intensity of the arc, which is undesirable.
[0006] US7122758 relates to a field of high voltage technology, in particular to an electrical insulation and connection technology for gas insulated switchgear assemblies (GIS) at ground potential. It is based on an earthing switching device and a gas insulated switch-gear assembly. However, US7122758 does not describe protection for medium voltage air insulated switchgear as described in the present disclosure.
[0007] US629235 describes a gas insulation switch suitable for earth anti-warming measures. However, US629235 does not describe an earth switch assembly used in medium voltage air insulated switchgear.
[0008] US6995330 describes an earthing switch having a very short switching time due to a spring control mechanism that avoids formation of electrical arcs. However, US6995330 does not describe an earth switch assembly used in medium voltage air insulated switchgear.
[0009] There is, therefore, a need in the art to provide a system and a method that can mitigate the problems associated with the prior arts.

OBJECTS OF THE INVENTION
[0010] Some of the objects of the present disclosure, which at least one embodiment herein satisfy are as listed herein below.
[0011] It is an object of the present disclosure to provide an earth switch assembly, in which a phase to phase and a phase to earth distance is reduced.
[0012] It is an object of the present disclosure to provide an earth switch assembly, which requires a lesser space to mount the earth switch.
[0013] It is an object of the present disclosure to provide an earth switch assembly, in which sparking or arcing observed during earthing is reduced.
[0014] It is an object of the present disclosure to provide an earth switch assembly that requires less maintenance.
[0015] It is an object of the present disclosure to provide an earth switch assembly where a sulphur hexafluoride (SF6) gas acts as an arc sequence medium and enhances the safety as well as product performance.
[0016] It is an object of the present disclosure to provide an earth switch assembly where an interlock ensures that the earth switch may be operated only when the amount of SF6 required is present in a chamber containing the earth switch.
[0017] It is an object of the present disclosure to provide an earth switch assembly that reduces arc production significantly.

SUMMARY
[0018] This section is provided to introduce certain objects and aspects of the present disclosure in a simplified form that are further described below in the detailed description. This summary is not intended to identify the key features or the scope of the claimed subject matter.
[0019] The present disclosure relates to the earth switch assembly used in medium voltage air insulated switchgear, and more particularly, the present disclosure relates to increasing dielectric performance phase to phase, and phase to earth of the earth switch.
[0020] In an aspect, the present disclosure relates to an earth switch assembly for an air insulated switchgear. Then earth switch assembly may include an earth switch. Further the earth switch assembly may include a chamber configured in the earth switch. The chamber may be filled with a sulphur hexafluoride (SF6) gas. A pressure regulator may be operatively coupled to the chamber for maintaining the SF6 gas pressure inside the chamber to a pre-defined level.
[0021] In an embodiment, a main shaft may be operatively coupled with the earth switch to generate an interlock with a front face of the earth switch when the SF6 gas pressure inside the chamber is at the pre-defined level.
[0022] In an embodiment, the interlock between the main shaft and the front face of the earth switch may indicate a service condition of the earth switch assembly.
[0023] In an embodiment, an operating shaft may be slidably configured with the main shaft to operate the main shaft and provide the service condition of the earth switch assembly.
[0024] In an embodiment, one or more earth switch blades may be configured in the earth switch and may be operably coupled with the main shaft.
[0025] In an embodiment, the main shaft may be configured to switch the one or more earth switch blades and operate the earth switch assembly to a test condition.
[0026] In an embodiment, the earth switch may be utilized for a gas insulated switchgear and an air insulated switchgear.
[0027] In an embodiment, the pressure regulator may be a manometer configured with the earth switch to indicate the SF6 gas pressure.
[0028] In an embodiment, the main shaft may be maneuvered to achieve a desired interlock with the earth switch assembly.

BRIEF DESCRIPTION OF DRAWINGS
[0029] The accompanying drawings, which are incorporated herein, and constitute a part of this disclosure, illustrate exemplary embodiments of the disclosed methods and systems which like reference numerals refer to the same parts throughout the different drawings. Components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Some drawings may indicate the components using block diagrams and may not represent the internal circuitry of each component. It will be appreciated by those skilled in the art that disclosure of such drawings includes the disclosure of electrical components, electronic components, or circuitry commonly used to implement such components.
[0030] FIGs. 1A-1C illustrate an exemplary representation of earth switch assembly, in accordance with an embodiment of the present disclosure.
[0031] FIGs. 2A-2B illustrate an exemplary representation of an earth switch, in accordance with an embodiment of the present disclosure.

BRIEF DESCRIPTION OF THE INVENTION
[0032] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address all of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein.
[0033] The ensuing description provides exemplary embodiments only and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the disclosure as set forth.
[0034] Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail to avoid obscuring the embodiments.
[0035] Also, it is noted that individual embodiments may be described as a process that is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed but could have additional steps not included in a figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination can correspond to a return of the function to the calling function or the main function.
[0036] The word “exemplary” and/or “demonstrative” is used herein to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as “exemplary” and/or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes,” “has,” “contains,” and other similar words are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising” as an open transition word without precluding any additional or other elements.
[0037] Reference throughout this specification to “one embodiment” or “an embodiment” or “an instance” or “one instance” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0038] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
[0039] The various embodiments throughout the disclosure will be explained in more detail with reference to FIGs. 1A TO 2B.
[0040] FIGs. 1A-1C illustrates an exemplary representation of earth switch assembly, in accordance with an embodiment of the present disclosure.
[0041] As illustrated in FIG. 1A, an earth switch assembly 100 may be provided for an air insulated switchgear. The earth switch assembly 100 may include an earth switch 102. A chamber 104 may be configured in the earth switch 102. The chamber 104 may be filled with a sulphur hexafluoride (SF6) gas. The SF6 gas may increase a dielectric performance of the earth switch 102 in the air insulated switchgear. A pressure regulator 106 may be operatively coupled to the chamber 104 for maintaining the SF6 gas pressure inside the chamber 104 to a pre-defined level. The air insulated switchgear may either be tripped during a fault condition or tripped by a maintenance personnel during a maintenance drive.
[0042] In an embodiment, an earth switch operating access flap may be removed and operated with a handle. Operating the earth switch 102 may facilitate one or more earth switch blades 112 to connect with an earth switch arcing contact 114 configured in the earth switch assembly 100. After a completion of maintenance, the earth switch 102 may be operated to remove or disengage the one or more earth switch blades 112 from the earth switch arcing contact 114 and the air insulated switchgear may be ready to operate again.
[0043] In an embodiment, the one or more earth switch blades 112 may be operated between an earth position and an off position. When the earth switch assembly 100 is in a service condition, the earth switch 102 may be in ‘off’ position. To operate the earth switch 102, the air insulated switchgear may in tripped condition and must move to a test/isolated condition. The main shaft 108 may be operatively coupled with the earth switch 102 may be used to generate an interlock with a front face of the earth switch 102 when the SF6 gas pressure inside the chamber 104 is at a pre-defined level. The interlock between the main shaft 108 and the front face of the earth switch 102 indicates a service condition of the earth switch assembly 100.
[0044] In an embodiment, an operating shaft 110 may be slidably configured with the main shaft 108 to operate the main shaft 108 and provide the service condition of the earth switch assembly 100. Further, the main shaft 108 may be configured to switch the one or more earth switch blades 112 and operate the earth switch assembly 100 to a test condition.
[0045] FIGs. 2A-2B illustrate an exemplary representation of an earth switch, in accordance with an embodiment of the present disclosure.
[0046] In an embodiment, an operating shaft 110 of the earth switch102 may be accessible, through an opening, outside the chamber 102 for operating the one or more earth switch blades 112. The operating shaft 110 may be configured to switch the one or more earth switch blades 112 between a service condition and a test condition. The pressure regulator 106 may be configured to continuously measure the SF6 gas pressure and may generate an indicative alarm if the (SF6) gas pressure drops below a predefined pressure. The interlock may prevent operation of the earth switch 102 within the chamber 104 if the SF6 gas pressure is below the predefined pressure. The interlock may prevent operation of the earth switch 102 within the chamber 104 if the SF6 gas pressure is below the predefined pressure. In an embodiment, the maintenance personnel may use a handle with proper leverage to operate the earth switch 102. The operating shaft 110 may be rotated in a clockwise direction. The operating shaft 110 may be connected with the main shaft 108 through one or more linkages. The main shaft 108 may transfer energy to a plurality of switch springs 116 configured in the earth switch assembly 100.
[0047] The plurality of switch springs 116 may compress and store the energy and may further toggle after a certain amount of energy is acquired. The plurality of switch springs 116 may release the energy to the one or more earth switch blades 112 and may move earth switch 102 from the ‘Off’ position to the ‘Earth’ position. The one or more earth switch blades 112 may slide over and connect with earth switch arcing contact 114. The residual charges present in a conductor (cable side) 1 may be drained out through the earth switch 102. The earth switch arcing contact 114 may be connected with an earth bar of a substation. Upon a failure of the interlock, the earth switch 102 may be capable to withstand the desired short circuit current and redirect the current through an earth bar.
[0048] In an embodiment, the dielectric strength of SF6 may be almost 2.5 times better than air. As the earth switch 102 is assembled within the SF6 compartment, the phase to phase and phase to earth distance may be reduced. Lesser space may be required to mount the earth switch 102 of similar enclosure frame or rating. Also the sparking or arcing generated during earthing may be reduced considerably.
[0049] Further, in an embodiment, the earth switch assembly 100 arrangement may enable an inlet and outlet of the SF6 gas during manufacturing and a periodic maintenance procedure. The main shaft 108 may indicate a physical situation (ON or EARTH) as an indicator and may be maneuvered achieve a desired interlock with the earth switch assembly 100.
[0050] While considerable emphasis has been placed herein on the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be implemented merely as illustrative of the disclosure and not as a limitation.

ADVANTAGES OF THE INVENTION
[0051] The present disclosure provides an earth switch assembly, in which a phase to phase and a phase to earth distance is reduced.
[0052] The present disclosure provides an earth switch assembly, which requires a lesser space to mount the earth switch.
[0053] The present disclosure provides an earth switch assembly, in which sparking or arcing observed during earthing is reduced.
[0054] The present disclosure provides an earth switch assembly that requires less maintenance.
[0055] The present disclosure provides an earth switch assembly where a sulphur hexafluoride (SF6) gas acts as an arc sequence medium and enhances the safety as well as product performance.
[0056] The present disclosure provides an earth switch assembly where an interlock ensures that the earth switch may be operated only when the amount of SF6 required is present in a chamber containing the earth switch.
[0057] The present disclosure provides an earth switch assembly that reduces arc production significantly.

  , Claims:1. An earth switch assembly 100 for an air insulated switchgear, the earth switch assembly 100 comprising:
an earth switch 102;
a chamber 104 configured in the earth switch 102, wherein the chamber 104 is filled with a sulphur hexafluoride (SF6) gas; and
a pressure regulator 106 operatively coupled to the chamber 104 for maintaining the SF6 gas pressure inside the chamber 104 to a pre-defined level.
2. The earth switch assembly 100 as claimed in claim 1, wherein a main shaft 108 operatively coupled with the earth switch 102 is used to generate an interlock with a front face of the earth switch 102 when the SF6 gas pressure inside the chamber 104 is at the pre-defined level.
3. The earth switch assembly 100 as claimed in claim 2, wherein the interlock between the main shaft 108 and the front face of the earth switch 102 indicates a service condition of the earth switch assembly 100.
4. The earth switch assembly 100 as claimed in claim 3, wherein an operating shaft 110 is slidably configured with the main shaft 108 to operate the main shaft 108 and provide the service condition of the earth switch assembly 100.
5. The earth switch assembly 100 as claimed in claim 2, wherein one or more earth switch blades 112 are configured in the earth switch 102 and are operably coupled with the main shaft 108.
6. The earth switch assembly 100 as claimed in claim 5, wherein the main shaft 108 is configured to switch the one or more earth switch blades 112 and operate the earth switch assembly 100 to a test condition.
7. The earth switch assembly 100 as claimed in claim 1, wherein the earth switch 102 is utilized for a gas insulated switchgear and an air insulated switchgear.
8. The earth switch assembly 100 as claimed in claim 1, wherein the pressure regulator 106 is a manometer configured with the earth switch 102 to indicate the SF6 gas pressure.
9. The earth switch assembly 100 as claimed in claim 2, wherein the main shaft 108 is maneuvered to achieve a desired interlock with the earth switch assembly 100.