FIELD OF THE INVENTION
The present invention relates in general to a gas insulated Dis-connector switch
(DS) and Earthing Switch (ES) which are important modules of high voltage gas
insulated switchgear. More particularly, the present invention relates to a single
phase compact dis-connector switch and earthing switch both located in a single
enclosure, where DS is for making/interrupting capacitive currents and ES for
directly discharge of trapped charges in high voltage sections of gas insulated
switchgear equipment.
BACKGROUND OF THE INVENTION
Disconnector and earthing switch modules are important modules of gas
insulated metal-clad switchgear equipment. Disconnector switch (DS) is
provided to isolate/disconnect the parts of Gas insulated high voltage sections.
DS is employed to interrupt / make capacitive currents in system. An
insulating element is connected between movable contact and drive system to
have isolation for the drive system from high voltage. In the event of DS being
closed the capacitive charging current flows through the contacts of the DS in
proportion to the voltage and the section length.
Gas insulated earthing switch (ES) is normally provided in a 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 maintenance and shut down period, the live parts/section of a
substation are grounded through the earthing switches to ensure safety of the
maintenance personnel. The ES within GIS are also used as the return path
during calibration/accuracy assessment of a current transformer. Two types of
ES are recommended for GIS to cover all the requirements. First type is a low
speed maintenance earthing switch and second type is a high speed fault-proof
earthing switch. The fault-proof ES, connected at the entrance of a substation,
experiences fault current at system voltage “make” operation. 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 high voltage section of Gas insulated switch to ground. The moving contact is
connected to 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
ground.
In conventional switchgear, these modules are generally provided as
independent modules or both the modules or operated by same drive.
For Example, a combined Disconnector and earthing switch for a metal-
encapsulated, gas-insulated high-voltage switchgear assembly is disclosed in
US8487203B2. In this, a 3-position switch is structured such that when a
disconnecting switch-side moving contacts slide in a hollow disconnecting
switch-side conductor and earthing switch-side moving contacts slide in a
hollow earthing switch-side conductor, simultaneously (refer Figure 1(a) to 1 (c)).
Furthermore, US8624146B2 explains metal-encapsulated, gas-insulated,
combined three-phase disconnector and earthing switch. At first Position, it
connects to fixed contact of isolator. In a second position, it is connected to a
fixed Earthing contact piece and a drive motor. Drive motor actuates the
Contacts via a drive spindle. Contacts are driven by in each case one insulating
spindle (refer Figure 2(a), 2(b)). Further, US3665135 also, discloses similar
arrangement.
In most of above patents and other conventional techniques, common
mechanisms are used for the operation of the dis-connecting switch and
earthing switch. This philosophy is useful for the low voltage applications. In
this system, common mechanism results in same speed travel characteristics for
both the switches. But, for higher voltage applications, separate mechanisms
are used for DS and ES for reliable and to achieve different speed time
characteristics. This will further improve system response time too.

There is therefore a need to develop a compact design of Gas insulated dis-
connector switch and maintenance earthing switch design in common
enclosure/housing. There is a need to develop a design which is secondary
breakdown-free and acts as a reliable gas insulated disconnector switch by
ensuring transferring current with very low power losses and reliable contact
resistance system for earthing switch.
OBJECTS OF THE INVENTION
An object of the invention is to overcome the aforementioned and other
drawbacks existing in prior systems.
It is therefore a primary object of the present invention to provide a single
common housing for gas insulated dis-connector switch (DS) and earthing
switch (ES).
Further object of the present invention is to provide spherical connector to
accommodate fixed arcing contact assembly and moving contact assembly of
dis-connector as well as fixed contact assembly of earthing switch.
Still further object of the present invention is to provide spherical connector with
self contained shields.
Yet another object of the present invention is to provide an orientation of
disconnector switch and earthing switch in perpendicular axis or any degreed
orientation to each other.
Further object of the present invention is to provide a gas insulated dis-
connector switch and earth switch oriented in such a way that a reliable and
optimal design is achieved.
Still further object of the present invention is to provide simplification in
operation of the switches for ease in assembly.

Yet another object of the present invention is to provide a novel profile of fixed
contact shield of Earthing switch (ES).
Another object of the present invention is to provide an optimal positioning of
fixed contact shield with respect to fixed arcing contact of earthing switch.
Further object of the present invention is to provide a novel profile of fixed
contact shield of disconnector switch.
Yet another object of the present invention is to provide an optimal positioning
of fixed contact shield with respect to fixed arcing contact of disconnector
switch.
Still further object of the present invention is to provide separate drives and
drive housings for the operation of DS and ES.
Further object of the present invention is to provide a novel metallic enclosure
for accommodation of Disconnector and earthing switch.
SUMMARY OF THE INVENTION
The present application discloses a Gas Insulated Integrated Switch. In an
aspect, the integrated switch assembly includes a disconnector switch (DS) and
an earthing switch (ES) disposed at perpendicular to each other DS at one axis
and ES on the other axis. Further, the assembly includes a spherical connector
configured to house (i) a current collector, a moving contact shield and a moving
arcing contact of the DS and a fixed arcing contact of the ES, (ii) maintain
uniform temperature distribution of the gas insulated integrated switch, (iii) act
as a guide to a DS insulating operating rod for operating DS moving arcing
contact, (iv) and act as a DS current transfer connector for transferring current
from DS movable arcing contact through a DS current controller. Further, the
assembly includes a stopper cum shield designed to avoid over run of DS during
opening operation by ensuring uniform electric field across insulating operating
rod.

Further, in an aspect, the assembly has a contact system for DS which includes
a DS fixed contact of the DS held on a support insulator with an adapter and an
adapter shield, said DS fixed contact covered by a fixed contact shield, a DS
moving arcing contact surrounded by a DS moving contact shield when DS is in
open condition and in closed condition the DS moving arcing contact is plugged
into DS fixed contact, said DS moving arcing contact is housed in the spherical
connector, a DS current collector for effecting dynamic current transfer of
discharge/arcing current from the DS fixed contact to the spherical connector
through the DS movable arcing contact during pre-arcing time, a DS drive
system for effecting DS operation by providing energy to the DS moving arcing
contact and an insulating operating rod to which the DS drive system is
attached.
Furthermore, in an aspect, the assembly has a contact system for ES which
includes an ES fixed contact of the ES is fixed on the spherical connector, an ES
moving arcing contact plugged into ES fixed contact when the ES is in closed
combination while in the open condition the ES fixed contact is surrounded by
fixed contact shield, an ES current collector for effecting dynamic current
transfer of discharge/arcing current from the ES fixed contact to a current
transfer flange through the ES movable arcing contact during pre-arcing time.
Further, in an aspect, the assembly includes an ES drive system for providing
energy resumed for operation of the moving arcing contact which is connected to
an insulator cum guide and metallic operating element. Furthermore, the
assembly includes a profile of DS guide tube, a profile of ES guide tube and a
profile of insulator cum guide configured such that to avoid pressure build up in
DS drive housing and ES derive housing respectively. Further, the assembly
includes a an integrated switch housing for housing the DS and the ES contact
system, said integrated switch housing having multiple parts constructed
optimally to limit dimensions of the integrated switch housing, said integrated
switch housing accommodating at least two support insulators, said integrated
switch housing is disposed such that axial electrostatic field around the contact
systems is uniform, thereby resulting in secondary breakdown free DS and ES.

The above and additional advantages of the present invention will become
apparent to those skilled in the art from a reading of the following detailed
description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The above brief description, as well as further objects, features and advantages,
of the present invention can be fully appreciated by reference to the following
detailed description. These features of the present invention will become more
apparent upon reference to the drawings, wherein:
Figure 1: Conventional Metal-encapsulated, gas-insulated, combined
disconnector and earthing switch.
Figure 2: Conventional Metal-encapsulated, gas-insulated, combined
disconnector and earthing switch.
Figure 3: Illustrates spherical connector with DS and ES contacts assembly.
Figure 4: Illustrates contact system of Dis-connector switch arrangement.
Figure 5: Illustrates contact system of Earthing switch arrangement.
Figure 6: Illustrates of Novel FC shield and fixed arcing contact of disconnector
switch.
Figure 7: Illustrates disposition of Novel FC shield and fixed arcing contact of
earthing switch.
Figure 8: Illustrates disposition of grounded metallic enclosure for combined
switch system.
Figure 9: Illustrates integrated switch for gas insulated substation of combined
disconnector and earthing switch system.
DETAILED DESCRIPTION OF THE INVENTION
Although the disclosure hereof is detailed and exact to enable those skilled in
the art to practice the invention, the physical embodiments herein disclosed
merely exemplify the invention which may be embodied in other specific
structure. While the preferred embodiment has been described, the details may

be changed without departing from the invention, which is defined by the
claims.
It will be apparent, however, to one of ordinary skill in the art that the present
invention may be practiced without specific details of the well known
components and techniques. Further specific numeric references should not be
interpreted as a literal sequential order. Thus, the specific details set forth are
merely exemplary. The specific details may be varied from and still be
contemplated to be within the scope of the present invention. The features
discussed in an embodiment may be implemented in another embodiment.
Moreover, occasional references to the conventional systems are made in order
to better distinguish the present inventive disclosure discussed later in greater
detail. Few of the details pertaining to said assemblies are well known in the art
and therefore, are described herein only in the detail required to fully disclose
the present invention while unnecessarily obscuring the present invention. The
present invention will be described in detail below with reference to
embodiments as shown in the drawings.
In an embodiment, a spherical shaped universal connector 01 has been
designed and suggested to meet all connection requirement of metal clad gas
insulated substation equipment. Spherical connector 01 is a unique component
designed to cater multiple requirements in compact switchgear equipment to
accommodate disconnector Switch (DS) and earthing Switch (ES) connections.
The objective of the connector is to transfer current from one module of the
switchgear / power equipment to another module. It is also to commensurate
electric stress relieved connection in different orientations like “L”, “T” or 00-900
of any orientation. The spherical connector provides low resistance path with
controlled electrical stress around its geometry i.e., self contained shields (refer
Figure 3).
In an embodiment, the spherical connector 01 acts as housing for current
collector 02, moving contact shield 03 and moving arcing contact 04 of

disconnector switch, also it acts as housing for fixed arcing contact 17 of
Earthing Switch. The invented spherical connector 01 can also act as a guide to
DS insulating operating rod 05 used for operation of DS moving arcing contact
04. The invented spherical connector 01, is to act 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.
The DS current collector 02 also acts as stopper for disconnector switch during
its closing operation. A stopper cum shield 06 is integrated to the spherical
connector which has a provision of stopper arrangement to avoid over run of
disconnector switch during opening operation. This profile of stopper cum shield
06 ensures uniform electric field across insulating operating rod 05. The
spherical connector 01 is self-contained and is an electrically stress relieved
component, which is also facilitated with high level cooling by means of suitable
gas flow vents. This arrangement helps in maintaining uniform temperature
distribution for the switchgear equipment.
In one axis, the fixed contact 07 of the disconnector switch (DS) held on a
support insulator 08 with suitable adapter 09 and Adapter shield 10. 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. The DS moving arcing contact 04 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 as Spherical connector 01. The DS
drive system 12 provides the energy required for the operation of DS movable
contact system. The DS operation is achieved by using moving arcing contact 04
and insulating operating rod 05 which on another side attached to DS drive
system 12 which consist of an operating link 13, Lever arrangement 14 and
shaft 15. The entire contact system is insulated from the grounded metallic
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. Figure 4a shows the contact system
of disconnector switch while in opened position. When the disconnector switch

is in close condition, the DS moving contact 04 is plugged into DS fixed contact
07. A 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). Fixed contact 09 and moving arcing contact 04 are integrated to shield to
protect the high voltage system from secondary breakdown. Figure 4 shows
contact arrangement of disconnector switch during open and close conditions.
In other axis (45 to 135 degrees), preferably 900, ES fixed contact 17 is fixed on
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. 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 19 when the ES movable arcing contact 18 is about to make
contact with ES fixed contact (during pre-arcing time). The current transfer
flange 19 is insulated from grounded metallic enclosure 16 by using special
insulating spacers 21. This insulated current transfer flange 19 is connected to
grounding grid through grounding connectors separately. The advantage with
this type of connection is calibration of current transformers can be performed
during service without opening GIS. One more advantage with this model is that
high fault current need not pass through grounded enclosures. 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 drive system 25
consists of an operating link 22, Lever arrangement 26 and shaft 27 provides
the energy required for the operation of moving arcing contact 17 connected to
insulator cum guide 23 and metallic operating element 24. Figure 5 shows
contact arrangement of earthing switch.

Further, the FC shield 17A of ES has two functions. One is to provide the
uniform electric field between the contact system and other important function
is to be capable to work against pre arcing during making duty of earthing
switches. Precisely, earthing switch is required to discharge small to large
voltages left on the high voltage switchgear equipment. In this process, there is a
possibility of making of current of few amperes to thousands of amperes by
earthing switches. When earthing switch is in the making duty at certain
percentage of system voltage, there is a possibility of pre arcing between the
contact system depending on left over voltage and speed of the drive. Most of the
times, initial pre-arcing takes place between moving arcing contact and fixed
contact shield (rather than fixed arcing contact 17). Hence, fixed contact shield
17A shall not be made with high conductivity material alone. It is preferable to
use a FC shield 17A of high resistive tungsten type material instead of high
conductivity material. Economically, it is not possible to use purely high
resistive and low erosive material as well as mix of high resistive/low erosive and
conductive material of these dimensions. Hence a new design with high resistive
material with low erosive tip 17B of predefined profile to perform against arcing
is introduced. The advantage with such system is to limit pre-arcing through FC
shield 17A and involve fixed arcing contact at the earliest instant during pre-
arcing period. It is also important that FC shield 17A shall not be involved in
arcing process for a long time as it disturbs the electric field distribution in case
of its damage against arcing. The novelty of proposed design is that the FC
shield 17A is located with respect to fixed contact in such a way that the electric
field distribution across contact system shall be uniform. The concept is further
extended to disconnector switch, where current involved is less compared to fast
acting earthing switch. Even then, pre-arcing time is in the range of few ms
(milliseconds). To improve reliability of the FC shield 11 of disconnector switch,
the FC shield is arranged with uniform annular gap from the fixed arcing
contact 17 arrangement.
Further, the DS Guide tubes 28 and ES guide tubes 29 are designed in such a
way that it has suitable opening area to avoid unwanted pressure build-up in

DS drive housing 30 and ES drive housing 31 during opening/closing operation
which otherwise affect operating speed characteristics. The dis-connector and
earthing switch contact system has been arranged in spherical grounded
enclosure 16. To simplify the design of theses switches, it is proposed to
integrate them in same housing and being operated by different drives as
required by high voltage switchgear. Hence, this type of combined module is
called Integrated Switch. The integrated switch housing 16 consists of multiple
ports to provide support insulator 32 made of epoxy to support the spherical
connector 01. These ports are arranged optimally to limit the dimensions of
integrated switch housing 16. Along with the ports to accommodate support
insulators, other ports are provided to integrate drive system of disconnector
switch and earthing switch. Other than these ports there shall be suitable ports
for gas filling, gas sensors, protection system against gas pressure rise,
protection against moisture etc 33. The support insulators 32 are also again
classified as two types. One is to support spherical connector 01 through high
voltage terminal and other one is to support fixed contact assembly of
disconnector switch. Minimum two support insulators 32 are provided to
support spherical connector 01 when both disconnector and earthing switches
are in open condition. Advantage of the system is that, the spherical connector
is supported by minimum of two insulators at any point of time and may be
more when one of the switch is in closed condition. Figure 8 shows the invented
grounded metallic enclosure for integrated switch system. Three phase system is
also developed using the above arrangement.
The novel compact gas insulated disconnector switch with earthing switch has a
spherical connector 01 is used for extending electrical connections in multiple
directions for connection of disconnector as well as earthing switch. In the
designed combined switch, disconnector switch (DS) and earthing switch (ES)
operates in perpendicular axis to each other. Special type spherical grounded
enclosure 16 is developed for accommodation of the above dis-connector and
earthing switch combined contact system. The spherical grounded enclosure 16
is profiled in such a way that the electrostatic field around the contact system is
highly uniform and result into a secondary breakdown free dis-connector and

earthing switch. Axial E-field must be uniform between the contact shields
during operation of DS and ES. The invented grounded metallic enclosure 16
will provide three openings for the extension of high voltage connection with
other modules through support insulator 10 and two openings for connection of
the drive mechanisms of DS and ES. The axis for drive housing opening are 90˚
to each other. The combined switch contact system is insulated from the
grounded metallic enclosure 16 with designed SF6 gas density. Figure 9 shows
the integrated disconnector and earthing switch for gas insulated substation.
The foregoing is considered as illustrative only of the principles of the invention.
Furthermore, since numerous modifications and changes will readily occur to
those skilled in the art, it is not desired to limit the invention to the exact
construction and operation shown and described. While the preferred
embodiment has been described, the details may be changed without departing
from the invention, which is defined by the claims.

We claim:
1. A novel gas insulated integrated switch comprising:
a disconnector switch (DS) and an earthing switch (ES) disposed at
perpendicular, or any other required angle to each other with DS at one axis
and ES on the other axis.
a spherical connector (01) configured to house (i) a current collector
(02), a moving contact shield (03) and a moving arcing contact (07) of the DS
and a fixed arcing contact (17) of the ES, (ii) maintain uniform temperature
distribution of the gas insulated integrated switch, (iii) act as a guide to a DS
insulating operating rod (05) for operating DS moving arcing contact (04), (iv)
and act as a DS current transfer connector for transferring current from DS
movable arcing contact (04) through a DS current controller (02);
a stopper cum shield (06) designed to avoid over run of DS during
opening operation by ensuring uniform electric field across insulating
operating rod (05);
a contact system for DS comprising:
a DS fixed contact (07) of the DS held on a support insulator
(08) with an adapter (09) and an adapter shield (10), said DS
fixed contact (07) covered by a fixed contact shield (11),
a DS moving arcing contact (04) surrounded by a DS moving
contact shield (03) when DS is in open condition and in closed
condition the DS moving arcing contact (04) is plugged into
DS fixed contact (07), said DS moving arcing contact is
housed in the spherical connector (01),
a DS current collector (02) for effecting dynamic current
transfer of discharge/arcing current from the DS fixed contact
(07) to the spherical connector (01) through the DS movable
arcing contact (04) during pre-arcing time,

a DS drive system (12) for effecting DS operation by providing
energy to the DS moving arcing contact (04) and an insulating
operating rod (05) to which the DS drive system (12) is
attached;
a contact system for ES comprising:
an ES fixed contact of the ES is fixed on the spherical
connector (01),
an ES moving arcing contact (18) plugged into ES fixed
contact (17) when the ES is in closed condition while in the
open condition the ES fixed contact (17) is surrounded by
fixed contact shield (17A),
an ES current collector (19) for effecting dynamic current
transfer of discharge/arcing current from the ES fixed contact
(17) to a current transfer flange (19) through the ES movable
arcing contact (18) during pre-arcing time;
an ES drive system (25) for providing energy resumed for
operation of the moving arcing contact (17) which is connected to an
insulator cum guide (23) and metallic operating element (24);
a profile of DS guide tube (28), a profile of ES guide tube (29) and a
profile of insulator cum guide (23) configured such that to avoid
pressure build up in DS drive housing (30) and ES derive housing
(31) respectively;
an integrated switch housing (16) for housing the DS and the
ES contact system, said integrated switch housing (16) having
multiple ports constructed optimally to limit dimensions of the
integrated switch housing (16), said integrated switch housing (16)
accommodating at least two support insulators (32), said integrated
switch housing (16) is disposed such that axial electrostatic field

around the contact systems is uniform, thereby resulting in
secondary breakdown free DS and ES.
2. The integrated switch as claimed in claim 1, wherein the drive system (12,
25) comprises an operating link (13, 22), a lever arrangement (14, 26) and a
shaft (15, 27).
3. The integrated switch as claimed in claim 1, wherein the DS and the ES
contact unit is insulated from the integrated switch housing (16) with SF6
gas density.
4. The integrated switch as claimed in claim 1, wherein the DS moving
contact shield (03) is separated from the DS fixed contact shield (11) by a
distance ‘D’ proportional to applied voltage and the SF6 gas density.
5. The integrated switch as claimed in claim 1, wherein orientation of
positioning of the ES moving arcing contact (18) and the DS moving arcing
contact (02) is between 450 to 1350.
6. The integrated switch as claimed in claim 1, wherein the current transfer
flange (19) is insulated from integrated switch housing (16) through special
insulating spacers (21).
7. The integrated switch as claimed in claim 1, wherein the fixed contact
shield (17A) is designed with low erosive tip (17B) which is made of high
resistive tungsten type material for providing shielding against arcing.
8. The integrated switch as claimed in claim 1, wherein the fixed contact
shield (17A) is disposed with respect to the ES fixed contact (17) such that
the electric field distribution across the ES contact system is uniform.

9. The integrated switch as claimed in claim 1, wherein the fixed contact
shield (11) of DS is positioned such that there is uniform annular gap from
the fixed arcing contact (17).
10. The integrated switch as claimed in claim 1, wherein the contact systems
are insulated from the integrated switch housing (16) with SF6 gas density.
11. The integrated switch as claimed in claim 1, wherein the DS drive
housing (30) and the ES drive housing (31) are aligned at an angle to each
other.
12. The integrated switch as claimed in claim 1, wherein the integrated
switch housing (16) has three openings for extension of high voltage
connections with other modules through support insulator (32) and two
openings for connection of drive system of DS and ES.