JP5475538B2 - Vacuum circuit breaker - Google Patents

Description

  Embodiments of the present invention relate to a vacuum circuit breaker equipped with a vacuum valve that can improve partial discharge characteristics.

  Conventionally, in a vacuum circuit breaker, a vacuum valve having a pair of contactable contacts is fixed to an insulation barrier, and insulation performance is maintained by the insulation barrier (see, for example, Patent Document 1). ).

  As shown in FIG. 6, this type of vacuum circuit breaker includes an upper main circuit conductor 2 and a lower flange respectively provided on an upper flange portion 1a and a lower flange portion 1b of an insulating barrier 1 having a U-shaped cross section molded with an epoxy resin or the like. The main circuit conductor 3 is fixed with bolts 4. A vacuum valve 5 having a pair of contactable and separable contacts is provided between the main circuit conductors 2 and 3, and the fixed side is fixed to the upper main circuit conductor 2. A movable energizing shaft 6 passes through the lower main circuit conductor 3, and a middle portion between the lower main circuit conductor 3 and the movable energizing shaft 6 is connected by a flexible conductor 7. An insulating operating rod 8 is connected to the movable side energizing shaft 6, and is connected to an operating mechanism 10 that opens and closes the vacuum valve 5 via an operating lever 9.

Japanese Patent Laying-Open No. 2006-238581 (Page 4, FIG. 1)

  The above-described conventional vacuum circuit breaker has the following problems. Although the main circuit conductors 2 and 3 are fixed on the surface of the insulation barrier 1, it is difficult to completely remove the unevenness existing on the surfaces of the insulation barrier 1 and the main circuit conductors 2 and 3. In particular, in the insulating barrier 1, unevenness of several μm to several hundred μm is formed depending on the temperature control during molding.

  If a minute gap is formed between the insulating barrier 1 and the main circuit conductors 2 and 3, the electric field distribution is disturbed and partial discharge occurs, making it difficult to increase the voltage of the vacuum breaker, which is a recent trend. For this reason, even if unevenness is formed on the surface of the insulating barrier 1, it has been desired to suppress the occurrence of partial discharge and enable high voltage. In addition, when partial discharge occurs, insulation deterioration progresses, and finally dielectric breakdown is reached.

  Embodiments of the present invention have been made to solve the above-described problem, and an object of the present invention is to provide a vacuum circuit breaker capable of suppressing a partial discharge generated between a main circuit conductor and an insulating barrier and increasing the voltage. And

In order to achieve the above object, a vacuum circuit breaker according to an embodiment of the present invention includes a vacuum valve having a pair of contactable contacts, a main circuit conductor connected to the main circuit of the vacuum valve, and the main circuit conductor. A vacuum circuit breaker having a flange portion of an insulating barrier to which a circuit conductor is fixed and an operation mechanism for opening and closing the vacuum valve, and a chamfered portion is provided at the end of the main circuit conductor in contact with the flange portion , A plurality of grooves are provided in the main circuit conductor surface in contact with the flange portion .

The principal part expanded sectional view which shows the structure of the vacuum circuit breaker which concerns on Example 1 of this invention. The figure explaining the partial discharge characteristic of the vacuum circuit breaker which concerns on Example 1 of this invention. The principal part expanded sectional view which shows the structure of the vacuum circuit breaker which concerns on Example 2 of this invention. The principal part expanded sectional view which shows the structure of the vacuum circuit breaker which concerns on Example 3 of this invention. The principal part expanded sectional view which shows the structure of the vacuum circuit breaker which concerns on Example 4 of this invention. The side sectional view which looked at the composition of the vacuum circuit breaker from the side.

  Embodiments of the present invention are intended to alleviate the electric field of the main circuit conductor in contact with the insulation barrier. Embodiments of the present invention will be described below with reference to the drawings.

  First, a vacuum circuit breaker according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is an enlarged cross-sectional view of a main part showing the configuration of a vacuum circuit breaker according to Embodiment 1 of the present invention, and FIG. 2 is a diagram for explaining partial discharge characteristics of the vacuum circuit breaker according to Embodiment 1 of the present invention. . In FIG. 1, the same components as those in the prior art are denoted by the same reference numerals. Since the vacuum circuit breaker has the same configuration as the conventional method, the description thereof is omitted. Since the fixing method is the same for the upper main circuit conductor and the lower main circuit conductor, description will be made using the upper main circuit conductor side.

  As shown in FIG. 1, a plate-like upper main circuit conductor 20 is disposed on the lower surface of the upper flange portion 1a of the insulation barrier 1 molded with an insulating material such as an epoxy resin. Then, the bolt 4 is passed through from the upper surface of the upper flange portion 1a, and is fastened and fixed to the fixed side of the vacuum valve 5 having a pair of contactable and separable contacts. At both ends of the upper main circuit conductor 20 in contact with the upper flange portion 1a, chamfered portions 20a that are chamfered by several mm are provided. The upper flange 1a may be formed with a convex recess 1c.

  Next, partial discharge of the chamfered portion 20a will be described with reference to FIG.

  As shown in FIG. 2, when the upper main circuit conductor 20 is charged and reaches a critical electric field where partial discharge occurs, first, a minute partial discharge is generated from point A. This partial discharge spreads in an arc shape indicated by a dotted line centering on point A, and apparently exhibits a so-called corona stabilizing action that increases the curvature of the upper main circuit conductor 20. For this reason, electric field relaxation is achieved in the wedge-shaped space formed between the chamfered portion 20a and the upper flange portion 1a, and the occurrence of partial discharge is suppressed. Furthermore, generation | occurrence | production of the partial discharge in the convex-concave part 1c is suppressed. This partial discharge shows a large discharge that leads to dielectric breakdown, and suppresses this large discharge.

  Such a corona stabilizing action is easily exhibited in air insulation where the insulation distance between the upper main circuit conductor 20 and the operating mechanism at the ground potential is relatively large, and the critical electric field is lower than in vacuum. For example, when the insulation voltage of the rated voltage of 6 kV is increased to the rated voltage of 12 kV, the effect is greatly exerted. Moreover, by providing the chamfered portion 20a, the area where the convex and concave portions 1c are formed is reduced, and the probability of occurrence of partial discharge is reduced.

  According to the vacuum circuit breaker according to the first embodiment, since the chamfered portion 20a is provided at the end of the upper main circuit conductor 20 in contact with the upper flange portion 1a of the insulation barrier 1 so that the corona stabilizing action works, The partial discharge characteristic generated between the flange portion 1a and the upper main circuit conductor 20 can be improved.

  Next, a vacuum circuit breaker according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing the configuration of the vacuum circuit breaker according to the second embodiment of the present invention. The second embodiment differs from the first embodiment in the shape of the upper main circuit conductor. In FIG. 3, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, at both ends of the upper main circuit conductor 21, curved surface portions 21a having a diameter comparable to the plate thickness are provided. That is, a round edge conductor is used.

  As a result, the critical electric field at which the partial discharge is generated is higher than that in the first embodiment, and when a minute partial discharge is generated, a larger apparent electrode is formed, and the generation of a large partial discharge is suppressed. Further, even in the upper main circuit conductor 21 having the curved surface portion 21a, the area in contact with the upper flange portion 1a is reduced, and the occurrence probability of partial discharge is reduced.

  According to the vacuum circuit breaker according to the second embodiment, the partial discharge characteristics can be further improved as compared with the first embodiment.

  Next, a vacuum circuit breaker according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 4 is an enlarged cross-sectional view of a main part showing the configuration of the vacuum circuit breaker according to the third embodiment of the present invention. The third embodiment is different from the second embodiment in the shape of the upper main circuit conductor. In FIG. 4, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, a plurality of groove portions 21b are provided on the surface where the upper main circuit conductor 21 is in contact with the upper flange portion 1a. The groove 21b has a depth of about 1 mm and a width of several mm.

  According to the vacuum circuit breaker according to the third embodiment, in addition to the effects of the second embodiment, the area where the upper main circuit conductor 21 is in contact with the upper flange portion 1a can be further reduced.

  Next, a vacuum circuit breaker according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view of the main part showing the configuration of the vacuum circuit breaker according to the fourth embodiment of the present invention. The difference between the fourth embodiment and the third embodiment is that a conductive member is used. In FIG. 5, the same components as those in the third embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 5, an elastic member 22 such as a rubber sheet is provided at a portion where the upper flange portion 1a and the upper main circuit conductor 21 are in contact with each other. Furthermore, you may apply | coat a conductive paint to the upper flange part 1a surface. These prevent the formation of a gap having a potential difference.

  According to the vacuum circuit breaker according to the fourth embodiment, in addition to the effects of the third embodiment, the partial discharge characteristics between the upper main circuit conductor 21 and the upper flange portion 1a can be further improved.

DESCRIPTION OF SYMBOLS 1 Insulation barrier 1a Upper flange part 1b Lower flange part 1c Convex recessed part 2, 20, 21 Upper main circuit conductor 3 Lower main circuit conductor 4 Bolt 5 Vacuum valve 6 Moving side electricity supply shaft 7 Flexible conductor 8 Insulation operation rod 9 Operation lever 10 Operation mechanism 20a Chamfer 21a Curved surface 21b Groove 22 Elastic member

Claims (2)

A vacuum valve having a pair of detachable contacts;
A main circuit conductor connected to the main circuit of the vacuum valve;
A flange portion of an insulation barrier to which the main circuit conductor is fixed;
A vacuum circuit breaker having an operation mechanism for opening and closing the vacuum valve,
While providing a chamfered portion at the end portion of the main circuit conductor in contact with the flange portion ,
A vacuum circuit breaker characterized in that a plurality of grooves are provided in the main circuit conductor surface in contact with the flange portion . The vacuum circuit breaker according to claim 1, wherein an elastic member is provided between the flange portion and the main circuit conductor .

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