TECHNICAL FIELD
[001] The present disclosure, in general, relates to Gas-insulated high voltage
switchgear (GIS) which is a metal encapsulated switchgear comprising of high-voltage components such as circuit-breakers and disconnectors, which control, protect and isolate electrical equipment whenever required and can be safely operated in confined spaces. In particular, the present disclosure provides a single-phase disconnector switch (DS) along with earthing switch (ES) in a single enclosure, which helps in optimizing bay width of gas-insulated switchgear (GIS) bay.
BACKGROUND
[002] Background description includes information that ma y 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.
[003] The present disclosure pertains to gas-insulated switchgear that plays a
major role in breaking current in the event of an accident such as grounding or short circuit in the transmission/transmission system or electric circuit.
[004] In general, electricity having a voltage of about 20,000 V in a power
plant is boosted to an ultra-high voltage suitable for power transmission a nd transmitted to a primary substation, where the supplied voltage drops to 22,900 V to the secondary substation and after that supplied to each customer.
[005] The power from the secondary substation is supplied to the receiving
facility of each customer through a distribution system composed of overhead distribution lines and underground distribution lines and is supplied to the low voltage consumer side through various outdoor transformers.

[006] Disconnector switch (DS) and earthing switch modules are also important
modules of gas-insulated metal-clad switchgear equipment. A disconnector switch (DS) is provided to isolate/disconnect the parts of gas-insulated high voltage sections. DS is also employed in a system to interrupt/ make capacitive currents in the system. An insulating element is connected between the movable contact and drive system to have isolation for the drive system from high voltage.
[007] A gas-insulated earthing switch (ES) is normally provided in gas-
insulated switchgear (GIS) to discharge remnant DC charge on long lines/cables. Under normal working conditions, the earthing switch remains in open condition. During the maintenance a nd shut down period, the live parts/section of a substation are grounded through the earthing switches to ensure the safety of the maintenance personnel.
[008] The ES within GIS is also used as the return path during
calibration/accuracy assessment of a current transformer. The ES also interrupts and makes electro-magnetically and electro-statically induced currents. The ES is provided with a movable contact to connect the components of the high voltage section of the Gas-insulated switch to the ground. The moving contact is connected to the ground through a current collector. An insulating spacer is provided between the metallic enclosure and ground terminal to make the metallic enclosure potential free during the discharge of trapped charges to the ground.
[009] In conventional gas-insulated switchgear, these modules are generally
provided as independent modules, or both the modules are operated by the same drive. Support epoxy insulators are provided for the contact system as well as the connection extends to the other modules in the GIS bay configurations. For this, the HT terminals and the contact system of DS and ES are connected on the spherical adapter and it is supported with the help of the epoxy insulators.
[010] In one of the prior arts, a 3-position switch is disclosed that prevents the
generation of foreign objects by maximally suppressing a sliding frictional force between the moving contact and the hollow conductor while adopting a simple

[011] mechanism to rectilinearly move both the moving contact of the
disconnection portion and the moving contact of the earthing switch portion in an interlocking manner, thereby reducing the size of the entire apparatus including an operating device as shown in Fig. 1(a) to 1 (c)). Another set of the prior art also explained a similar arrangement.
[012] The biggest drawback associated with all the above-mentioned
arrangements is that they cannot be used for high voltage applications as different speeds are required for the operation of the disconnector and earthing switches. Further, the system becomes bulky fo r higher stroke lengths of the disconnector and earthing switches.
[013] One of the other prior art proposes the disconnector switch for use in a
multi-pole section of a metal-clad, gas-insulated, high-voltage switchgear with each of the poles located within an enclosed housing terminating in two end faces with two feed through insulators and having two conductors passing through said feed through insulators.
[014] In another prior art, multiple epoxy insulators are used to support the
contact system of the disconnector switch as shown in Fig.2. Further, the contact system is made in angular orientation, which in turn increases the complexity of manufacturing.
[015] In most of the above-mentioned prior arts, commonly insulating
spacers/epoxy insulators are used to support the conductor assemblies and for extending the connection to the other modules. The said conventional epoxy support insulators increase the overall size and cost of the system. Moreover, the rejection rate of these insulators is also quite high. In addition, GIS bay width also increases with epoxy support insulators. Furthermore, t he cost of these insulators is very high. These all things need to be addressed for making the system and cost-effective.
[016] Hence, there is a need to develop a design of Gas-insulated switchgear in
which the dis-connector switch and the earthing switch are arranged in common enclosure/housing with few insulators support fo r conductor/contact assembly

instead of bulky cone or disc epoxy insulators. Precisely, the present disclosure focuses on reducing cost, size of the module, and GIS bay width.
[017] It is, therefore, desirable to provide a structure of the gas-insulated
switchgear that overcomes prior art problems, to help in reducing cost, size of the module, and GIS bay width.
OBJECTS OF THE DISCLOSURE
[018] Some of the objects of the present disclosure, which at least one
embodiment herein satisfy, are listed here in below.
[019] It is a general or primary object of the present disclosure to propose a
single common housing in gas-insulated switchgear for accommodating the dis-connector and earthing switch.
[020] It is yet another object of the present disclosure to provide a multi-port
spherical connector to accommodate moving contact assembly of the dis-connector switch as well as fixed contact assembly of earthing switch effectively.
[021] It is a further object of the present disclosure to propose a multi-port
spherical connector with self-contained shields.
[022] It is further another object of the present disclosure to propose orientation
of disconnector switch and earthing switch in such a way that the design of disconnector cum earthing switch to be achieved.
[023] It is another object of the present disclosure to simplify the operation of
the switches and ease assembly.
[024] It is another object of the present disclosure to provide a FRP insulated
support instead of bulky and costly epoxy insulators.
[025] It is another object of the present disclosure is to propose a highly
efficient FRP insulated support attached to the spherical connector of gas-insulated switchgear.

[026] It is another object of the present disclosure to provide a spherical
enclosure with limited ports and dimensions for the accommodation of disconnector and earthing switch modules.
[027] It is another object of the present disclosure to provide a spherical
enclosure fo r disconnector cum earthing switch with a support insulator made of insulating materials.
[028] It is another object of the present disclosure to propose a spherical
enclosure for disconnector cum earthing switch to achieve the lowest possible bay width of gas-insulated switchgear.
[029] It is another object of the present disclosure to provide a disconnector
cum earthing switch with a minimum number of epoxy insulators for supporting contact assembly.
[030] It is another object of the present disclosure to propose an insulator with
the lowest possible discharge/radial distance.
[031] It is another object of the present disclosure to propose a FRP insulator
without additional high voltage or grounded metallic shields.
[032] It is another object of the present disclosure to propose a FRP insulator
such that the mechanical strength of the insulator is ensured by using appropriate gluing or casted techniques.
[033] These and other objects and advantages will become more apparent when
reference is made to the following description and accompanying drawings.
SUMMARY
[034] This summary is provided to introduce concepts related to a single
enclosure accommodating single phase dis-connector switch (DS) along with earthing switch (ES) in a single enclosure, which helps in optimizing bay width in gas-insulated switchgear (GIS) bay. The concepts are further described below in the detailed description. This summary is not intended to identify key features

or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[035] In an embodiment, the present disclosure provides an assembly for
incorporating a disconnector switch and an earthing switch in a single enclosure of gas-insulated switchgear comprising a spherical grounded enclosure having multiple ports for incorporating a FRP insulator of a tubular structure, wherein the first end of the tubular structure is connected to the spherical grounded enclosure and the second end is connected to the spherical connector.
[036] In an aspect, the present disclosure provides the spherical grounded
enclosure having multiple ports in which two insulator ports are used fo r fixing epoxy insulators and two drive ports are used fo r fixing drive systems for DS and ES.
[037] In an aspect, the present disclosure provides the assembly in which the
two insulator ports and two drive ports provided on the spherical connector are placed at 180 degrees to one another.
[038] In an aspect, the present disclosure provides the assembly in which the
two drive ports fo r drive systems and the insulator ports for epoxy insulators are at 90 or 270 degrees to one another.
[039] In an aspect, the present disclosure provides the assembly in which the
spherical grounded enclosure also consists of four ports suitable fo r installing the sensor for determining gas pressure, viewing port, rupture disk fo r protecting the system against gas pressure rise, molecular sieve for protecting the system against moisture.
[040] In an aspect, the present disclosure provides the assembly in which the
tubular structure of the insulator is made of FRP or Kevlar or equivalent material.
[041] In an aspect, the present disclosure provides the assembly in which the
first end of the tubular structure of the insulator is connected to a ground terminal and then to the spherical grounded enclosure.

[042] In an aspect, the present disclosure provides the assembly in which the
second end of the tubular structure of the insulator is connected to a high voltage terminal and then to the spherical connector.
[043] In an aspect, the present disclosure provides the assembly in which the
high voltage terminal and tubular structure of the insulator are fixed through gluing, and similarly, the grounded terminal and tubular structure are also fixed through gluing.
[044] In an aspect, the present disclosure provides the assembly in which the
HT and grounded terminal of the tubular structure of the insulator are fixed in such a way that the lowest possible radial /discharge distance, “D” can be achieved and sufficient gluing length of these terminals can be ensured.
[045] In an aspect, the present disclosure provides the assembly in which the
mechanical strength of the insulator is ensured by using appropriate gluing or casted techniques.
[046] Various objects, features, aspects, and advantages of the inventive subject
matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[047] The illustrated embodiments of the subject matter will be best understood
by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, a nd methods that are consistent with the subject matter as claimed herein, wherein:
[048] FIG.1(a)-1(c) illustrates conventional gas-insulated switchgear, with
disconnector and earthing switch, in combination in accordance with the prior art.

[049] FIG.2 illustrates a conventional gas-insulated disconnector switch with
multiple epoxy insulators, in accordance with the prior art.
[050] FIG.3(a) illustrates the disconnector switch as an independent module in
accordance with the prior art.
[051] FIG.3(b) illustrates the earthing switch as an independent module in
accordance with the prior art.
[052] FIG.4(a) illustrates the 3D view of a single spherical grounded enclosure
that establishes the integration between the Disconnector switch and Earthing switch in accordance with the prior art.
[053] FIG.4(b) illustrates the 3D view of three spherical grounded enclosure
that establishes the Integration between the Disconnector switch a nd Earthing switch in accordance with the prior art.
[054] FIG.5 illustrates the 3D view of the six-port spherical connector placed
inside the spherical grounded enclosure and various connections in accordance with the prior art.
[055] FIG.6(a) illustrates the line diagram (front view) showing the integration
between the Disconnector switch and Earthing switch in accordance with the prior art.
[056] FIG.6 (b) illustrates the line diagram (top view) showing the integration
between the Disconnector switch and Earthing switch in accordance with the prior art.
[057] FIG.7(a) illustrates the line diagram showing the interconnection between
the insulator with Spherical connector assembly placed inside the spherical grounded enclosure in accordance with the embodiment of the present disclosure.

[058] FIG.7(b) illustrates the line diagram showing the enlarged view of the
integration of the insulator with Spherical connector assembly in accordance with the embodiment of the present disclosure.
[059] FIG.8(a) illustrates the line diagram showing the interconnection between
the Disconnector Switch with Insulator in accordance with the embodiment of the present disclosure.
[060] FIG.8(b) illustrates the line diagram showing the interconnection between
the Earthing Switch with Insulator in accordance with the embodiment of the present disclosure.
[061] FIG.9 illustrates the 3D view of three grounded metallic enclosures for
establishing the interconnection between the disconnector and earthing switch with the insulator in accordance with the embodiment of the present disclosure.
DETAILED DESCRIPTION
[062] The following is a detailed description of embodiments of the disclosure
depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[063] As used in the description herein and throughout the claims that follow,
the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[064] FIG.3(a) and FIG.3(b) illustrate the disconnector switch and earthing
switch module assembly as independent modules in accordance with the prior art.

[065] In accordance with Fig.3(a), the disconnector switch comprises a
spherical grounded enclosure [16] having a spherical connector [01] with multiple ports for accommodating the epoxy insulator [08A], dish cover [36], and DS drive housing [30].
[066] In accordance with Fig.3(b), the earthing switch comprises a spherical
grounded enclosure [16] having a spherical connector [01] with multiple ports fo r accommodating the epoxy insulator [08B,08C], current transfer flange [20], and ES drive housing [31].
[067] FIG.4(a) illustrates the 3D view of a single spherical grounded enclosure
that establishes the integration between the Disconnector switch and Earthing switch in accordance with the prior art.
[068] Here, the spherical grounded enclosure [16] with spherical connector is
shown comprising of two insulator ports [16D,16E] in 90 or 270 degrees for fixing of epoxy insulators [08A,08B] and two drive ports [16F,16G] for fixing drive systems for DS a nd ES. The ports [16F, 16G] for drive systems are exactly at 180 degrees to the epoxy insulators [08A,08B] ports [16D,16E]. The spherical grounded enclosure [16] also comprises of minimum four ports [33] suitable for gas filling and sensor [33A], viewing port [33B], protection system against gas pressure rise (rupture disk) [33C], protection against moisture (molecular sieve) [33D], etc. The said spherical-shaped universal connector [01] having a configuration that meets all connection requirements of metal-clad gas insulated substation equipment.
[069] Fig.4(b) illustrates the 3D view of the three spherical grounded enclosure
that establishes the integration between the disconnector switch and the earthing switch in accordance with the prior art.
[070] Fig.5 illustrates the configuration of the spherical connector and the
connection establish through it.
[071] The proposed spherical connector [01] acts as housing. It has six ports
provided at the top, bottom, left, right, front and back. It provides a low resistance path with controlled electrical stress around its geometry. The first

port (01B) of the spherical connector [01] is connected to ES fixed contact [17] and ES fixed contact shield [17A]. Precisely, the ES fixed contact [17] is surrounded by fixed contact (FC) shield [17A]. The second port (01C) is connected to DS current collector [02] and DS Moving contact shield [03]. Precisely, the DS Current collector [02] is surrounded by a moving contact (MC) shield [03].
[072] The DS current collector [02] also acts as a stopper for the disconnector
switch during its closing operation. The third port is connected to the stopper cum shield [06]. The stopper cum shield [06] has a provision of stopper arrangement to avoid overrun of disconnector switch during the opening operation. This profile of stopper cum shield [06] ensures a uniform electric field across the insulated operating rod [05] (shown in Fig.5(a)). The fourth port has a self-contained shield [01A] that are used for the terminals which are not used for extending high voltage connection. The fifth (01D) and sixth (01E) port are connected to HT terminals of epoxy insulators [08B, 08C].
[073] Specifically, the Spherical connector [01] is a unique component
designed to cater to multiple requirements in switchgear equipment to accommodate disconnector Switch (DS) and earthing Switch (ES) connections. The objective of the connector [01] is to transfer current from one module of the switchgear/power equipment to another module. It is also used to commensurate electric stress relieved connection in different orientations like “L”, “T” or 00-900 of any orientation.
[074] FIG.6(a) illustrates the front view showing the connection between the
spherical connector and the Disconnector switch along with the Earthing Switch in a spherical grounded enclosure.
[075] The various components of the disconnector switch are attached to the
first axis and shown in the upper section of the figure. The DS fixed contact [07] of the disconnector switch (DS) is held on an epoxy insulator [08] with a suitable DS adapter [09] and adapter shield [10]. The DS fixed contact [07] is made of a high conductivity material with low erosion refractory material tip. The DS fixed

contact [07] is covered by a DS fixed contact shield [11] with designed axial and annular space to control the axial field between the fixed and moving contacts.
[076] The DS moving arcing contact [04] placed above the DS fixed contact is
surrounded by a DS moving contact shield [03] when DS is in fully open condition. The DS moving arcing contact [04] is located in housing called a Spherical connector [01].
[077] The proposed spherical connector [01] can also act as a guide to the DS
insulating operating rod [05] that is used for the operation of DS moving arcing contact [04]. The proposed spherical connector [01], acts as a DS current transfer connector, i.e., transfers current from DS movable arcing contact [04] to the module connected to the switching element through DS current collector [02].
[078] Mainly, the DS current collector [02] is used to extend dynamic current
transfer during the travel of movable contact. The DS current collector [02] extends the dynamic current transfer of discharge/arcing current of HV sections from DS fixed contact [07] to DS movable arcing contact [04] to spherical connector [01] when the movable contact is about to make contact with fixed contact (during pre-arcing time). The fixed contact [09] and moving arcing contact [04] are integrated to shield to protect the high voltage system from secondary breakdown.
[079] The DS LT shield [12] is also provided on the spherical grounded
enclosure [16] to limit higher electrostatic fields around the grounded terminal of the insulated operating rod [05]. The DS drive system [13,14,15] provides the energy required fo r the operation of the DS movable contact system. The DS operation is achieved by using moving arcing contact [04] and insulating operating rod [05] which on another side is attached to the DS drive system [13,14,15] which consists of an operating link [13], lever arrangement [14], a nd shaft arrangement[15]. The entire contact system is insulated from the spherical grounded enclosure [16] with designed SF6 gas density. The DS moving contact shield [03] is separated from the DS fixed contact shield [11] by a distance ‘D’ proportional to the system voltage and the SF6 gas density.

[080] In another axis (45 to 135 degrees), preferably 900 to the first axis,
various components of the earthing switch are attached. Moreover, the various components of the earthing switch are shown in the below portion of Fig.
[081] The ES fixed contact [17] is also fixed on a spherical connector [01]. The
ES moving arcing contact [18] is plugged into ES fixed contact [17] when the earthing switch is in close condition. The ES fixed contact [17] is surrounded by fixed contact (FC) shield [17A].
[082] The orientation of placement of ES moving arcing contact [18] and DS
moving arcing contact [02] is 45˚ to 135˚ each other. An ES current collector [19] is used to extend dynamic current transfer during the travel of movable contact. The ES current collector [19] extends the dynamic current transfer of discharge/arcing current of HV sections from ES fixed contact [07] to ES movable arcing contact [18] to current transfer flange [20] when the ES movable arcing contact [18] is about to make contact with ES fixed contact (during pre-arcing time). The current transfer flange [20] is insulated from a grounded metallic enclosure [16] by using delrin insulating spacers [21]. This insulated current transfer flange [20] is connected to the grounding grid through grounding connectors separately.
[083] The ES moving arcing contact [17] is isolated from the operating link
[22], through an insulator cum guide [23] and metallic operating element [24]. The ES LT shield [25] is also provided on the spherical grounded enclosure to limit higher electrostatic fields around the ES current collector [19]. The ES drive system [22, 24,26,27] consists of an operating link [22], Lever arrangement [26] and shaft [27] provides the energy required fo r the operation of moving arcing contact [17] connected to insulator cum guide [23] and metallic operating element [24].
[084] FIG.6(b) illustrates the top view showing the connection between the
spherical connector and the Disconnector switch with insulator port [35] in a spherical grounded enclosure.

[085] The disconnector and earthing switch contact system have been arranged
in a spherical grounded enclosure [16]. To simplify the design of these switches, it is proposed to integrate them in the same housing a nd being operated by different drives as required by high voltage switchgear. The spherical grounded enclosure [16] consists of multiple ports to provide an epoxy insulator [08A, 08B, 08C] to support the spherical connector [01]. These ports are arranged optimally to limit the dimensions of the spherical grounded enclosure [16].
[086] Along with the ports [16D,16E] to accommodate epoxy insulators, other
ports [16F,16G] are provided to integrate the drive system of the disconnector switch and earthing switch. Other than these ports there shall be suitable ports [33] fo r gas filling and sensor [33A], viewing port [33B], protection system against gas pressure rise (rupture disk) [33C], protection against moisture (molecular sieve) [33D], etc. The epoxy insulators [08A, 08B] are also again classified as two types. One is to support spherical connector [01] through high voltage terminal [08B] and the other one [08A] is to support fixed contact assembly of disconnector switch.
[087] Minimum two epoxy insulators [08A,08B] are provided to support
spherical connector [01] when independent disconnector a nd earthing switches are in open condition. The advantage of the system is that the spherical connector is supported by a minimum of two insulators at any point of time and maybe more when one of the switches is in closed condition.
[088] The integrated disconnector cum earthing switch is designed with both
disconnector switch and earthing switch in the same enclosure by keeping o ne additional epoxy insulator [08C] through the insulator port [35]. This results in an increment in the bay width of GIS.
[089] In the above-mentioned configuration, to support a spherical connector
[01], it is required to accommodate at least one more epoxy insulator [08C] in addition to incoming and outgoing epoxy insulator [08A, 08B]. Moreover, to accommodate epoxy insulator [08C], a port [35] is required to be located on the spherical grounded enclosure [16]. Because of this epoxy insulator [08C],

additional dish cover [36], HT terminal [32A], HT shield [32B] and terminal shield [37] are required.
[090] To overcome the issues related to the above-mentioned assembly a nd to
optimize the dimensions of the combined disconnector cum earthing switch, a new assembly for combining both the switch in the same housing is proposed. It also helps in achieving the lowest bay width and depth of gas-insulated switchgear.
[091] The present disclosure proposes the insulator [34] that is used to support
the spherical connector [01] in addition to incoming and outgoing epoxy insulator [08A,08B], that results in the removal of port [35] from the spherical grounded enclosure [16].By proposing a insulator [34], items like additional epoxy insulator [08C], insulator port [35], dish end/cover [36], HT terminal [32A], HT shield [32B] and terminal shield [37] are also completely eliminated.
[092] The present disclosure also solves a technical problem associated with the
use of multiple epoxy insulators, as it increases the overall cost of the system. The present disclosure clearly explains the assembly that overcomes the problem associated with the prior arts in the below-mentioned explanation by figures.
[093] FIG.7(a) illustrates the integration of the insulator with spherical
connector assembly in accordance with the embodiment of the present disclosure.
[094] The insulator [34] consists of a tubular structure [34B] made of Fiber
Reinforced Polymer (FRP) or Kevlar or equivalent material whose first end is fixed to a plate [38] which is attached to the spherical grounded enclosure [16C] and the second e nd is fixed to spherical connector [01]. The first e nd of the tubular structure[34B] is also attached to the terminal which is at high voltage potential a nd the second end of the tubular structure [34B] is attached to the terminal at ground potential. The high voltage terminal [34A] of the FRP tubular structure [34B] are fixed through gluing [34D] shown in fig.7(b) and similarly the grounded terminal [34C] and FRP tubular structure [34B] is also fixed through gluing [34D]. The grounded terminal [34C] is connected to the plate

[38] firmly which in turn is fixed to the spherical grounded enclosure [16C]. In grounded enclosure [16C] the discharge /radial distance “D” is relatively small as sufficient gluing length is provided in between HV / grounded terminal [34A,34C] a nd insulating tubular structure [34B] are required to meet tensile and compression requirements. Precisely gluing is required on either side of the insulator [34].
[095] To reduce the distance “D”, the grounded terminal [34B] is located inside
the support plate [38] in a strategic manner. Further, the high voltage terminal of the insulator [34A] is fixed to the spherical connector [01] of the disconnector cum earthing switch module. The spherical connector [01] has different ports to extend high voltage connections to other modules of GIS. The critical portion of the design of the insulator [34] is the requirement of minimum radial/discharge distance between its high voltage [34A] and grounded terminals [34C]. In the DS-ES module, this radial distance “D” is limited by the dimensions of the spherical grounded enclosure [16C].
[096] In order to achieve reliable support, the insulator [34] has been plugged
inside the spherical connector [01] so that the spherical connector [01] acts as a primary shield fo r the insulator [34]. By keeping inside spherical connector [01], the surface electrical stress on the insulator [34] is found to be reduced significantly even with the shortest radial distance “D” of the insulator [34]. This optimal insulator [34] can be designed for higher and higher voltage class applications also i.e. example of Ultra-high voltage (UHV) applications.
[097] FIG.7(b) shows the enlarged view of the integration of the insulator with
Spherical connector assembly in accordance with the embodiment of the present disclosure.
[098] The high voltage terminal of / FRP insulator [34A] is placed inside the
spherical connector [01] at a gas gap “G” so that influence of electric stress on tri-junction formed by FRP, gas, a nd high voltage terminal is nullified and the highest stress point is shifted to spherical connector [01] which is well below an acceptable level. By doing so, the tangential stress on the insulator [34] is reduced significantly and may not generate discharge during service. For high

voltage applications, the high voltage and grounded terminals [34A, 34C] require good profiles a nd occupy larger dimensions in the absence of a spherical connector [01].
[099] The gas gap “G1”, “G2” and “G” are critical in achieving electric stress-
free zone on / FRP insulator [34]. By optimizing these parameters, the lowest discharge distance (D) from high voltage to the ground terminal can be achieved. The grounded terminal of the FRP tubular structure [34C] is fixed firmly on the plate [38] which is fixed to a spherical grounded enclosure [16C].
[0100] The present disclosure is mainly related to a gas-insulated disconnector
cum earthing switch, where a spherical connector [01] is used fo r extending electrical connections in multiple directions for connection of disconnector as well as earthing switch. In this assembly, the disconnector switch and earthing switch operates in perpendicular axis to each other or it can be oriented in any other direction. The spherical grounded enclosure [16C] is developed for the accommodation of the above dis-connector and earthing switch combined contact system efficiently.
[0101] FIG.8(a) shows Disconnector Switch with Insulator. In this, the spherical
grounded enclosure [16C] consists of multiple ports [16D,16E] to provide an insulator and epoxy insulator to support the spherical connector [01]. These ports are arranged optimally to limit the dimensions of the spherical grounded enclosure [16]. Two ports are located to accommodate epoxy and insulators, a port is provided to integrate the drive system of the disconnector switch. Minimum two insulators [08A,34] are provided to support a spherical connector [01] when both disconnector and earthing switches are in open condition.
[0102] FIG.8(b) shows Earthing Switch with FRP Insulator. In this, the
spherical grounded enclosure [16C] consists of multiple ports [16D,16E] to provide insulator and epoxy insulator to support the spherical connector [01]. These ports are arranged optimally to limit the dimensions of the spherical grounded enclosure [16]. Two ports are located to accommodate epoxy and insulators, a port is provided to integrate the drive system of earthing switch.

Minimum two insulators [08A, 34] are provided to support a spherical connector [01] when both disconnector and earthing switches are in open condition.
[0103] FIG.9 illustrates the 3D view of the grounded metallic enclosure for the
Disconnector cum earthing Switch system with an insulator.
[0104] The spherical grounded enclosure [16C] shall provide two openings
[16D,16E] fo r the extension of high voltage connection with other modules through epoxy insulator [08A,08B] and two openings [16F,16G] for connection of the drive mechanisms of DS and ES. The axis for drive housing opening is 90˚ to each other. The combined switch contact system is insulated from the spherical grounded enclosure [16C] with designed SF6 gas density.
[0105] The materials are given as an example without restricting the scope of the
invention to the same. Thus, other materials readily apparent to a person skilled in the art are understood to be within the purview of the invention.
[0106] The spherical grounded enclosure [16C] is profiled in such a way that the
electrostatic field around the contact system is highly uniform and result in a secondary breakdown free dis-connector and earthing switch. Axial E-field must be uniform between the contact shields during the operation of DS and ES.
[0107] The advantage associated with the proposed system is that the spherical
connector [01] is supported by a minimum of two insulators at any point of time and maybe more when one of the switches is in closed condition. The integrated disconnector cum earthing switch is structured with both disconnector switch and earthing switch in the same enclosure by keeping one additional insulator [34]. By using this insulator, the bay width of GIS is optimized substantially for disconnector-cum-earthing switch.
[0108] Thus, with the assembly described herein in the present disclosure,
various technical problems of the state of the art are resolved. Also, although a number of exemplary method options are described herein, those skilled in the art can appreciate that the assembly provides a single-phase disconnector switch (DS) along with earthing switch (ES) in a single enclosure, which helps in optimizing bay width in gas-insulated switchgear (GIS) bay and take necessary

action according, without deviating from the scope of the subject matter of the present disclosure.
[0109] The major function of the present disclosure is to provide an assembly
that accommodates a single-phase disconnector switch (DS) along with earthing switch (ES) in a single enclosure, which in turn helps in optimizing bay width in gas-insulated switchgear (GIS) bay.
TECHNICAL ADVANTAGES
[0110] The proposed assembly that is used fo r incorporating a disconnector
switch and an earthing switch in a single enclosure of Gas-insulated switchgear use FRP insulators support for conductor/contact assembly instead of bulky cone or disc epoxy insulators. Precisely, the proposed assembly helps in reducing cost, size of the module, and GIS bay width.
[0111] Moreover, the proposed FRP insulator provides lowest possible
discharge/radial distance between terminals and does no t require additional high voltage or grounded metallic shields. The FRP insulator is designed such that the mechanical strength of the insulator is ensured by using appropriate gluing or casted techniques. The FRP insulator has HT and grounded terminal with tubular structure of the insulator and designed with lowest possible radial/discharge distance.
TEST RESULTS
[0112] Bay Width of GIS bay reduced by 20%
[0113] DS cum ES module dimensions reduced by 30%
[0114] Cost of module reduced by 25%

WORKING OF INVENTION
[0115] An assembly for accommodating disconnector cum earthing switch is
developed and evaluated successfully against all test duties as per IEC. Some design features are already demonstrated at site and performance is found to be satisfactory.
[0116] Further, it will be appreciated that those skilled in the art will be able to
devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its scope.
[0117] Furthermore, all examples recited herein are principally intended
expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples a nd conditions. Also, the various embodiments described herein are no t necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.
[0118] While the foregoing describes various embodiments of the invention,
other and further embodiments of the invention ma y be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

We Claim:
1. An assembly (100) for incorporating a disconnector switch and an earthing switch in a single enclosure of Gas-insulated switchgear comprising a spherical grounded enclosure (16C) with a spherical connector (01) having multiple ports fo r incorporating an insulator (34) of tubular (34B) structure, wherein the first end of the tubular (34B) structure is connected to the spherical grounded enclosure (16C) and the second end is connected to the spherical connector (01).
2. The assembly (100) as claimed in claim 1, wherein the multiple ports of the spherical grounded enclosure (16C) comprising two insulator ports (16D,16E) fo r fixing of epoxy insulators and two drive ports (16F,16G) for fixing drive systems for DS and ES.
3. The assembly (100) as claimed in claim 2, wherein the two insulator ports (16D,16E) a nd two drive ports (08A,08B) provided on the spherical grounded enclosure (16C) are placed at 180 degrees to one another.
4. The assembly (100) as claimed in claim 2, wherein the two drive ports (16F,16G) for drive systems and the insulator ports (16D,16E) for epoxy insulators (08A,08B) are at 90 or 270 degrees to one another.
5. The assembly (100) as claimed in claim 2, wherein the spherical grounded enclosure (16C) comprises a multitude of ports fo r installing sensor (33A) for determining gas pressure, viewing port (33B), rupture disk (33C) for protecting the system against gas pressure rise, and molecular sieve (33D) protecting system against moisture.
6. The assembly (100) as claimed in claim 2, wherein the spherical connector (01) placed inside the spherical grounded enclosure (16C) with six ports fo r housing the current collector (02), DS moving arcing contact (04), self-contained shields (01A), insulating operating rod (05) , shield cum stopper (06) fo r the operation of Disconnector switch and fixed arcing contact (17) of Earthing switch.
7. The assembly (100) as claimed in claim 1, wherein the tubular structure (34B) of the insulator (34) is made of a material including FRP or Kevlar.

8. The assembly (100) as claimed in claim 1, wherein the first end of the tubular structure (34B) of the insulator (34) is connected to a ground terminal (34C) and the spherical grounded enclosure (16C).
9. The assembly (100) as claimed in claim 1, wherein the second end of the tubular structure (34B) of the insulator (34) is connected to a high voltage terminal (34A) and the spherical connector (01).
10. The assembly (100) as claimed in claim 1, wherein the high voltage terminal (34A) and tubular structure (34B) of insulator (34) is fixed through gluing and the grounded terminal (34C) and tubular structure (34B) is also fixed through gluing.
11. The assembly (100) as claimed in claim 1, wherein the HT and grounded terminal (34A,34C) of the tubular structure (34b) of the insulator (34) are fixed, that lowest possible radial /discharge distance, “D” can be achieved and sufficient gluing length of these terminals (34A,34C) can be ensured.