JP5239913B2 - Tank type vacuum circuit breaker - Google Patents

Description

  The present invention relates to a tank-type vacuum circuit breaker used for power transmission / distribution and power distribution facilities.

  As a conventional tank type vacuum circuit breaker, a pressure tank filled with dry air at a high gas pressure of about 0.4 to 0.5 MPa-g, and a vacuum valve (with a bellows installed at one end) Vacuum interrupter), the gas pressure in the outer peripheral area of the bellows and the gas pressure in the pressure tank are hermetically separated, and the gas pressure outside the bellows is maintained at atmospheric pressure, thereby reducing the differential pressure inside and outside the bellows. In some cases, the insulation between the vacuum valve and the pressure tank is ensured (see, for example, Patent Document 1).

JP 2007-306701 A (FIG. 1)

In the conventional tank type vacuum circuit breaker as described above, since a high gas pressure of about 0.4 to 0.5 MPa-g is applied to the pressure tank, a strong pressure tank such as increasing the thickness of the pressure tank is used. There is a problem that it is difficult to reduce the weight and cost of the apparatus. Moreover, since the dielectric strength of dry air is about 1/3 of SF ₆ gas, there is a problem that if the gas pressure in the pressure tank is lowered, the insulation performance in the pressure tank cannot be secured.

  The present invention has been made to solve the above problems, and provides a tank type vacuum circuit breaker that can reduce the gas pressure in the pressure tank while ensuring the insulation performance in the pressure tank. It is.

A tank type vacuum circuit breaker according to the present invention includes a pressure tank that is electrically grounded and having a plurality of openings, a current transformer tank that is connected to the openings and has a current transformer attached to the outside, and one end of the tank A bushing connected to the current transformer tank and hermetically sealed at the other end by a bushing terminal, and a first space provided between the pressure tank and the current transformer tank and formed in the pressure tank And a partition spacer made of an insulator that hermetically separates the current transformer tank and the second space formed in the bushing; an insulating gas sealed in the first space and the second space; A fixed valve and a vacuum valve that accommodates a movable conductor provided so as to be able to come into contact with and away from the fixed conductor; and the fixed conductor and the bushing provided through the partition spacer. A partition spacer comprising: a pair of lead conductors serving as a current path between the terminals and between the movable conductor and the bushing terminal; and an opening / closing means for driving the movable conductor via an insulating rod connected to the movable conductor. The creepage length on the first space side is longer than the creepage length on the second space side, the gas pressure in the first space is made lower than the gas pressure in the second space, and both end portions of the vacuum valve A pair of shields formed of a conductor in the first space outside the vacuum valve is further provided for the pair of lead conductors so as to cover the pair of lead conductors. It is electrically connected, and is electrically connected to the fixed conductor and the movable conductor via a pair of connection conductors provided for the pair of shields, and is in contact with the movable conductor. It said connecting conductors are to follow the movement of the movable conductor.

  According to the present invention, the gas pressure in the pressure tank can be reduced while ensuring the insulation performance in the pressure tank, so that the tank type vacuum circuit breaker can be reduced in weight and cost.

It is sectional drawing which shows the tank type vacuum circuit breaker in the form for implementing this invention. It is an expanded sectional view around a pressure tank among tank type vacuum circuit breakers in a form for carrying out the present invention. It is a side view which shows the state which arranged 3 units | sets of the tank type vacuum circuit breakers shown in FIG. It is a side view which shows the tank type vacuum circuit breaker in the other form for implementing this invention.

  FIG. 1 is a cross-sectional view showing a tank type vacuum circuit breaker in an embodiment for carrying out the present invention. FIG. 2 is an enlarged sectional view around the pressure tank in the tank type vacuum circuit breaker shown in FIG. 3 is a side view showing a state in which three units of the tank type vacuum circuit breaker shown in FIG. 1 are juxtaposed, and FIG. 4 is a side view showing a tank type vacuum circuit breaker according to another embodiment for carrying out the present invention. FIG. Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

  In FIG. 1 and FIG. 2, the electrically grounded pressure tank 2 is installed with the trunk portion horizontal, and a pair of openings 2 a and 2 b are provided above the pressure tank 2. A vacuum valve 3 is installed in the pressure tank 2 via a wall surface of the pressure tank 2 and a gap. The vacuum valve 3 includes a cylindrical vacuum vessel 31 made of an insulating material such as ceramic, and an end plate 32 that is housed in the vacuum vessel 31 and that has one end hermetically sealing the fixed-side end 31 a of the vacuum vessel 31. A fixed conductor 33 joined, and a movable conductor 35 that extends to the outside of the vacuum vessel 31 through a bellows 34 that is provided so as to be able to come into contact with and separate from the fixed conductor 33 and is attached to the movable side end 31b of the vacuum vessel 31; It consists of A fixed contact 33a and a movable contact 35a are formed at portions where the fixed conductor 33 and the movable conductor 35 are in contact with each other. Note that the end plate 32, the fixed conductor 33, and the movable conductor 35 are formed of a conductive material such as a copper alloy or an aluminum alloy, and the vacuum valve 3 is kept airtight in a vacuum.

  Opening / closing means 4 for opening / closing the fixed contact 33a and the movable contact 35a is provided outside the pressure tank 2. The opening / closing means 4 opens and closes the fixed contact 33a and the movable contact 35a by moving the movable conductor 35 in the horizontal direction via the operation rod 5 and the insulating rod 6. At this time, since the bellows 34 follows the movement of the movable conductor 35, the vacuum in the vacuum valve 3 is maintained. The insulating rod 6 is connected to the movable conductor 35 and the operating rod 5 while being electrically insulated. The connecting portion between the insulating rod 6 and the movable conductor 35 is described in, for example, Japanese Patent Application Laid-Open No. 2007-89356. By applying the configuration as described above, the space insulation performance between the movable conductor 35 and the pressure tank 2 and the insulator creepage insulation performance at both ends of the insulation rod 6 are improved.

A fixed shield 41 and a movable shield 51 are provided at both ends of the vacuum valve 3. The fixed-side shield 41 is disposed so as to cover the fixed-side end portion 31a of the vacuum valve 3, and the movable-side shield 51 covers the movable-side end portion 31b of the vacuum valve 3 and the end portion of the movable conductor 35. Has been placed. The fixed-side shield 41 and the movable-side shield 51 are made of a conductor material such as an aluminum alloy or a copper alloy, and the surfaces are formed as smooth surfaces without edges. As for the surface roughness of the smooth surface, it is desirable that the maximum height _Ry specified by JIS is approximately 12 μm or less. Further, an insulating coating film is formed on the surfaces of the fixed shield 41 and the movable shield 51 by a resin such as insulating rubber or epoxy, anodized, or powder insulation coating. The plate thickness of the fixed side shield 41 and the movable side shield 51 is about 6 mm, and the film thickness of the insulating coating is about 10 μm to 5 mm. In addition, although the fixed side shield 41 and the movable side shield 51 are configured in the same shape as in the present embodiment, the types of parts can be reduced, but the shapes of both members do not have to be the same. .
By providing the fixed side shield 41 and the movable side shield 51 in this manner, electric field concentration at the fixed side end 31a and the movable side end 31b of the vacuum valve 3 can be alleviated.

  Further, between the end plate 32 to which the fixed conductor 33 is joined and the fixed side shield 41, a fixed side connection conductor 42 for electrically connecting both members is provided, and the movable conductor 35 and the movable side shield 51 are connected. A movable side connection conductor 52 is provided between the two for electrically connecting the two. The movable side connection conductor 52 is made of a flexible conductor so as to follow the movement of the movable conductor 35, and the fixed side connection conductor 42 is made of a plate material. The fixed-side connection conductor 42 can also be formed of a block material having an adjusted elastic coefficient so as to absorb an impact at the time of opening / closing of the movable contact 33a and the fixed contact 35a.

  A fixed-side lead conductor 43 and a movable-side lead conductor 53 are provided above the fixed-side shield 41 and the movable-side shield 51, respectively. One end of the fixed-side lead conductor 42 and the movable-side lead conductor 52 is electrically connected to the fixed-side shield 41 and the movable-side shield 51, respectively, and the other end is connected to the pressure tank through the openings 2a and 2b of the pressure tank 2. 2 extends outside. The fixed-side lead conductor 42 and the movable-side lead conductor 52 are made of a solid conductive material, and projecting portions 43a and 53a are provided on the outer periphery thereof. As described above, the insulating coating film is formed on the surfaces of the fixed shield 41 and the movable shield 51, but the contact portion between the fixed shield 41 and the fixed lead conductor 43, and the movable shield 51 are also provided. In order to ensure electrical continuity, an insulating coating film is not formed at the contact portion between the lead wire 53 and the movable lead conductor 53. The fixed-side shield 41, the fixed-side connection conductor 42, and the fixed-side lead conductor 43 are fixed together by, for example, a bolt (not shown). The movable shield 51, the movable connection conductor 52, and the movable lead conductor 53 are fixed in the same manner.

  And the cylindrical current transformer tanks 44 and 54 which have a flange at both ends are connected to the opening parts 2a and 2b of the pressure tank 2, and the fixed-side connection conductor 43 and the movable-side connection conductor 53 have gaps, respectively. And are surrounded by the current transformer tanks 44 and 54. The current transformer tanks 44 and 54 are provided with a current transformer 7 for measuring the current flowing through the conductor.

  Further, bushings 45 and 55 are provided above the current transformer tanks 44 and 54, respectively. One ends of the bushings 45 and 55 are connected to the current transformer tanks 44 and 54, and the other ends are hermetically sealed by bushing terminals 45a and 55a. Hollow bushing-side lead conductors 46 and 56 are installed in the bushings 45 and 55, and are insulated in the air by the current transformer tanks 44 and 54 and the bushings 45 and 55. Further, the inner peripheral portions of the bushing-side lead conductors 46 and 56 are fitted to the outer peripheral portions of the fixed-side lead conductor 43 and the movable-side connection conductor 53, and both members are electrically connected. The other ends of the bushing side lead conductors 46 and 56 are electrically connected to the bushing terminals 45a and 55a, respectively.

  Partition spacers 47 and 57 are provided between the pressure tank 2 and the current transformer tanks 44 and 54, respectively. The first space 10 in the pressure tank 2, the current transformer tanks 44 and 54, and the bushing 45, The bushing-side lead conductors 46 and 47 surrounded by 55 are hermetically separated from the second space 20. A fixed-side lead conductor 43 and a movable-side lead conductor 53 penetrate through the central portions of the partition spacers 47 and 57, respectively, at positions corresponding to the protruding portions 43a and 53a of the fixed-side lead conductor 43 and the movable-side lead conductor 53, respectively. Indentations 47a and 57a are provided. Further, the partition spacers 47 and 57 are recessed in triple junctions 48 and 58 where the partition spacers 47 and 57, the fixed-side lead conductor 43, the movable-side lead conductor 53, and the insulating gas in the first space 10 are in contact. 47b and 57b are formed.

  Further, in order to ensure insulation on the first space 10 side where the gas pressure is lower than that of the second space 20, the creeping length on the first space 10 side of the partition spacers 47 and 57 is longer than the creeping length on the second space 20 side. Is provided. The creepage length on the first space 10 side is preferably 1.2 times or longer than the creepage length on the second space 20 side. An O-ring (not shown) for hermetically sealing the first space 10 and the second space 20 is provided between the partition spacers 47 and 57 and the current transformer tanks 44 and 54.

  In general, triple junctions where three different materials of metal / insulator / insulating gas are in contact with each other tend to cause local electric field concentration, and the insulation performance is likely to deteriorate. By providing the protrusions 43a and 53a on the conductor 43 and the movable-side lead conductor 53, respectively, the equipotential lines are smoothly spread and the electric field strength of the triple junction portions 48 and 58 is weakened. The dielectric breakdown from 58 is suppressed, and the dielectric strength can be improved.

  In addition, since the partition spacers 47 and 57 are formed with the recessed portions 47b and 57b in the triple junction portions 48 and 58, the electric field strength of the triple junction portions 48 and 58 can be further reduced. The dielectric breakdown from the portions 48 and 58 is further suppressed, and the dielectric strength can be improved.

  The partition spacers 47 and 57 are formed of a thermosetting resin such as an epoxy resin. A fixed-side lead conductor 43 having a protrusion 43a and a movable-side lead conductor 53 having a protrusion 53a are placed in the mold in advance during resin casting of the partition spacers 47 and 57, and these are formed by insert molding. In addition to forming recesses 47a and 57a to be fitted to the portions 43a and 53a, the partition spacers 43 and 53 are hermetically sealed between the fixed-side lead conductor 43 and the movable-side lead conductor 53.

  The first space 10 and the second space 20 are each filled with dry air having a moisture content of 10 ppm or less as an insulating gas, and the gas pressure in the first space 10 is higher than the gas pressure in the second space 20. It is also filled so as to be low. In the present embodiment, the maximum operating gas pressure in the first space is less than 0.2 MPa-g, and the gas pressure in the second space is 0.4 to 0.5 MPa-g, but the value is limited to this value. Not.

  As described above, in the tank type vacuum circuit breaker 1 according to the present embodiment, the creeping length on the first space 10 side and the creeping length on the second space 20 side of the partition spacers 47 and 57 are longer and smooth surfaces without edges. The fixed-side shield 41 and the movable-side shield 51 formed in the above are provided so as to cover both ends of the vacuum valve 3, and the electric field in the space between the fixed-side shield 41 and the movable-side shield 51 and the pressure tank 2, and the vacuum valve 3. The generated electric field on the creeping surface of the insulator can be reduced so as to be within the generated electric field that can be insulated and maintained in dry air of less than 0.2 MPa-g.

In addition, since the dry air pressure in the first space 10, that is, the pressure tank 2 is less than 0.2 MPa-g, the strength of the pressure tank 2 can be lowered, and the pressure tank 2 can be thinned or a reinforcing member for the pressure tank 2 can be provided. Since it can reduce, the weight reduction and cost reduction of an apparatus can be achieved.
Furthermore, since the gas pressure in the pressure tank 2 is set to less than 0.2 MPa-g, it is not necessary to undergo the second type pressure vessel test.

  Further, since the pressure difference between the inside and outside of the bellows 34 in the vacuum valve 3 can be reduced by reducing the gas pressure in the pressure tank 2, the bellows need not be reinforced, and a general-purpose structure can be used.

  Further, in the conventional tank type vacuum circuit breaker disclosed in Patent Document 1, the gas pressure in the peripheral area outside the bellows and the gas pressure in the pressure tank are hermetically separated, and the gas pressure outside the bellows is maintained at atmospheric pressure. Therefore, the seal member is provided in contact with the conductor whose temperature rises to a maximum of 115 ° C., and it is necessary to use an expensive seal member having high heat resistance. 1, the gas pressure in the pressure tank 2 can be made uniform, and it is not necessary to provide the seal member in contact with the conductor as in the prior art, so that it is not necessary to use an expensive seal member.

  Further, in the conventional tank type vacuum circuit breaker, since the seal member is provided in contact with the movable member in order to keep the gas pressure outside the bellows at atmospheric pressure, the fixed contact and the movable contact in the vacuum valve are provided. However, in the tank-type vacuum circuit breaker 1 according to the present embodiment, the fixed contact 33a in the vacuum valve 3 and Since the operating force required to open / close the movable contact 35a can be reduced, the opening / closing means 4 can be reduced in size.

In the present embodiment, dry air is used as the insulating gas sealed in the first space 10 and the second space 20, but the insulating gas is not limited to dry air, and nitrogen or carbon dioxide. Carbon or the like can also be used. Moreover, the gas pressure in the first space 10 can be further reduced by using SF ₆ gas having high insulation performance as the insulating gas.

  Since the tank-type vacuum circuit breaker 1 configured in this manner energizes a three-phase alternating current, the same tank-type vacuum circuit breaker 1 is placed on a gantry 60 having a single operation unit 59 as shown in FIG. 3 units are arranged side by side, and the withstand voltage performance of the exposed portions of the bushing terminals 45a and 55a provided in each unit of the tank type vacuum circuit breaker is used. Thus, by using the same configuration for the three units, it is possible to share parts and assembly work.

  In the present embodiment, the vacuum valve 3 for one phase is housed in the pressure tank 2. However, as shown in FIG. 4, the interior of one pressure tank 21 having three pairs of openings is provided. The three-phase vacuum valve 3 is housed in the lead-out conductors 42, 43, 46, 47, the switching means 4, the current transformer tanks 44, 54, the bushings 45, 55, and the partition spacers 47, 57, respectively. The same effect as that of the present embodiment can also be obtained with the provided three-phase collective tank type vacuum circuit breaker. Further, by using the three-phase collective tank type vacuum circuit breaker in this way, the material constituting the pressure tank 21 can be reduced, and the assembly to the base plate 61 and the assembly to the pressure tank 21 are consolidated. can do.

  According to the present embodiment, the partition spacers 47 and 57 made of an insulator are provided between the pressure tank 2 and the current transformer tanks 44 and 54, and the space in which the dry air, which is an insulating gas, is sealed is the pressure tank. 2 is hermetically separated into the first space 10 in the current transformer tanks 44 and 54 and the second spaces in the bushings 45 and 55, and the creepage length of the partition spacers 47 and 57 on the first space 10 side is While providing longer than the creeping length on the space 20 side, the gas pressure in the first space 10 is lower than the gas pressure in the second space 20, thereby ensuring the insulation performance in the pressure tank 2, while maintaining the insulation performance in the pressure tank 2. The gas pressure can be reduced.

  Further, according to the present embodiment, since the fixed side shield 41 and the movable side shield 51 provided so as to cover both end portions of the vacuum valve 3 are further provided, the insulation performance can be improved.

  Further, according to the present embodiment, the protrusions 43a and 53a are formed on the outer circumferences of the fixed-side lead conductor 43 and the movable-side lead conductor 53, respectively, and the protrusions 43a and 53a are covered with the partition spacers 47 and 57, respectively. In addition, the dielectric strength can be further improved.

  Further, according to the present embodiment, the partition spacers 47 and 57 have the recessed portions 47b and 57b in the triple junction portions 48 and 58 where the lead conductors 43 and 53 and the insulating gas in the first space 10 come into contact. Since it is formed, dielectric breakdown from the triple junction can be suppressed.

  Further, according to the present embodiment, the vacuum valve is obtained by forming the coating film made of an insulator on the surfaces of the fixed side shield 41 and the movable side shield 51 on the fixed side lead conductor 43 and the movable side lead conductor 53 side. 3 Electric field concentration at both ends can be alleviated.

  Further, according to the present embodiment, the pair of lead conductors are divided into the fixed lead conductor 43 and the bushing lead conductor 46, and the movable lead conductor 53 and the bushing lead conductor 47, respectively. Assembling of the vacuum circuit breaker 1 is facilitated.

Further, according to this embodiment, it is possible to global warming compared to SF ₆ gas which have been conventionally used since the dry air is zero is used as an insulating gas, to suppress the global warming.

  According to another embodiment, the vacuum valve 3 for three phases is accommodated in one pressure tank 21, the lead conductors 42, 43, 46, 47, the opening / closing means 4, the current transformer tank 44, 54, bushings 45 and 55, and partitioning spacers 47 and 57, each of which has a three-phase tank type vacuum circuit breaker, can reduce the material constituting the pressure tank 21, Assembly to the plate 61 and assembly to the pressure tank 21 can be integrated.

DESCRIPTION OF SYMBOLS 1 Tank type vacuum circuit breaker, 2 Pressure tank, 2a, 2b Opening part, 3 Vacuum valve, 4, Opening / closing means, 6 Insulating rod, 7 Current transformer, 10 1st space, 20 2nd space, 31a Fixed side end 31b Movable side end, 33 Fixed conductor, 35 Movable conductor, 41 Fixed side shield, 42 Fixed side connection conductor, 43 Fixed side lead conductor, 43a, 53a Protruding part, 44, 54 Current transformer tank, 45, 55 Bushing 45a, 55a Bushing terminal, 46, 47 Bushing side lead conductor, 47, 57 Partition spacer, 47b, 57b Recessed part, 48, 58 Triple junction part, 51 Movable side shield, 52 Movable side connection conductor.

Claims (9)

A pressure tank electrically grounded and having a plurality of openings;
A current transformer tank connected to the opening and having a current transformer attached to the outside;
A bushing having one end connected to the current transformer tank and the other end hermetically sealed by a bushing terminal;
Insulation provided between the pressure tank and the current transformer tank and hermetically separating a first space formed in the pressure tank and a second space formed in the current transformer tank and the bushing. A compartment spacer comprising the body;
An insulating gas sealed in the first space and the second space;
A vacuum valve that is provided in the first space and houses a fixed conductor and a movable conductor provided so as to be able to come into contact with and away from the fixed conductor;
A pair of lead conductors that are provided through the partition spacer and serve as a current path between the fixed conductor and the bushing terminal and between the movable conductor and the bushing terminal;
Opening and closing means for driving the movable conductor via an insulating rod connected to the movable conductor;
The creeping length on the first space side of the partition spacer is longer than the creeping length on the second space side, and the gas pressure in the first space is made lower than the gas pressure in the second space ,
A pair of shields formed of a conductor in the first space outside the vacuum valve is further provided for the pair of lead conductors so as to cover both ends of the vacuum valve,
The pair of shields are electrically connected to the pair of lead conductors and electrically connected to the fixed conductor and the movable conductor via a pair of connection conductors provided for the pair of shields, respectively. And
The tank-type vacuum circuit breaker characterized in that the connection conductor connected to the movable conductor follows the movement of the movable conductor .   2. The tank type vacuum circuit breaker according to claim 1, wherein the current transformer tank, the bushing, the partition spacer, the vacuum valve, the lead conductor, and the opening / closing means are divided into one pressure tank. A tank-type vacuum circuit breaker characterized by being provided.   2. The tank type vacuum circuit breaker according to claim 1, wherein the current transformer tank, the bushing, the partition spacer, the vacuum valve, the lead conductor, and the opening / closing means are provided in one pressure tank. A tank-type vacuum circuit breaker characterized by being provided. 4. The tank-type vacuum circuit breaker according to claim 1, wherein the shield faces a creeping surface on the first space side which is longer than a creeping surface on the second space side of the partition spacer. 5. tank-type vacuum circuit breaker, characterized in that provided Te.   5. The tank-type vacuum circuit breaker according to claim 1, wherein the lead conductor has a protrusion on an outer periphery, and the protrusion is covered with the partition spacer. A tank type vacuum circuit breaker.   The tank-type vacuum circuit breaker according to any one of claims 1 to 5, wherein the triple junction portion where the partition spacer, the lead conductor, and the insulating gas in the first space are in contact with each other. A tank-type vacuum circuit breaker characterized in that a recess is formed.   The tank type vacuum circuit breaker according to any one of claims 1 to 6, wherein the shield has a surface on the lead conductor side covered with an insulator. Circuit breaker.   8. The tank type vacuum circuit breaker according to any one of claims 1 to 7, wherein the lead conductor is divided into a plurality of parts.   The tank type vacuum circuit breaker according to any one of claims 1 to 8, wherein the insulating gas is dry air.

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