Tap changeover stand

Abstract

To provide a tap changeover stand having high electrical insulation properties.SOLUTION: A tap changeover stand base 1 used in a transformer, includes: a stand portion 2 having a plurality of tap terminals 3; and an insulating fixing leg portion 4 having one end portion provided on the stand portion 2 and the other end fixed to an earth terminal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tap-changing base. [Background technology]

[0002] Conventionally, an insulating tap changer has been used to change taps in a transformer (see Patent Documents 1 and 2). Such an insulating tap changer is attached to an earth terminal provided on a core fastening fixture for fixing a wound core having a coil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-112060 [Patent Document 2] Japanese Patent Application Publication No. 6-112061 Summary of the Invention [Problem to be solved by the invention]

[0004] Since the tap changer has a tap terminal, electrical insulation between the tap terminal and the earth terminal must be ensured. However, Patent Documents 1 and 2 do not fully consider the electrical insulation between the tap terminal and the earth terminal.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a tap changer base with high electrical insulation. [Means for solving the problem]

[0006] The tap changer of the present invention is a tap changer used in a transformer, and comprises a base portion having a plurality of tap terminals, and an insulating fixing leg portion having one end provided on the base portion and the other end fixed to an earth terminal. [Effects of the Invention]

[0007] According to the present invention, a tap changer base having high electrical insulation properties can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a tap changer base according to a first embodiment. [Figure 2] 1A and 1B are a front view and a bottom view of a tap changer base according to a first embodiment. [Figure 3] FIG. 10 is a perspective view of a tap changer base according to a second embodiment. [Figure 4] 10A and 10B are a front view and a bottom view of a tap changer base according to a second embodiment. [Figure 5] FIG. 4C is an enlarged cross-sectional view of the dashed oval portion of FIG. 4B. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will now be described with reference to the drawings showing embodiments thereof.

[0010] (Embodiment 1) Fig. 1 is a perspective view of a tap changer 1 according to embodiment 1, and Fig. 2 is a front view and a bottom view of the tap changer 1 according to embodiment 1. Fig. 2A is a front view of the tap changer 1, and Fig. 2B is a bottom view. For ease of explanation, embodiment 1 will be described taking a single-phase tap changer 1 as an example.

[0011] The tap changer 1 is used in an oil-filled transformer. The tap changer 1 is installed in a container (tank) containing insulating oil. The tap changer 1 includes a base 2, a plurality of tap terminals 3, and a mounting portion 4 (fixed leg portion). The tap changer 1 of this embodiment changes taps under no-load, no-voltage conditions.

[0012] The base 2 is made of a thermoplastic resin. The thermoplastic resin has heat resistance, oil resistance, and electrical insulation properties. Examples of the thermoplastic resin include polyamide resin and PPS (polyphenylene sulfide) resin. The thermoplastic resin may also be, for example, a thermoplastic engineering plastic (engineering plastic) or super engineering plastic, and may contain a reinforcing agent such as glass fiber or an inorganic filler.

[0013] The base 2 is plate-shaped. Specifically, the base 2 includes two rectangular portions of different lengths, which are arranged in the same plane and connected at their middle portions. Reinforcing ribs 21 are provided along the edges of the base 2. The reinforcing ribs 21 protrude in the thickness direction of the base 2.

[0014] The shorter of the two rectangular sections of the base section 2 is provided with an attachment section 4. The attachment sections 4 are connected to both ends of the shorter rectangular section. Each attachment section 4 has the same shape and is used to secure the tap changer base 1 (base section 2) to, for example, an earth terminal (not shown) of a core clamping fixture for securing a wound core.

[0015] The tap terminal 3 is made of, for example, brass and is a so-called insert metal fitting. The base 2 is provided with a plurality of bosses 22 that penetrate the base 2 in the thickness direction. Each boss 22 is cylindrical, with both ends of the boss 22 protruding from the corresponding two main surfaces of the base 2, and a tap terminal 3 is provided on each boss 22. Each tap terminal 3 is a terminal used to connect a tap wire drawn from a tap of a transformer or the like, or to fix a connection piece that electrically connects multiple tap wires.

[0016] The tap terminal 3 has a male thread portion 31, a female thread portion 32, and a cap nut 33. More specifically, the cap nut 33, which has a cylindrical shape with a bottom, is fitted into the boss 22, and the female thread portion 32 is formed on the cap nut 33. Therefore, the male thread portion 31 of the tap terminal 3 protrudes from one main surface of the base portion 2, and the female thread portion 32 opens from the other main surface opposite to the one main surface. In other words, the tap terminal 3 penetrates the base portion 2 in the thickness direction.

[0017] Each mounting portion 4 is substantially rectangular, extends away from the other main surface of the base portion 2, and separates from each other, with its ends bent parallel to the base portion 2. That is, the mounting portion 4 has an inclined portion 41 that extends outward from the base portion 2 at an angle relative to the thickness direction of the base portion 2, and a parallel portion 42 that is parallel to the base portion 2. One end of the inclined portion 41 is connected to the end of the shorter strip-shaped portion of the base portion 2, and the parallel portion 42 is connected to the other end of the inclined portion 41.

[0018] The mounting portion 4 is made of a thermoplastic resin that has heat resistance, oil resistance, and electrical insulation properties. That is, like the base portion 2, the mounting portion 4 is made of a thermoplastic resin such as polyamide resin, PPS (polyphenylene sulfide) resin, etc.

[0019] Reinforcing ribs 44 are provided along the edges of the mounting portion 4. The reinforcing ribs 44 protrude in the thickness direction of the mounting portion 4 and are connected to the reinforcing ribs 21 of the base portion 2. A boss 43 is provided in the center of the parallel portion 42 and is used to attach the tap changer 1 to the earth terminal of the core tightening bracket. The tap changer 1 is fixed by inserting a bolt (not shown) into the boss 43 and screwing it to the earth terminal.

[0020] In the tap changer 1 according to the first embodiment, the base portion 2 and the mounting portion 4 are integrally molded. Both the base portion 2 and the mounting portion 4 are made of thermoplastic resin, and are manufactured by, for example, injection molding the thermoplastic resin.

[0021] As described above, in the tap changer 1 of embodiment 1, the mounting portion 4 is made of a thermoplastic resin with excellent insulating properties, thereby improving the electrical insulation between the earth terminal of the core tightening bracket and the tap terminal 3.

[0022] Furthermore, in the tap changer base 1 of embodiment 1, the mounting portion 4 (inclined portion 41) is arranged at an angle to the base portion 2, so that the creepage distance between the earth terminal and the tap terminal 3 can be extended compared to when it is arranged vertically, thereby further improving electrical insulation.

[0023] In the tap changer 1 according to the first embodiment, the base 2 and the mounting portion 4 are integrally molded as described above. Therefore, the base 2 and the mounting portion 4, i.e., the tap changer 1, can be manufactured by, for example, injection molding, which not only significantly reduces costs but also increases design freedom. Furthermore, the number of steps required for assembling the tap changer 1 can be reduced, and the tap changer 1 can be made more compact.

[0024] Furthermore, in the tap changer base 1 according to the first embodiment, as described above, the reinforcing rib 44 of the mounting portion 4 is connected to the reinforcing rib 21 of the base portion 2. This allows the strength of the tap changer base 1 to be increased.

[0025] In addition, although the above description has been given taking as an example a case where the base portion 2 and the mounting portion 4 are integrally molded, the present invention is not limited to this. It goes without saying that the effects of the present invention can be achieved even in a configuration where the base portion 2 and the mounting portion 4 are separate members and the mounting portion 4 is attached to the base portion 2 by means of screws or the like.

[0026] (Embodiment 2) Fig. 3 is a perspective view of a tap changer 1A according to embodiment 2, and Fig. 4 is a front view and a bottom view of the tap changer 1A according to embodiment 2. Fig. 4A is a front view of the tap changer 1A, and Fig. 4B is a bottom view. In embodiment 2, a three-phase tap changer 1A will be described.

[0027] As in the first embodiment, the tap changer base 1A is used in an oil-immersed transformer and includes a base portion 2A, a plurality of tap terminals 3A, and a mounting portion 4A (fixing leg portion). Figures 3 and 4 show a case in which a pair of tap terminals 3A are connected by a connecting piece P. The connecting piece P is fixed to the pair of tap terminals 3A by a nut.

[0028] The base portion 2A is plate-shaped and made of a thermoplastic resin such as polyamide resin or PPS resin. Specifically, the base portion 2A has a semicircular portion and a semi-elliptical portion with a smaller diameter than the semicircular portion, and the semicircular portion and the semi-elliptical portion are arranged on the same plane. The semi-elliptical portion is connected to the center of the linear edge of the semicircular portion. The base portion 2A has reinforcing ribs 21A along its edges. The reinforcing ribs 21A protrude in the thickness direction of the base portion 2A.

[0029] Mounting portions 4A are provided on the semicircular portion of base portion 2A. Mounting portions 4A are connected to both ends of the linear edges of the semicircular portion. Each mounting portion 4A has the same shape and is used to secure the tap changer base 1A (base portion 2A) to the earth terminal (not shown) of the core clamping fixture that secures the wound core.

[0030] The tap terminal 3A is made of, for example, brass and is a so-called insert metal fitting. A plurality of bosses 22A are protruding from the semicircular and semi-elliptical portions of the base portion 2A, penetrating the base portion 2A in the thickness direction, and a tap terminal 3A is provided on each boss 22A. The tap terminal 3A has a male thread portion 31A, a female thread portion 32A, and a cap nut 33A. The tap terminal 3A and the boss 22A are the same as the tap terminal 3 and the boss 22 of the first embodiment, and detailed description thereof will be omitted.

[0031] The mounting portion 4A is substantially rectangular and extends away from the base portion 2A, with its end bent parallel to the base portion 2A. That is, the mounting portion 4A has a vertical portion 41A that extends along the thickness direction of the base portion 2A, i.e., perpendicular to the main surface of the base portion 2A, and a parallel portion 42A that is parallel to the base portion 2A. One end of the vertical portion 41A is connected to the base portion 2A, and the parallel portion 42A is connected to the other end of the vertical portion 41A. The convex corner at the tip of the parallel portion 42A is rounded and chamfered.

[0032] The mounting portion 4A is made of a thermoplastic resin that has heat resistance, oil resistance, and electrical insulation properties, such as a polyamide resin, PPS resin, or the like, similar to the base portion 2A.

[0033] A reinforcing rib 44A is provided along the edge of the mounting portion 4A. The reinforcing rib 44A protrudes in the thickness direction of the mounting portion 4A and is connected to the reinforcing rib 21A of the base portion 2A. A boss 43A is provided in the center of the parallel portion 42A and is used to attach the tap changer base 1A to the earth terminal of the core tightening bracket. The tap changer base 1A is fixed by inserting a bolt (not shown) into the boss 43A and screwing it to the earth terminal.

[0034] In addition, in the tap changer base 1A according to the second embodiment, the attachment portion 4A is provided with an uneven portion 411. Fig. 5 is an enlarged cross-sectional view of the portion indicated by the broken line in Fig. 4B. The uneven portion 411 is formed on the vertical portion 41A and extends in a direction intersecting the longitudinal direction of the mounting portion 4A (vertical portion 41A). In the uneven portion 411, the distance between adjacent convex portions (W in FIG. 5) is 1 mm or more. The distance W between adjacent convex portions of the uneven portion 411 is, for example, 1 mm to 2 mm.

[0035] In the tap changer base 1A according to the second embodiment, the base portion 2A and the attachment portion 4A are integrally molded. Both the base portion 2A and the attachment portion 4A are made of thermoplastic resin and are manufactured by, for example, injection molding.

[0036] As described above, in the tap changer 1A of embodiment 2, the mounting portion 4A is made of a thermoplastic resin with excellent insulating properties, thereby improving the electrical insulation between the earth terminal of the core fastening fixture and the tap terminal 3A.

[0037] In the tap changer 1A according to the second embodiment, the base portion 2A and the mounting portion 4A are integrally molded as described above. Therefore, the tap changer 1 can be manufactured by, for example, injection molding, which significantly reduces costs and increases design flexibility. Furthermore, the number of steps required for assembling the tap changer 1A can be reduced, and the tap changer 1A can be made more compact.

[0038] Furthermore, in the tap changer base 1A according to the second embodiment, as described above, the mounting portion 4A (vertical portion 41A) is formed with the uneven portion 411, and the spacing W between the adjacent protrusions in the uneven portion 411 is 1 mm or more. This allows the creepage distance between the earth terminal and the tap terminal 3A to be increased, further improving the electrical insulation.

[0039] In the above, the case where the base portion 2A and the mounting portion 4A are integrally molded is taken as an example. However, the present invention is not limited to this. It goes without saying that the effects of the present invention can be achieved even in a configuration in which the base portion 2A and the mounting portion 4A are separate members and the mounting portion 4A is attached to the base portion 2A by means of screws or the like.

[0040] In the above description, the mounting portion 4A (vertical portion 41A) is provided perpendicular to the base portion 2A, but the present invention is not limited to this, and the mounting portion 4A may be provided at an angle to the base portion 2A, as in embodiment 1. In this case, the creepage distance between the earth terminal and the tap terminal 3A is extended, thereby improving electrical insulation.

[0041] The same parts as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

[0042] The technical features (constituent elements) described in the first and second embodiments can be combined with each other, and by combining them, new technical features can be achieved. The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims.

[0043] The matters described in each embodiment can be combined with each other. Furthermore, the independent claims and dependent claims described in the claims can be combined with each other in any and all combinations, regardless of the reference format. Furthermore, the claims use a format in which a claim references two or more other claims (multiple claim format), but this is not limited to this. A multiple claim (multi-multi claim) that references at least one other multiple claim may also be used. [Explanation of symbols]

[0044] 1,1A: Tap changer base, 2,2A: Base, 3,3A: Tap terminal, 4,4A: Mounting part (fixed leg), 411: Concave / convex part

Claims

1. A tap changer for use in a transformer, comprising: a base having a plurality of tap terminals; an insulating fixing leg portion, one end of which is provided on the base portion and the other end of which is fixed to a ground terminal; A tap changer comprising:

2. The base portion has a plate shape, 2. The tap changer base according to claim 1, wherein the fixing leg extends obliquely relative to the base portion.

3. The tap changer according to claim 1 , further comprising a concave-convex portion provided on the fixed leg portion and extending in a direction intersecting with the longitudinal direction of the fixed leg portion.

4. 2. The tap changer according to claim 1, wherein the fixed leg is made of a thermoplastic resin.

5. the base is made of a thermoplastic resin; The tap changer base according to any one of claims 1 to 4, wherein the base portion and the fixing leg portion are integrally formed.

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