U.S. patent application number 11/197585 was filed with the patent office on 2006-02-23 for vacuum insulated switchgear.
Invention is credited to Masato Kobayashi, Takuya Kurogi, Ayumu Morita, Kenji Tsuchiya.
Application Number | 20060037944 11/197585 |
Document ID | / |
Family ID | 35207686 |
Filed Date | 2006-02-23 |
United States Patent
Application |
20060037944 |
Kind Code |
A1 |
Morita; Ayumu ; et
al. |
February 23, 2006 |
Vacuum insulated switchgear
Abstract
A vacuum insulated switchgear comprising: a vacuum container; a
vacuum insulated switch having a movable contact connected to a
movable electrode and a fixed contact connected to a fixed
electrode for interrupting and closing current; an operating rod
connected to the movable electrode and connected to a magnetic
drive mechanism; and a connecting mechanism for operating the
operating rod; the vacuum container, wherein the magnetic drive
mechanism and the connecting mechanism are aligned on a straight
line, wherein each of the magnet drive mechanisms has a shape of a
rectangular parallelopiped shape.
Inventors: |
Morita; Ayumu; (Hitachi,
JP) ; Tsuchiya; Kenji; (Hitachi, JP) ; Kurogi;
Takuya; (Hitachi, JP) ; Kobayashi; Masato;
(Hitachi, JP) |
Correspondence
Address: |
MATTINGLY, STANGER, MALUR & BRUNDIDGE, P.C.
1800 DIAGONAL ROAD
SUITE 370
ALEXANDRIA
VA
22314
US
|
Family ID: |
35207686 |
Appl. No.: |
11/197585 |
Filed: |
August 5, 2005 |
Current U.S.
Class: |
218/140 |
Current CPC
Class: |
H01H 31/003 20130101;
H01H 33/6662 20130101; H02B 13/0354 20130101; H01H 2033/6668
20130101; H01H 33/022 20130101; H01H 33/027 20130101; H01H 33/666
20130101 |
Class at
Publication: |
218/140 |
International
Class: |
H01H 33/66 20060101
H01H033/66 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 17, 2004 |
JP |
2004-237382 |
Claims
1. A vacuum insulated switchgear comprising: a vacuum container; a
vacuum insulated switch having a movable contact connected to a
movable electrode and a fixed contact connected to a fixed
electrode for interrupting and closing current; an operating rod
connected to the movable electrode and connected to a magnetic
drive mechanism; and a connecting mechanism for operating the
operating rod; the vacuum container, wherein the magnetic drive
mechanism and the connecting mechanism are aligned on a straight
line, wherein each of the magnet drive mechanisms has a shape of a
rectangular parallelopiped shape.
2. The vacuum insulated switchgear according to claim 1, wherein
the magnetic drive mechanisms are located above the respective
vacuum switches and the connecting mechanisms are located above the
respective magnetic drive mechanisms.
3. The vacuum insulated switchgear according to claim 1, wherein
each of the driving mechanisms comprises a plurality of plungers
connected to the upper end of each of the driving rods and a
magnet, and a spring for driving the plungers.
4. The vacuum insulated switchgear according to claim 1, wherein
each of the vacuum containers is of rectangular parallelopiped, the
switches are arranged side by side in the vacuum containers, the
driving mechanisms are arranged in positions corresponding to the
respective switches and being adjacent to the respective
electro-magnetic driving units, and the magnets of the
electro-magnetic driving units are of rectangular shape.
5. The vacuum insulated switchgear according to claim 1, wherein
the vacuum insulated switches include a vacuum circuit breaker, a
load break switch and an earthing switch.
6. The vacuum insulated switchgear according to claim 1, wherein
each of the connecting mechanisms has an interlock mechanism for
restricting the opening of the vacuum circuit breaker and the earth
switch.
Description
CLAIM OF PRIORITY
[0001] This application claims priority from Japanese application
serial No. 2004-237382, filed on Aug. 17, 2004, the content of
which is hereby incorporated by reference into this
application.
FIELD OF THE INVENTION
[0002] The present invention relates to a fully vacuum insulated
type vacuum switchgear, and more particularly to a technology for
space saving and improving assembly of a vacuum insulated
switchgear.
RELATED ART
[0003] Vacuum switchgears are used in power transmission lines,
which are called metal-clad type switchgears. The switchgears as
disclosed in patent document No. 1 comprise a metal box which
accommodates vacuum circuit breakers for interrupting load current
or failure current. The metal-clad type switchgear are provided
with a disconnector and an earth switch for securing safety of
operators at the time of inspection and/or maintenance of the load,
detectors for line voltage or current, protection relays, etc.
[0004] Though there various types of insulation systems for vacuum
switchgears, in fully vacuum insulated switchgears, an earthed
vacuum container encloses a plurality of switches, such as a
circuit breaker, a disconnecting switch, a load break switch and/or
earthing switch, so that the vacuum switch portion is remarkably
downsized.
Patent Document No. 1: Japanese Patent Laid-Open 2000-268686
[0005] The plural switches are enclosed in a single vacuum
container to downsize the switchgear; in order to downsize the
vacuum switchgear system, driving mechanisms for driving the
respective switches should be downsized.
[0006] As the switchgear is downsized, operation efficiency of
assembly and inspection and/or maintenance decreases, in general.
Accordingly, switchgears that do not hinder the operation
efficiency or assembly efficiency are desired.
SUMMARY OF THE INVENTION
[0007] The present invention aims at saving installment area of the
vacuum switchgear by downsizing it, without decreasing efficiency
of assembly and maintenance operation.
[0008] A vacuum insulated switchgear of the present invention
comprises a plurality of vacuum insulated switchgear modules; each
comprising, [0009] a vacuum container; [0010] a vacuum insulated
switch having a movable contact connected to a movable electrode
and a fixed contact connected to a fixed electrode for interrupting
and closing current; [0011] an operating rod connected to the
movable electrode and connected to a magnetic drive mechanism; and
[0012] a connecting mechanism for operating the operating rod; the
vacuum container, wherein the magnetic drive mechanism and the
connecting mechanism are aligned on a straight line, wherein the
magnet drive mechanism has a shape of a rectangular parallelopiped
shape.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side cross sectional view of an inside structure
of a vacuum insulated switchgear of one embodiment according to the
present invention.
[0014] FIG. 2 is a single line-wiring skeleton of the vacuum
insulated switchgear of the first embodiment shown in FIG. 1.
[0015] FIG. 3 is a front view of the vacuum insulated switchgear of
the first embodiment shown in FIG. 1.
[0016] FIG. 4 is a side view of the inner structure of the first
embodiment.
[0017] FIG. 5 is a top view of the magnet drive unit for explaining
the operation mechanism.
[0018] FIG. 6 is a cross sectional view of an electro-magnet for
explaining the structure of the electro-magnet.
[0019] FIG. 7 is a diagrammatic view of an electro-magnet for
explaining the operation.
[0020] FIG. 8 is a diagrammatic view of another example of the
electro-magnet for explaining the operation.
[0021] FIG. 9 is a diagrammatic view of a further example of the
electro-magnet for explaining the operation.
[0022] FIG. 10 is a top view of a connecting unit for switch
contacts of a part of the three phase vacuum insulated
switchgears.
[0023] FIG. 11 is a side view of the switchgears shown in FIG.
10.
EMBODIMENTS FOR PRACTICING THE INVENTION
[0024] The present invention provides a vacuum insulated switchgear
comprising a plurality of a single phase vacuum switchgear modules
each comprising a vacuum container, a vacuum switch in which switch
contacts and operating rods for driving the switch contacts and
magnetic drive mechanism each having driving rods for driving the
operating rods by electro-magnetic force and a spring force in
upward and downward directions. The magnetic drive mechanisms are
mounted above the vacuum switch components.
[0025] That is, the vacuum switch mechanisms section and the
magnetic drive mechanisms are stacked in two stages thereby to save
the installment area and downsize the switchgear. Since each of the
three phases is formed into a module, assembly, inspection and/or
maintenance of the switchgear can be conducted for each of the
single phase modules. Therefore, in constituting the three phase
vacuum switchgear system, efficiency of assembly, inspection and/or
maintenance is not lowered.
[0026] The present invention can be applied to a case where a
plurality of switch contacts such as a vacuum circuit breaker, a
load break switch, an earthing switch, etc is accommodated in a
single vacuum container. For example, movable contacts of the
vacuum circuit breaker and the load break switch are commonly
connected, and earthing switches for earthing fixed contacts of the
vacuum circuit breaker and the load break switch are enclosed in
the single vacuum container. In this case, the plural switches are
arranged side by side in the vacuum container, and a plurality of
magnet drive components is disposed side by side above the
corresponding switches.
[0027] Particularly, the vacuum container is formed in a
rectangular parallelopiped; the plural switch components are
arranged in the vacuum container in a straight line. The plural
drive mechanisms for driving the switch contacts are arranged in
accordance with the switch contacts. Each of the drive mechanisms
comprises a plurality of plungers connected to the upper end of the
driving rods and a magnet and spring for driving the plungers
upward and downward. In this case, by forming the outer shape of
the drive members, it is possible to utilize the installment space
effectively and a necessary magnetic force is generated in a small
install area.
[0028] On the other hand, the switching operation of the earthing
switches for earthing the contacts of the vacuum circuit breakers
is carried out in such a manner that the operation direction of the
earthing switches is opposite to that of the contacts of the vacuum
circuit breakers by electrically interlocking the drive mechanisms.
In addition to the electrical interlocking, a mechanical
interlocking mechanism is required from the view-point of safety.
In this case, connecting mechanisms components for limiting the
switching of the vacuum circuit breakers and the earthing switches
is mounted above the magnetic drive mechanisms.
[0029] Each of the interlock mechanisms of the connecting
mechanisms comprises a shaft extending horizontally a distance
between the driving rods for driving the vacuum circuit breakers
and earthing switches, two levers rotatably supported to the shaft,
two pins connecting one ends of the driving rods of the vacuum
circuit breakers and the earthing switches, and limiting members,
connected to the other end of the levers, for limiting the swing
movement of the other lever in the closing direction of the closing
of the vacuum circuit breakers and the earthing switches.
[0030] By disposing three vacuum switchgear modules for three
phases of the present invention in the single vacuum container of
the metal-clad type switchgear, the three-phase vacuum insulated
switchgear system can be easily assembled. In this case, switching
operation of the vacuum circuit breakers, load break switches,
disconnecting switches, etc must be synchronized. It is preferable
that the switches are not only electrically synchronized, but also
mechanically synchronized.
[0031] It is preferable to dispose the connecting mechanisms for
securing three-phase synchronous operation of the vacuum
switchgears. In this case, the basic concept of the single-phase
module is maintained. In the connecting mechanisms of the present
invention, the connecting mechanism s are constituted by a shaft
extending in the direction transversing the direction of
arrangement of the single phase modules for three phases, and
levers rotatably connecting by means of pins to the driving members
connected to one end of the driving rods, wherein the adjoining
connecting units in three phase arrangement are connected by means
of extensible links to the connecting rods, which are connected to
the pins to the other ends of the levers
[0032] As a result, if the three drive levers for driving the
switches of each phases are connected, the operation of the
respective switches are synchronized. However, since it is
impossible to avoid assembling errors of the switches and the drive
mechanisms, and other manufacturing error, the operation of the
respective switches should be adjusted in accordance with the
errors when assembling the single phase modules.
[0033] In the present invention, the drive levers of the adjoining
single modules are connected by means of extensible links to the
connecting rods. That is, by extending or contracting the links to
substantially adjust the length of the connecting rods, whereby the
displacement of synchronous operation is absorbed. As a result, the
three modules can operate synchronously.
[0034] Particularly, compared with the case where the three drive
levers are connected in a line by a single connecting rod, since
the adjoining drive levers are connected by a connecting rod, the
position precision of the drive levers becomes loose.
[0035] According to the present invention, it is possible to
downsize vacuum switchgears with a small installment space without
decreasing efficiency of assembly, inspection and/or
maintenance.
[0036] As shown in FIG. 2, each phase of the vacuum switchgear 1 of
the present embodiment comprises a single circuit breaker CB, two
load break switches LBS, and three earthing switches ES. The
present invention is not limited to the embodiment shown in FIG. 2.
The present invention can be applied to a case where there is a
plurality of circuit breakers or to a case where there is a
disconnecting switch I addition to the other switches. In FIG. 2,
the fixed contacts of the circuit breaker CB and load break switch
LBS are connected to the cable 4, which are extended to outside of
the vacuum container. The movable contacts of the circuit breaker
CB and the load break switch LBS are commonly connected to a bus
71. Each of the cables 4 is provided with a voltage detection
sensor VDS, and the cable 4 of the circuit breaker CB is provided
with a circuit transformer CT.
[0037] FIG. 1 is a side view of a vacuum switchgear 1 of the preset
invention, which shows three switchgears for three phases. As shown
in FIG. 1, the vacuum switchgear 1 comprises a protection relay 2
disposed to a door of the metal clad box, a condenser 3 used as a
power source of the magnetic drive unit, a cable 4 for connecting
the power source side and the load side, a measuring transformer 5
for measuring current and a voltage detector VD12.
[0038] The vacuum switch means 6 each having a plurality of switch
contacts are constituted by three vacuum containers 60 each being
separated for each phase. Magnetic drive mechanisms 8 for driving
the plural switch contacts are mounted above the vacuum containers
60, and connecting mechanisms 9 as link mechanisms for securing
operation synchronism of the three phase contacts are mounted above
the magnetic drive units 8 to constitute a three stage stack
structure.
[0039] The inside of the vacuum switchgears can be inspected or
maintained by turning the handle 10 to open the front door 11. The
vacuum containers 60 accommodate a plurality of switch contacts
shown in FIG. 2.
[0040] The reason why the vacuum containers 60 are separated for
each phase is to avoid a serious accident caused by accidental
excess current by limiting a trouble of one of the vacuum
containers such as vacuum leakage to a single line earthing
failure.
(Vacuum Switch Unit)
[0041] Next, the structure of the vacuum switch unit 6 will be
explained by reference to FIGS. 3 and 4. FIG. 3 is a front view of
the inner structure of the vacuum switchgear 1 and FIG. 4 is a side
view of the inner structure of the vacuum switchgear. The vacuum
container 60 is fixed to a base 20 by a fixing leg portion 22 shown
in FIG. 1 with a bolt-nut 21. The bases 20 are separated from each
other for the respective vacuum containers 60. The bases 20 are
fixed separately. The three vacuum containers have the same
structure, which are kept at the ground voltage. As a result, if an
operator touches the vacuum container during the operation of the
vacuum switchgear 1, the safety is secured.
[0042] Three cable connecting portions 23 made of ceramics protrude
from the vacuum containers 60, into which cables 4 are inserted
respectively. The cable connecting portions 23 are provided with
feeders 24, which are fixed to conductive plates 25. The cable
connecting portions 23 are fixed to the vacuum containers 60 by
means of members 50 and connected to the conductive plates 25 by
means of the members 51 to establish vacuum tightness.
[0043] The fixed conductors 26 connected to the fixed contacts 27
of the circuit breakers, the fixed conductors 39 connected to the
fixed contacts of the earthing switch 40 and the insulating
supporters 37 connected to the members 36 are fixed to the
conductive plates 25. The insulating supporters 37 are fixed to the
vacuum container 60 by means of the members 36. The members are
fixed by blazing in vacuum.
[0044] The members 51, 36, 38 to be blazed with the cable
connecting portions 23 or the insulating supporters 37 have
recess-and-projections 61 to relieve residual stress after
blazing.
[0045] The vacuum circuit breaker CB has the fixed contact 27 and
the movable contact 28 in opposite relation to each other. Opening
and closing of the contacts make the circuit open and close. The
movable contact 28 is connected to the movable conductor 29 by
blazing. The movable conductor 29 is strengthened by an operating
rod 30 made of stainless steel.
[0046] The operating rod 30 is sandwiched by members 31, 32 for
alleviating blazing stress and connected to the insulating
supporter 32. The operating rod 30 is connected to the connecting
member 35 of the magnetic operating mechanism 8 by means of the
member 33. The member 33 is connected to a bellows 34, which is
connected to the vacuum container 60 at its other end, whereby the
movable contact 28 moves up and down, keeping vacuum.
[0047] The flexible conductor 70 connected to the movable conductor
29 is connected to a bus 71. The flexible conductor 70 is a
laminate of thin copper plates. The flexible conductor 70 makes a
stable current flow even when the movable contact moves. As shown
in FIG. 3, the bus 71 is connected to the movable conductor of the
load break switch LBS, to constitute the wiring shown in FIG.
2.
[0048] An arc shield 73 fixed to the ceramic cylinder 72 is formed
Around the fixed contact 27 and the movable contact 28. The ceramic
cylinder 72 is fixed to the current plate 25 by means of a residual
stress relieving member 75 at its end. The other end of the ceramic
cylinder 72 is connected to the bus 71 by means of the residual
stress relieving member 76 and a case 74. That is, the current
plate 25, the residual stress relieving members 75, 76, ceramic
cylinder 72 and the case 74 constitute a space for the circuit
breaker. This structure prevents lowering of withstanding voltage
performance of the contacts 27, 28 by scattering and contamination
of the inner face of the ceramic cylinder with metallic particles
from the contacts at the time of interruption. The arc shield 73
prevents contamination of the inner face of the ceramic cylinder 72
with metallic particles.
[0049] On the other hand, the earthing switch ES is provided with
the movable contact 41 in opposite relation to the fixed contact
40; when the contacts are closed, earthing of the circuit is
conducted. The movable contact 41 is connected to the movable
electrode 42, which is provided with as a center rod the operating
rod 44 made of stainless steel for strengthening the movable
electrode 42. The operating rod 44 is fixed to the connecting
member 48 of the magnetic drive mechanism by means of the
insulating supporter 46 and the residual stress relieving member
45, 47.
[0050] The shield 77 is disposed to surround the fixed contact 40
and the movable contact 41 is not needed under the normal
operation, but if the contacts are accidentally closed during
current flow in the main circuit, the shield 77 prevents a
preceding arc to scatter outside the vacuum container, which leads
to lowering of the withstanding voltage property.
[0051] The movable electrode 42 is connected with the flexible
conductor 43, which is fixed to the earthing bus 78. As shown in
FIG. 3, the movable contact 42 of the earthing switch ES is also
connected to the bus 78 by means of the flexible conductor 43, the
bus 78 being connected outside the vacuum container by means of the
feeder.
[0052] As shown in FIG. 4, a space S2 is formed by a case 79 to
surround the flexible conductor 43. Since the flexible conductor 43
is formed of laminated thin copper plates, minute copper particles
may be generated by sliding the copper plates at the time of
switching operation. An area where the particles scatter must be
confined in the space S2 so as to avoid lowering of insulation
reliability. The space S for the circuit breaker has the similar
function.
[0053] As having been described, by integrating the plural switches
in the vacuum container, the switchgear can be downsized; further,
since the length of the conductor is shortened, current flow loss
can be minimized. As is shown in the above embodiment, by
separating the vacuum containers 60 for each phase, the failure is
limited to only one line even when a vacuum leakage accident
happens, thereby to suppress the accidental current.
(Magnetic Drive Unit)
[0054] Next, the magnetic drive mechanism 8 will be explained by
reference to FIGS. 3, 5 and 6. FIG. 3 is a front view of the vacuum
insulated switchgear shown in FIG. 1. FIG. 5 is a top view of the
magnetic drive mechanism 8, and FIG. 6 is a side view of the
magnetic drive mechanism 8.
[0055] The magnetic drive mechanism 8 comprises an electro-magnet
94 for driving each of the movable contacts in the vacuum circuit
breakers 94, a connecting unit 95, an interrupting spring 96 for
separating the contacts, and a pressing spring 97 for imparting a
contact force to the contacts. A driving mechanisms such as the
electro-magnet 94, etc of the magnetic drive mechanisms 8 are
arranged on a straight line with respect to the contacts and the
movable conductor connected to the contacts in the vacuum container
60. By connecting the contacts and electro-magnets 94 on a straight
line, shafts, levers, etc may be omitted. As a result, operation
energy can be saved and the capacity or size of the electro-magnet
94 and the condenser 3 as a power source can be downsized.
[0056] Further, in the above embodiment, since the vacuum container
60, the magnetic operation mechanism 8, and the connecting
mechanisms 9 are connected in order, the driving force of the
magnetic drive mechanism 8 is effectively transmitted to the
contacts in the vacuum container 60.
[0057] The connecting mechanism 95 comprises an intermediate metal
98 for engaging with the shaft 102 of the electro-magnet 94 and a
pin 103, and a connecting member 100 fixed to the connecting member
35, which protrudes from the vacuum container. The interrupting
spring 96 is sandwiched between a spring holding metal 99 connected
to the intermediate metal 98 and the base 90; the interrupting
spring 96 is compressed at the same time when the plunger 110 of
the electro-magnet 94 is operated downward for closing the
contacts.
[0058] On the other hand, the contact spring 97 is sandwiched
between the spring holding metal 99 and connecting member 100.
Since the shape of the hole into which the pin 101 of the
intermediate metal 98 is inserted is elliptical, the connecting
member 100 moves together with the plunger 110 until the fixed
contact and the movable contact collide, and after collision, only
the upper parts above the intermediate metal 98 move thereby to
bias the contact spring 97 to impart a contact force to the
contacts.
[0059] A construction and operation principle of the electro-magnet
94 will be explained in the following. FIG. 5 is a top view of the
electro-magnet mechanism 8. The outer periphery of the
electro-magnet 94 is rectangular.
[0060] The inner structure of the electro-magnet 94 is explained by
reference to FIG. 6. FIG. 6 is a side cross sectional view of the
electro-magnet 94. The fixed iron core 120 comprises a lower steel
plate 121, a central leg 122, a rectangular steel pipe 123 and a
permanent magnet stage 124. The central leg 122 is fixed together
with the steel plate 125 by means of the lower steel plate 121 and
the bolt 126.
[0061] The movable iron core 130 comprises a movable flat plate 131
and a plunger 110, a non-magnetic shat 102 made of stainless steel,
etc penetrating the center of them. The permanent magnet 132 in
opposite relation to the movable flat plate 131 is disposed. The
permanent magnet 132 is fixed to the permanent magnet base 124 by
means of an adhesive.
[0062] There is a gap (g) between the movable flat plate 131 and
the permanent magnet 132 so that the permanent magnet 132 never
moves to the movable flat plate 131 side. A coil 133 is disposed in
the electro-magnet 94 to which exciting energy is supplied from the
condenser 3 shown in FIG. 1.
[0063] The rectangular steel pipe 123 is made of JIS-G3466 defined
as "rectangular pipe for general structural use", which is
standardized, so as to reduce a cost. At the same time, the plunger
110, the coil 133, the permanent magnet 131, the movable flat plate
131, etc are formed rectangular. As is apparent from FIG. 5, the
above-described structure has an improved space factor, compared
with the conventional round shape electro-magnet. At the same time,
the electro-magnet 94 is effectively arranged in accordance with
the size of width (W) and the depth (D) of the electro-magnet
94.
[0064] The electro-magnet 94 is assembled in the following manner.
At first, the lower steel plate 121 fixed with the bolt 126, the
steel plate 126 and the central leg 122 are placed on a hexagonal
portion 134a of the rectangular tube 134. The rectangular steel
pipe 123, the coil 133 and the permanent magnet 132 are stacked on
the permanent magnet table 124. They are fastened by the shaft 102
and a nut 111 to constitute the movable iron 130.
[0065] Finally, a permanent magnet cover 135 made of a rectangular
steel pipe as same as the rectangular steel pipe 123 and an upper
cover 135 are placed; then, they are fastened by the nut 137. As a
result, the members are sandwiched between the nut 137 and the
hexagonal portion 134a of the tube 134, whereby leakage of the
magnetic field outside the electro-magnet 94 is reduced and the
influence on the adjoining electro-magnets becomes negligible.
[0066] As shown in FIG. 3, the intermediate metal 98 is connected
to the assembled electro-magnet 94 by means of the pin 103, and the
tube 134 is fixed to the base 90, holding the interrupting spring
96 by the spring holding spring 99, the base 90 and the
strengthening plate 91. If this assembly is applied to the 6
electro-magnets 94 corresponding to the contacts in 1:1 in the
vacuum container, the magnet drive mechanism modules are obtained
140 shown in FIG. 5.
[0067] The operation principle of the electro-magnet 94 will be
explained by reference to FIGS. 7 to 9. FIG. 7, FIG. 8 and FIG. 9
show a closing operation, a retaining of closing operation, and an
opening operation, respectively. In the state of opened contacts,
if the coil 133 is excited, an attractive force by the magnetic
flux (fc) due to coil current is generated between the plunger 110
and the central leg 122 thereby to start to move the movable iron
core 130 in the direction of the downward in the figure.
[0068] With the operation of the movable iron core 130, the movable
contact in the connected vacuum container moves in the closing
direction. In the state immediately before completion of closing
operation, since the flux (fpm) of the permanent magnet starts to
act, an attractive force acts between the movable iron core 131 and
the permanent magnet 132.
[0069] As is described above, the electro-magnet has the attractive
force characteristics, which are equivalent to the spring force of
the contact spring 97 from the time of the collision of the
contacts in the vacuum container 60, wherein the spring force
becomes drastically increases from the time of collision.
[0070] When the closing operation is completed, magnetization of
the coil 133 is released as shown in FIG. 8 and the closing state
is maintained only by the attractive force of the permanent magnet
132. At this stage, the interrupting spring 96 and the contact
sprig 97 are biased to prepare for the opening operation. In the
opening operation, as shown in FIG. 9, current in a direction
opposite to that in the closing operation is supplied. At this
time, since the flux (.phi.c) by the coil current acts to cancel
the flux (.phi.pm) by the permanent magnet, the attractive force of
the electro-magnet 94 decreases. As a result, when the spring force
of the interrupting spring 97 and the contact spring 96 is larger
than that of the electro-magnet, the movable iron core 130 moves
upward in the figure to open the contacts of the switch.
[0071] Next, a method of connecting the vacuum container 60 and
electro-magnetic drive mechanism module 140 will be explained in
the following. As shown in FIGS. 3 and 4, the base 20 of the vacuum
container and the base 90 of the electro-magnetic drive mechanism
module 140 are separated from those of the other phase; therefore,
a single phase module 150 comprising the vacuum container 60 and
the electro-magnetic drive mechanism module can be constituted. For
example, the base 20 and the base 90 may be fixed by the connecting
member 92. That is, three of the phase modules 150 are arranged,
and the connecting means are disposed above the modules to
constitute the vacuum switchgear 1.
[0072] Connection between the electro-magnetic drive mechanism 8
and the connecting member 35 extending from the vacuum container 60
will be explained by reference to FIG. 3. The electro-magnet 94 is
in a closed position. The connecting member 100 and the nut 152 are
connected to the connecting member 35, the base 90 is fixed to the
connecting member 92 by means of the bolt 93, inserting the
intermediate metal 98 into the connecting member 100 under the
state that the contact spring 97 is inserted. At this time, the
connecting member 100 is screwed into the connecting member 35 as
much as possible so as to avoid the load of the contact spring
97.
[0073] After the above work is finished, the depth of screwing of
the connecting metal 100 is adjusted so as to impart a
predetermined load. After the adjustment, the pin 101 is screwed to
complete connection between the electro-magnetic operation
mechanism module 140 and the vacuum container 60 thereby to obtain
a single phase module.
[0074] The following adjustment and tests before shipment of the
module at the stage of the single phase module may be conducted. In
general, vacuum circuit breakers are shipped after breaking-in
operation followed by adjusting a contact spring load. The
breaking-in operation is that non-load switching operation is
repeated about 100 times, wherein the parallelism of the contacts
is forcibly improved by utilizing the impact force at the collision
of contacts.
[0075] Since the vacuum container 60 is assembled in a high
temperature vacuum oven, the mechanical strength of the respective
members are different from those at room temperature. Particularly,
the reduction in strength of the copper conductor used for current
flow is remarkable. For example, the movable conductor 29 and the
fixed conductor 26 are deformed in a shrinkage direction by the
impact force. By the breaking-in operation, the switching operation
is repeated until the deformation becomes saturated, and the
contact spring load is adjusted after the operation before
shipment.
[0076] In this embodiment, the breaking-in operation is conducted
at the stage of the single phase module. After the phase modules
150 are assembled into a three phase switchgear, it is impossible
to secure a space for work to adjust the contact spring load. In
other words, by making the phase module of the vacuum insulated
switchgear of the present invention, the space for adjustment is
not necessary and the switchgear can be downsized as a whole. That
is, the present invention aims not only at improving the working
efficiency, but also at downsizing the switchgear.
[0077] The withstanding voltage tests of the vacuum switch 6 can be
done at this stage. Since the vacuum container 60 of the vacuum
insulated switchgear 1 is earthed, the electric field distribution
in the container is not affected by other phases. If the
withstanding voltage test of the phase module 150 can be done,
attachment of cables 4 is easy and efficiency of the work
increases.
[0078] As having been explained, since the vacuum container 60 and
the electro-magnetic operation mechanisms 8 for driving the
contacts therein are made into a module for each phase, the
adjustment and various tests can be performed before shipment.
Therefore, a work efficiency increases, and it is necessary to
secure a space for the work; downsizing and cost down of the
switchgear will be expected.
(Connecting Mechanisms)
[0079] Next, the connecting means 9 for constituting the connecting
mechanism 9 for securing three-phase synchronism of the switching
operation will be explained by reference to FIGS. 10 and 11. FIG.
10 is a top view of the connecting means of a part of the switch
contacts for three phases, and FIG. 11 is its side cross sectional
view.
[0080] The connecting means 9 has a unit comprising a connecting
means 161 for the circuit breaker CB or the load break switch LBS
and a connecting means 160 for the earthing switch ES. There are
three units of connecting means in the vacuum insulated switchgear
1.
[0081] As shown in FIGS. 10 and 11, one of the units of the
connecting means comprises three main shafts 162, 164a, 164b, 164c,
levers 163a, 163b, 163c, 164a, 164b, 164c for rotating around the
shafts and connecting members 165a, 165b, 165c, 166a, 166b, 166c
for connecting the respective levers. The suffixes a, b and c
represent phase A, phase B and phase C, respectively. The levers
163a, 163b, 163c are of the circuit breakers CB or the load break
switches, and the levers 164a, 164b and 164c are of the earthing
switches ES.
[0082] The main axes 162a, 162b, 162c are fixed by the nuts 168
using brackets 167 for both sides. The brackets 167 are fixed to
the upper cover 136 of the electro-magnet 49 by means of bolts. The
lever 163a that rotates around the main shaft 162a is connected to
the shaft 102 of the electro-magnet 49 by means of the pin 169, the
intermediate link 170, the pin 172 and the connecting member
171.
[0083] The lever 163a is connected to the lever 163b of phase B by
means of pin 173 and the connecting member 165ab. The levers 163b,
163c of phase B and phase C are connected to the electro-magnet 49
and connected to the lever 163a of phase A. Connection of the
connecting means 160 of the earthing switch ES to the lever and the
electro-magnet 49 is the same as the above.
[0084] The main shafts 162a, 162b, 162c are located at the center
between the main shaft 102 of the electro-magnet for the circuit
breaker CB or the load break switch LBS and the shaft 102 of the
electro-magnet for the earthing switch ES. For example, the length
L of right side and left side in FIG. 11 should be equal. As a
result, the lever 163a, 163b, 164a, 164b, 164c and four connecting
members 165a, 165b, 165c, 165ab, 165bc, 166ab, 166bc are the
identical parts, which leads to the cost reduction.
[0085] A status indicator 181 shown in FIG. 11 is connected to the
lever 163a of the circuit breaker CB or the load break switch LBS
by means of the pin 180; the status indicator 181 is connected to a
operation number meter 182 by means of the spring 183. The operator
is able to know the status of the vacuum switchgear by the position
of the indicator. In synchronism with the connecting means 9, the
status display panel 181 and the operation number meter 182
operate. Further, the lever 163c is connected to the auxiliary
switch 184. This structure is the same as in the earthing switch
ES.
[0086] In driving the respective contacts independently, the status
display panel 181, the operation number meter 182 and the auxiliary
switch 184 have been disposed for each of the operation mechanisms
in the conventional switchgears. However, in the present
embodiment, which utilizes the connecting means 9, only one of each
element is needed for the whole switchgear. Wiring of the auxiliary
switch becomes simplified in this embodiment.
[0087] Operation of the connecting means 161 for the circuit
interrupter CB or the load break switch LBS will be explained by
reference to FIG. 11. In closing operation, since the movable iron
core 130 of the electro-magnet 49 moves downward, the levers 163a,
163b, 163c rotate in an anti-clockwise direction. According to
this, the connecting portions 165a, 165b, 165c move in the left
direction. Since a stop position is decided by the collision point
between the plunger 110 of the electro-magnet 49 and the central
leg 122, a stopper for the closing operation is not necessary for
the connecting means 161.
[0088] On the other hand, in opening operation of the contacts,
since the movable iron core 130 of the electro-magnet 49 moves
upward, the levers 163a, 163b, 163c rotate in a clockwise
direction. According to this, the connecting portions 165ab, 165bc
move in the right hand direction. A distance of opening operation
is adjusted by inserting an adjusting plate 191 between the stopper
bolt 190 and its seat 192; discrepancy between the phases is
adjusted by turn-buckles 193ab, 193bc, which are an extensible
connector, disposed to the connecting members 165ab, 165bc.
[0089] On the other hand, operation of the connecting means 160 for
the earthing switch ES is one opposite direction to that of the
connecting means 161, since the connecting means 160 is disposed at
the center position between the shaft 102 of the circuit breaker CB
or of the load break switch LBS and the shaft 102 of the
electro-magnet 49 of the earthing switch ES.
[0090] On the other hand, in opening operation, since the movable
iron core 130 moves upward, the levers 164a, 164b, 164c rotate in
an anti-clockwise direction, and the connecting members 166 as,
166bc move to the left hand. In the opening operation, the
connecting member 166bc collides with the stopper bolt 190 to
stop.
[0091] The reason why the operation direction of the connecting
means 160 of the earthing switch ES is set to be opposite to that
of the connecting means 161 of the circuit breaker CB or the load
break switch LBS is that the number of parts can be reduced and the
cost is reduced by parts sharing and that the mechanical interlock,
which will be explained in the following is realized.
[0092] That is, the link member 200 is connected with the lever
163c and the pin 169c; in the state that the circuit breaker CB or
the load break switch LBS is closed, the interlock pin 201 at the
other end side moves within the elliptic hole 203 of the guide 202.
At this status, if the earthing switch ES is tried to close,
operation is impossible because the lever 163c interferes the
interlock pin 201.
[0093] On the other hand, in the status where the earthing switch
ES is closed, since the interlock pin 204 has moved downward,
operation is impossible because the lever 162b interferes the
interlock pin 204, if the circuit breaker CB or the load break
switch LBS is closed.
[0094] As has been described, by making the operation directions of
the connecting means 161 of the circuit breaker CB or the load
break switch LBS and the connecting means 160 of the earthing
switch ES opposite to each other, a mechanical interlock is easily
realized to limit the swing of the connecting means in the closing
directions, because the positions of the levers 163, 164 coincide
with each other when one of the switches is in the closed
state.
[0095] The main shaft 162 is shared for the connecting means, which
aims at securing the three phase synchronism of the contacts
according to the embodiment, for the circuit breaker CB or the load
break switch LBS or the connecting means for the earthing switch
ES, whereby the number of parts is reduced and a cost is lowered.
Further, since the operation directions of the two are opposite to
each other, a mechanical interlock is easily realized to improve
safety and reliability.
[0096] As is explained above, the vacuum insulated switchgear 1 has
a three stage stack of the vacuum switch 6, the magnetic operation
mechanism 8 for independently driving the contacts in the vacuum
container 6 and the connecting means 9 for securing the three phase
synchronism of the switching operations; the installment area of
the vacuum insulated switchgear is minimized to realize the compact
and low cost switchgears. At the same time, the vacuum switch 6,
the electro-magnetic operation mechanism 8 and the connecting means
9 are downsized.
[0097] The vacuum container 6 accommodates a plurality of switches
having functions of the circuit breaker, the disconnecting switch,
the load break switch or the earthing switch to make the switchgear
compact.
[0098] The magnetic operation mechanism 8 utilizes rectangular
steel pipes for the fixed iron cores to increase the space factor
of the electro-magnet 94.
[0099] The magnetic operation mechanism 8, the contacts and the
movable conductor fixed to the contacts are aligned on a straight
line to omit parts such as shafts, levers for shifting the movement
directions.
[0100] The switchgear of the present invention lowers a loss of
operation energy to downsize the electro-magnet 94 and the
condenser 3 as a power source.
[0101] Since the vacuum insulated switch 6 and the electro-magnetic
operation mechanism 8 are formed into a module for each phase,
adjustment and testing of the phase modules can be done before
shipment to increase work efficiency. Further, it is not necessary
to keep a space for the work.
[0102] The connecting means 9 makes a unit comprising the
connecting means 161 for the circuit breaker, the disconnecting
switch or the load break switch and the connecting means 160 for
the earthing switch to thereby reduce the number of parts. The
number of parts is reduced by sharing.
[0103] By arranging the main shafts 162a, 162b, 162c and levers
163a, 163b, 163c, 164a, 164b, 164c as in the present embodiment, a
mechanical interlock is easily realized to improve safety and
reliability.
* * * * *