U.S. patent application number 09/918807 was filed with the patent office on 2002-01-24 for gas insulation switch.
This patent application is currently assigned to Hitachi, Ltd.. Invention is credited to Honma, Hiroki, Sasaki, Koji, Yamagiwa, Tokio.
Application Number | 20020008958 09/918807 |
Document ID | / |
Family ID | 13620911 |
Filed Date | 2002-01-24 |
United States Patent
Application |
20020008958 |
Kind Code |
A1 |
Yamagiwa, Tokio ; et
al. |
January 24, 2002 |
Gas insulation switch
Abstract
To provide a gas insulation switch reducing the SF.sub.6 gas use
amount without damaging the insulation performance and arc
extinguishing performance, the present invention uses SF.sub.6 gas
as insulating gas to be charged in the grounding tank 1 of a unit
having a switching unit of the breaker 5, the disconnecting
switches 3, 4, and 8, and the grounding switches 6, 7, and 9, for
example, the line unit 190 and uses gas having a smaller warming
coefficient than that of SF.sub.6 gas, for example, nitrogen gas
23, or air as insulating gas to be charged in the grounding tank 1
of a unit having no switching unit, for example, the main bus units
100 and 110 and the connection bus unit 160.
Inventors: |
Yamagiwa, Tokio;
(Hitachi-shi, JP) ; Honma, Hiroki; (Hitachi-shi,
JP) ; Sasaki, Koji; (Mito-shi, JP) |
Correspondence
Address: |
MATTINGLY, STANGER & MALUR
Suite 370
1800 Diagnal Road
Alexandria
VA
22314
US
|
Assignee: |
Hitachi, Ltd.
|
Family ID: |
13620911 |
Appl. No.: |
09/918807 |
Filed: |
August 1, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09918807 |
Aug 1, 2001 |
|
|
|
09273502 |
Mar 22, 1999 |
|
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|
6292356 |
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Current U.S.
Class: |
361/612 |
Current CPC
Class: |
H02B 1/22 20130101; H01H
2033/566 20130101; H02B 5/06 20130101 |
Class at
Publication: |
361/612 |
International
Class: |
H02B 001/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 25, 1998 |
JP |
10-76979 |
Claims
What is claimed is:
1. A gas insulation switch comprising a container charged with
insulating gas which contains an electric conductor and a pair of
contacts which can be connected or disconnected and which is
divided into a plurality of gas sections, wherein as insulating gas
of a gas section containing no contact among said plurality of gas
sections, insulating gas having a smaller earth warming coefficient
than that of SF.sub.6 (sulphur hexafluoride) gas is used.
2. A gas insulation switch comprising a unit housing a breaker in a
first grounding tank and a unit housing an electric conductor
supported by an insulating support member in a second grounding
tank, wherein said first grounding tank is charged with SF.sub.6
(sulphur hexafluoride) gas and said second grounding tank is
charged with insulating gas having a smaller earth warming
coefficient than that of said SF.sub.6 (sulphur hexafluoride)
gas.
3. A gas insulation switch comprising a unit housing a breaker in a
first grounding tank, a unit housing a conductor supported by an
insulating support member in a second grounding tank, and a unit
containing a grounding switch in a third grounding tank, wherein
said first grounding tank is charged with SF.sub.6 (sulphur
hexafluoride) gas and said second and third grounding tanks are
charged with gas having a smaller earth warming coefficient than
that of SF.sub.6 (sulphur hexafluoride) gas.
4. A gas insulation switch according to one of claims 1 to 3,
wherein insulating gas having a smaller earth warming coefficient
than that of said SF.sub.6 (sulphur hexafluoride) gas is one of
nitrogen gas, and air.
5. A gas insulation switch according to claim 3, wherein said
second grounding tank is charged with nitrogen gas or air and said
third grounding tank is charged with mixed gas.
6. A gas insulation switch according to claim 2 or 3, wherein the
pressure in said grounding tank charged with insulating gas having
a smaller earth warming coefficient than that of said SF.sub.6
(sulphur hexafluoride) gas is set higher than the pressure in said
grounding tank charged with said SF.sub.6 (sulphur hexafluoride)
gas.
7. A gas insulation switch according to claim 2 or 3, wherein said
grounding tanks are mechanically connected via insulating spacers
having conical convexes and arranged so that said convexes are
located on the side of said grounding tanks charged with insulating
gas having a smaller earth warming coefficient than that of said
SF.sub.6 (sulphur hexafluoride) gas.
8. A gas insulation switch according to claim 2 or 3, wherein said
grounding tanks charged with insulating gas having a smaller earth
warming coefficient than that of said SF.sub.6 (sulphur
hexafluoride) gas are used as SF.sub.6 (sulphur hexafluoride) gas
collector containers.
9. A gas insulation switch comprising a first unit housing a
breaker in a grounding tank and a second unit housing an electric
conductor supported by an insulating support member in a grounding
tank, wherein said grounding tank of said first unit is charged
with SF.sub.6 (sulphur hexafluoride) gas, and said grounding tank
of said second unit is charged with insulating gas having a smaller
dielectric strength than that of said SF.sub.6 (sulphur
hexafluoride) gas at the same pressure, and furthermore the
insulation size of said second unit is made larger than the
insulation size of said first unit in correspondence with said
smaller dielectric strength.
10. A gas insulation switch comprising a first unit housing a
breaker in a grounding tank and a second unit housing an electric
conductor supported by an insulating support member in a grounding
tank, wherein said grounding tank of said first unit is charged
with SF.sub.6 (sulphur hexafluoride) gas, and said grounding tank
of said second unit is charged with insulating gas having a smaller
dielectric strength than that of said SF.sub.6 (sulphur
hexafluoride) gas at the same pressure, and furthermore the
pressure in said grounding tank of said second unit is made higher
than the pressure in said grounding tank of said first unit in
correspondence with said smaller dielectric strength, and the
thickness of said grounding tank of said second unit is made wider
in correspondence with said higher pressure in said grounding
tank.
11. A gas insulation switch according to claim 9 or 10, wherein
insulating gas having a smaller dielectric strength than that of
said SF.sub.6 (sulphur hexafluoride) gas at the same pressure is
gas having a smaller earth warming coefficient than that of said
SF.sub.6 (sulphur hexafluoride) gas and said insulating gas is
nitrogen gas, or air.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a gas insulation switch
suitable for earth anti-warming measures. For example, as described
in Engineering Report of Japanese Electrotechnical Committee, No.
552, "Application Guide of Gas Insulation Switch (GIS)" (issued on
July 1995), the gas insulation switch (hereinafter called GIS)
comprises a single or a plurality of gas insulated units and is
installed in a switching station or substation. Each gas insulated
unit comprises a grounding steel tank containing high voltage units
such as a conductor unit, conductor connection unit, and switching
unit and insulating spacers arranged so as to reserve an insulation
distance between the high voltage units and the grounding tank, or
so as to support the high voltage units, or so as to divide the
grounding tank for each gas. As insulating gas, sulphur gas
hexafluoride (hereinafter called SF.sub.6 gas) having superior
insulation performance and arc extinguishing performance has been
used since 1970.
SUMMARY OF THE INVENTION
[0002] The GIS containing all charged units in the grounding steel
tank is hardly affected by weather conditions, superior in
environment resistance, and advantageous in reduction of the site
of a switching station or substation, so that it has made rapid
progress. Recently, however, SF.sub.6 gas using for insulation of
the GIS has an earth warming coefficient of about 24000 times of
that of carbon dioxide (CO.sub.2) and it is indispensable to reduce
the use amount in the future from a viewpoint of anti-warming
measures. As one of the SF.sub.6 gas use amount reduction methods,
application of mixed gas may be considered. However, when the gas
is used for all the units constituting the GIS, the processing
method in case of emergency such as gas separation is complicated.
Therefore, it cannot be always said that it is a valid method.
[0003] The present invention is realized in consideration of the
aforementioned conditions and provides a gas insulation switch for
reducing the SF.sub.6 gas use amount. The present invention also
provides a gas insulation switch for reducing the SF.sub.6 gas use
amount without damaging the insulation performance and arc
extinguishing performance. The present invention also provides a
gas insulation switch for simply processing insulating gas and
reducing the SF.sub.6 gas use amount.
[0004] The first invention is a gas insulation switch comprising a
container charged with insulating gas which contains an electric
conductor and a pair of contacts which can be connected or
disconnected and which is divided into a plurality of gas sections,
wherein as insulating gas of a gas section containing no contact
among the plurality of gas sections, insulating gas having a
smaller earth warming coefficient than that of SF.sub.6 gas is
used.
[0005] The second invention is a gas insulation switch comprising a
unit housing a breaker in a first grounding tank and a unit housing
an electric conductor supported by an insulating support member in
a second grounding tank, wherein the first grounding tank is
charged with SF.sub.6 gas and the second grounding tank is charged
with insulating gas having a smaller earth warming coefficient than
that of the aforementioned SF.sub.6 gas.
[0006] The third invention is a gas insulation switch comprising a
unit housing a breaker in a first grounding tank, a unit housing a
conductor supported by an insulating support member in a second
grounding tank, and a unit containing a grounding switch in a third
grounding tank, wherein the first grounding tank is charged with
SF.sub.6 gas and the second and third grounding tanks are charged
with gas having a smaller earth warming coefficient than that of
SF.sub.6 gas.
[0007] The gas insulation switches of the first to third inventions
mentioned above use one of nitrogen gas, and air, as insulating gas
having a smaller earth warming coefficient than that of SF.sub.6
gas. In the gas insulation switch of the third invention, the
second grounding tank is charged with nitrogen gas or air and the
third grounding tank is charged with mixed gas.
[0008] In the gas insulation switch of the second or third
invention mentioned above, the pressure in the grounding tank
charged with insulating gas having a smaller earth warming
coefficient than that of SF.sub.6 gas is set higher than the
pressure in the grounding tank charged with SF.sub.6 gas. The
grounding tanks are mechanically connected via insulating spacers
having conical convexes and arranged so that the convexes are
located on the side of the grounding tanks charged with insulating
gas having a smaller earth warming coefficient than that of
SF.sub.6 gas. The grounding tanks charged with insulating gas
having a smaller earth warming coefficient than that of SF.sub.6
gas are used as SF.sub.6 gas collector containers.
[0009] The fourth invention is a gas insulation switch comprising a
first unit housing a breaker in a grounding tank and a second unit
housing an electric conductor supported by an insulating support
member in a grounding tank, wherein the grounding tank of the first
unit is charged with SF.sub.6 (sulphur hexafluoride) gas, and the
grounding tank of the second unit is charged with insulating gas
having a smaller dielectric strength than that of the
aforementioned SF.sub.6 (sulphur hexafluoride) gas at the same
pressure, and furthermore the insulation size of the second unit is
made larger than the insulation size of the first unit in
correspondence with the smaller dielectric strength.
[0010] The fifth invention is a gas insulation switch comprising a
first unit housing a breaker in a grounding tank and a second unit
housing an electric conductor supported by an insulating support
member in a grounding tank, wherein the grounding tank of the first
unit is charged with SF.sub.6 (sulphur hexafluoride) gas, and the
grounding tank of the second unit is charged with insulating gas
having a smaller dielectric strength than that of the
aforementioned SF.sub.6 (sulphur hexafluoride) gas at the same
pressure, and furthermore the pressure in the grounding tank of the
second unit is made higher than the pressure in the grounding tank
of the first unit in correspondence with the smaller dielectric
strength, and the thickness of the grounding tank of the second
unit is made wider in correspondence with the higher pressure in
the grounding tank.
[0011] The gas insulation switch of the fourth or fifth invention
mentioned above uses gas having a smaller earth warming coefficient
than that of SF.sub.6 (sulphur hexafluoride) gas as insulating gas
having a smaller dielectric strength than that of SF.sub.6 (sulphur
hexafluoride) gas at the same pressure and the gas having a smaller
earth warming coefficient is nitrogen gas, or air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a plan view showing the whole constitution of a
gas insulation switch of an embodiment of the present
invention.
[0013] FIG. 2 is a cross sectional view of the II-II field shown in
FIG. 1.
[0014] FIG. 3 is a cross sectional view schematically showing the
constitution of a part of FIG. 1.
[0015] FIG. 4 is a cross sectional view showing the constitution of
a main bus unit, line unit, and connection bus unit shown in FIG. 3
more in detail.
[0016] FIG. 5 is a cross sectional view showing the constitution of
the bus connection unit shown in FIG. 3 more in detail.
[0017] FIG. 6 is a cross sectional view showing the constitution of
the bus classification unit shown in FIG. 3 more in detail.
[0018] FIG. 7 is a cross sectional view showing the constitution of
an insulating spacer used in the gas insulation switch of this
embodiment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0019] The embodiment of the present invention will be explained
hereunder with reference to the accompanying drawings. FIG. 1 shows
an appearance constitution of a GIS of this embodiment and FIG. 2
shows a cross sectional view of the II-II field shown in FIG. 1. In
the drawings, numerals 100 and 110 indicate main bus units. Between
the main bus units 100 and 110 and a bushing 170 connected to the
transmission line, a line unit 190 comprising bus side
disconnecting switch unit devices 120 and 130, a disconnecting
switch unit device 140, and a line side disconnecting switch unit
device 150 and a connection bus unit 160 are installed for each
phase and the main bus units 100 and 110 and the bushing 170 are
electrically connected to each other. At the line lead-in opening,
a lightning arrester unit 180 having a lightning arrester for
controlling an overvoltage is installed. Numerals [1] to [5] shown
in FIG. 2 indicate classification of the unit devices constituting
the line unit 190 and the portion put between [1] and [2] indicates
the bus side disconnecting switch unit device 120. The portion put
between [1], [2], and [3] indicates the bus side disconnecting
switch unit device 130. The portion put between [3] and [4]
indicates the disconnecting switch unit device 140. The portion put
between [4] and [5] indicates the line side disconnecting switch
unit device 150.
[0020] FIG. 3 shows a part of the constitution shown in FIG. 1
which is enlarged and schematically shown. To the main bus units
100 and 110, line units 190a to 190d are connected via insulating
spacers 10. To the line units 190a to 190d, connection bus units
160a to 160d are connected via the insulating spacers 10. Between
the main bus unit 100 and the main bus unit 110, a bus connection
unit 200 is connected via the insulating spacers 10. Midway on the
main bus units 100 and 110, bus classification unit devices 210a
and 210b divided for each gas by the insulating spacers 10 are
installed.
[0021] FIG. 4 shows the constitution of the main bus units 100 and
110, the line unit 190, and the connection bus unit 160 shown in
FIG. 3 more in detail. The main bus units 100 and 110 house central
conductors 2 for three phases in a batch in a grounding tank 1. The
central conductors 2 branch halfway for each phase, supported by
the insulating spacers 10, and extended on the side of the line
unit 190. The line unit 190 constitutes the bus side disconnecting
switch unit devices 120 and 130, the breaker unit device 140, and
the line side disconnecting switch unit device 150 by dividing
inside a grounding tank 1 by insulating spacers 11.
[0022] The bus side disconnecting switch unit device 120 houses a
breaker 3 installed midway on the central conductor 2 toward the
breaker unit device 140 from the main bus unit 100 via the
insulating spacers 10 in the grounding tank 1. The bus side
disconnecting switch unit device 130 houses a breaker 4 installed
midway on the central conductor 2 toward the breaker unit device
140 from the main bus unit 100 via the insulating spacers 10 in the
grounding tank 1.
[0023] The breaker unit device 140 houses a breaker 5 installed
midway on the central conductor 2 toward the line side
disconnection switch unit device 150 from the point portion of the
central conductor 2 extended from the bus side disconnection switch
unit device 120 via the insulating spacers 11 and the central
conductor 2 extended from the bus side disconnection switch unit
device 130 via the insulating spacers 11 in the grounding tank 1.
At both ends of the breaker 5, grounding switches 6 and 7 with one
end of each of them connected to the grounding tank 1 are
installed.
[0024] The line side disconnecting switch unit device 150 houses a
breaker 8 installed midway on the central conductor 2 toward the
connection bus unit 160 from the breaker unit device 140 via the
insulating spacers 10 in the grounding tank 1. At one end of the
breaker 8, a grounding switch 9 with one end thereof connected
inside the grounding tank 1 is installed.
[0025] The connection bus unit 160 houses the central conductor 2
in the grounding tank 1 and the central conductor 2 extends to the
bushing 170 via an insulating spacer not shown in the drawing.
[0026] The line unit 190 divided by the insulating spacers 10 has a
switching unit of the breaker 5, the disconnecting switches 3, 4,
and 8, and the grounding switches 6, 7, and 9 and the current
breaking performance is required. Therefore, this embodiment uses
SF.sub.6 gas 22 superior in the insulation performance and arc
extinguishing performance as insulating gas to be charged in the
grounding tank 1 of the line unit 190. On the other hand, the main
bus units 100 and 110 and the connection bus unit 160 have no
switching unit such as a breaker in the grounding tank 1, so that
no current breaking performance is required. Therefore, this
embodiment uses nitrogen gas 23 or air which is gas having a
smaller warming coefficient than that of SF.sub.6 gas as insulating
gas to be charged in the grounding tank 1 of the main bus units 100
and 110 and the connection bus unit 160.
[0027] Furthermore, in this embodiment, the grounding tank 1
constituting the line unit 190 is divided into the bus side
disconnecting switch unit devices 120 and 130, the breaking unit
device 140, and the line side disconnecting switch unit device 150
by the insulating spacers 11, so that the line unit 190 can be
easily assembled and the charging gas pressure can be changed
depending on the current breaking performance.
[0028] Furthermore, in this embodiment, in the portions divided by
the insulating spacers 10 and the insulating spacers 11, that is,
in the bus side disconnecting switch unit devices 120 and 130 and
the line side disconnecting switch unit device 150, the
disconnecting switches 3, 4, and 8 are installed and for the
divided portions, a current breaking performance like that for the
breaker 5 is not required. Therefore, mixed gas which is gas having
a smaller warming coefficient than that of SF.sub.6 gas may be
used.
[0029] FIG. 5 shows the constitution of the bus connection unit 200
shown in FIG. 3 more in detail. The bus connection unit 200
connects between the main bus unit 100 and the main bus unit 110
and houses the central conductors 2 for three phases in a batch in
the grounding tank 1 divided by the insulating spacers 10. Midway
on the central conductor 2, a disconnecting switch 13, a breaker
12, and a disconnecting switch 14 are installed. At both ends of
the breaker 12, grounding switches 15 and 16 with one end of each
of them-connected to the grounding tank 1 are installed. In the bus
connection unit 200, the current breaking performance is required,
so that SF.sub.6 gas 22 is charged in the grounding tank 1 as
insulating gas.
[0030] FIG. 6 shows the constitution of the bus classification unit
210 shown in FIG. 3 more in detail. The bus classification unit 210
is divided by the insulating spacers 10 midway on the main bus
units 100 and 110 and houses the central conductors 2 for three
phases in a batch in the grounding tank 1 divided by the insulating
spacers 10. Midway on the central conductor 2, a disconnecting
switch 18, a breaker 17, and a disconnecting switch 19 are
installed. At both ends of the breaker 17, grounding switches 20
and 21 with one end of each of them connected to the grounding tank
1 are installed. In the bus classification unit 210, the current
breaking performance is required, so that SF.sub.6 gas 22 is
charged in the grounding tank 1 as insulating gas.
[0031] According to this embodiment described above, for the line
unit 190 having a switching unit, the bus connection unit 200, and
the bus classification unit 210, SF.sub.6 gas 22 which is superior
in the arc extinguishing performance from the viewpoint of
switching performance of large current and is conventionally used
is used and for the main bus units 100 and 110 including no
switching unit (the breaker 5, etc.) and the connection bus unit
160, gas having a smaller warming coefficient than that of SF.sub.6
gas 22, that is, nitrogen gas 23 contained in the atmosphere at a
rate of about 4/5, or air, is used.
[0032] The reason of appropriate use of insulating gas to be
charged into the grounding tank 1 of each unit as mentioned above
is that the GIS requires the high voltage insulation performance
and large current switching performance. With respect to the
insulation performance, several types of gases superior to SF.sub.6
gas have been found, while with respect to the arc extinguishing
performance controlling the current breaking performance, no gas
superior to SF.sub.6 gas is not found at present.
[0033] Recently, reduction of the GIS is progressing and a unit
having a switching unit is miniaturized. This is because the size
of the air outlet is decided by the atmospheric insulation and
hence the rate of the volume of the line bus portion connecting the
unit having a switching unit and the air outlet occupying the whole
volume of the GIS is increasing. Recently, the rate of the volume
of the line bus portion connecting the unit having a switching unit
and the air outlet occupying the whole volume of the GIS is 50% or
more.
[0034] Therefore, in this embodiment, since the GIS structured as
mentioned above appropriately uses insulating gas to be charged in
the grounding tank 1 of each unit, the amount of SF.sub.6 gas
occupying the GIS can be controlled to 50% or less unless the
current breaking performance originally requested to the GIS is
damaged. By doing this, the use amount of SF.sub.6 gas for earth
warming prevention which is in discussion at present can be
substantially reduced.
[0035] The dielectric strength of nitrogen gas is about 1/3 of that
of SF.sub.6 gas at the same pressure. Therefore, when nitrogen gas
is to be used at the same gas pressure as that of SF.sub.6 gas, it
is necessary to increase the insulation size of a unit charged with
nitrogen gas to about three times. This increase in the insulation
size will not cause an increase in the whole size of the GIS, so
that such a partial increase in size will not cause a big problem
in the GIS making progress in reduction.
[0036] When it is attempted to control the unit size to the same
size as that of the unit using SF.sub.6 gas, the pressure of
nitrogen gas is increased to about three times. In this case, it is
necessary to increase the thickness of the grounding tank 1 and
ensure the pressure resistance performance. However, the maximum
pressure is about 10 atmospheres and hence it is not a substantial
increase. The same may be said with a case that air is used.
[0037] FIG. 7 shows the essential portion of the insulating spacer
10. When a central conductor 2a in a grounding tank 1a of a unit
having a switching unit which is charged with SF.sub.6 gas 22 and a
central conductor 2b in a grounding tank 1b of a unit having no
switching unit which is charged with SF.sub.6 gas 23 are separated
from each other via an insulating spacer 10, a difference is often
caused between the pressure of the grounding tank 1a and the
pressure of the grounding tank 1b. The reason is that, as mentioned
above, SF.sub.6 gas and nitrogen gas are different in withstand
voltage and in such a combination of units, the pressure of
nitrogen gas is often increased, that is, the nitrogen gas 23 side
is higher in pressure than the SF.sub.6 gas 22 side. Therefore,
this embodiment uses the conical insulating spacer 10 and arranges
the units so that the convex 24 side thereof is the high pressure
side (the nitrogen gas 23 side) and the concave 25 side is the low
pressure side (the SF.sub.6 gas 22 side). Therefore, a use method
which is economically efficient and highly reliable can be applied
without increasing the strength of the insulating spacer.
[0038] Although not shown in the drawing, if a trouble should occur
in a unit having a switching unit inside the GIS, it is necessary
to collect SF.sub.6 gas charged in the grounding tank 1 of the unit
and recover the trouble. In this case, if the collection time is
longer though depending on the capacity of the collection tank, the
recovery may require a lot of time. Therefore, in this embodiment,
aiming at that nitrogen gas charged in the grounding tank of the
bus unit-which stops operation due to the trouble can be emitted
into the atmosphere, when the aforementioned condition is
generated, if the nitrogen gas charged in the grounding tank of the
bus unit is emitted into the atmosphere and the pressure in the
grounding tank is reduced or the grounding tank is evacuated, the
grounding tank may be used as a temporary SF.sub.6 gas collection
container. By this method, SF.sub.6 gas can be collected in a short
time, so that the trouble recovery time can be shortened.
Furthermore, the method does not let SF.sub.6 gas leak into the
atmosphere. Therefore, a highly reliable gas collection method can
be provided.
* * * * *