JP2013004767A - Stationary induction apparatus and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the voltage endurance and reduce the size of a stationary induction apparatus by restraining the junction parts between the insulation layers on a coil plate surface and spacers from becoming discharge starting points as a result of electric field concentration thereon.SOLUTION: Two coil plates 1a and 1b having a plurality of spacers 7 sandwiched therebetween are heated, and while dielectric layers 4a and 4b are being softened, the two coil plates 1a and 1b are pressurized in the vertical direction, whereby the insulation spacers 7 are joined to respective insulation layers 3a and 3b of the two coil plates 1a and 1b via the dielectric layers 4a and 4b. At this time, the dielectric layers 4a and 4b have curved surface portions 5a and 5b without corners formed thereon, with grooves 6a and 6b formed between the curved surface portions 5a and 5b and the insulation spacers 7. The grooves 6a and 6b help to reduce a local electric field in the junctions between the insulation spacers 7 and the insulation layers 3a and 3b, thereby making it possible to restrain the junctions from becoming discharge starting points.

Description

  The present invention relates to a static inductor and a method for manufacturing the same, and more particularly to an insulating structure of a coil group of an oil-filled transformer.

  Conventionally, in static inductors such as outer iron type transformers, inner iron type transformers, and reactors, a plurality of coil plates and spacing pieces (spacers) made of an insulating material are alternately arranged to form a coil group. Yes. Between the coil plates, an oil flow path as a cooling medium is formed. The coil plate is usually composed of a winding layer (coil layer) and insulating layers arranged on both sides thereof. When manufacturing a coil group, a plurality of spacers are arranged on an insulating layer of a coil plate, and an insulating layer of another coil plate is further arranged thereon to form an insulating structure.

  As a prior example of such an insulating structure, in Patent Document 1, as shown in FIG. 7, a U shape made of an insulating material such as a press board, a pulp mold, or paper is provided between a winding layer 41 and a spacing piece 43. A transformer is provided which is provided with a shin-like portion 44 and supports the eddy current generating piece 45 projecting into the cooling groove 46 by the shin-like portion 44.

  Further, in Patent Document 2, as shown in FIG. 8A, an insulating spacer 52 is attached to the outer periphery of the winding layer 51 via insulating paper 53 provided with a large number of circular holes 54, and an axial cooling duct is provided. A cylindrical winding structure is provided. In this example, by making the periphery of the hole 54 project like a projecting portion 55 shown in FIG. 8B, the turbulent flow of oil is promoted, and the efficiency from the winding layer 51 to the cooling duct 56 is improved. We are trying to dissipate heat.

JP 52-59812 A Japanese Utility Model Publication No. 61-75110

  In the conventional static inductor, the spacer used for the insulating structure is pasted on the insulating layer of the coil plate with an adhesive or the like. In such a structure, the electric field concentrates at the junction between the insulating layer and the spacer (forms a local high electric field portion) and becomes a discharge starting point. As a result, the high withstand voltage and miniaturization of the static inductor are hindered. It was a factor.

  In Patent Document 1 and Patent Document 2 described above, the local electric field generated at the junction between the insulating layer and the spacer is not described in particular. There are corners at the junctions, and it is considered that a local electric field is generated at these junctions.

  The present invention has been made to solve the above-described problems, and suppresses the electric field from concentrating on the junction between the insulating layer on the coil plate surface and the spacer to become a discharge starting point, thereby increasing the withstand voltage. It is another object of the present invention to provide a static inductor that can be reduced in size and a manufacturing method thereof.

A stationary inductor according to the present invention includes a coil group in which a coil plate having an insulating layer on both sides of a coil layer and a spacer made of an insulating material are alternately arranged, and has a cooling medium flow path between the coil plates. A static inductor, wherein the spacer is bonded to the insulating layer via a dielectric layer disposed on the insulating layer, and the dielectric layer has a thickness of the peripheral region of the junction with the spacer A curved surface portion that continuously decreases toward the joint portion is provided, and a groove having the joint portion as a bottom portion is provided between the curved surface portion and the spacer.

  The method for manufacturing a static inductor according to the present invention includes a coil group in which a coil plate having an insulating layer on both sides of a coil layer and a spacer made of an insulating material are alternately arranged, and a cooling medium between the coil plates. A dielectric layer forming step of disposing a dielectric layer made of a thermoplastic resin at a plurality of locations where spacers on the insulating layer of the coil plate are disposed, In addition, a spacer is disposed on each dielectric layer, and a dielectric layer disposed on an insulating layer of another coil plate is positioned on each of the plurality of spacers in correspondence with each other, and a plurality of coils are formed by two coil plates. A positioning step for sandwiching the spacers of the two, and heating the two coil plates following the positioning step to apply pressure to the two coil plates from above and below with the dielectric layer softened, respectively. A dielectric layer on the insulation layer A spacer bonding step for bonding the spacer, and in the spacer bonding step, the dielectric layer has a curved surface portion whose thickness decreases continuously from the peripheral region of the bonding portion with the spacer toward the bonding portion. By forming the groove, a groove having a joint portion as a bottom portion is formed between the curved surface portion and the spacer.

  According to the static inductor according to the present invention, the spacer is joined to the insulating layer of the coil plate via the dielectric layer, and the groove is provided between the curved surface portion of the dielectric layer and the spacer, whereby the spacer and the insulating layer are provided. Since the local electric field of the junction is relaxed and the junction can be prevented from becoming a starting point of discharge, it is possible to achieve high withstand voltage and downsizing.

  In addition, according to the method for manufacturing a static inductor according to the present invention, in the spacer bonding step, the two coil plates are heated to soften the dielectric layer, and pressure is applied to the two coil plates from above and below. As a result, a curved surface portion and a groove are formed in the dielectric layer, so there is no need to perform a separate process for forming the curved surface portion and the groove, and a static voltage capable of achieving high withstand voltage and miniaturization can be achieved. An inductor can be manufactured easily.

It is a perspective view which shows the external iron type transformer which concerns on Embodiment 1 of this invention. It is a figure explaining the coil which concerns on Embodiment 1 of this invention. It is a figure explaining the coil board which concerns on Embodiment 1 of this invention. It is a partial expanded sectional view of the coil which concerns on Embodiment 1 of this invention. It is a figure which shows the relationship between the shape of the groove | channel formed in the dielectric material layer of the coil which concerns on Embodiment 1 of this invention, and an electric field relaxation rate. It is a partial expanded sectional view of the coil which concerns on Embodiment 2 of this invention. It is a figure which shows the insulation structure of the cylindrical winding of the conventional transformer. It is a figure which shows the insulation structure of the cylindrical winding of the conventional transformer.

Embodiment 1 FIG.
Hereinafter, a stationary inductor and a manufacturing method thereof according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a partial cross section of a shell-type transformer that is a stationary inductor according to the first embodiment, and FIG. 2 is a diagram for explaining a coil of the shell-type transformer. The outer iron type transformer 100 has a configuration in which a coil 10 in which a plurality of coil plates are laminated and an iron core 20 made of a material having a high saturation magnetic flux density and high permeability (for example, a silicon steel plate) is surrounded by a tank wall 30. Yes.

As shown in FIG. 2A, the coil 10 includes a coil plate 1 having insulating layers on both sides of the coil layer.
a, 1b, 1c, 1d... and spacers made of an insulating material (hereinafter referred to as insulating spacers) are alternately arranged to form a coil group shown in FIG. The coil 10 shown in FIG. 1 shows a cross section obtained by cutting the coil group shown in FIG. 2B at a portion indicated by A in the drawing. Between the plurality of coil plates 1, there is an oil passage such as silicone oil or mineral oil which is an insulator and a cooling medium.

  The arrangement of the insulating spacer with respect to the coil plate 1 is determined in consideration of the efficiency of coil cooling by oil and whether the structure can withstand short-circuit electromagnetic force. In the first embodiment, as shown in FIG. 3, a plurality of insulating spacers 7 are joined on the insulating layer 3 arranged on the surface of the coil plate 1 via a dielectric layer (not shown). Note that the shape, size, number, arrangement, and the like of the insulating spacer 7 shown in FIG. 3 are not limited to this.

  A structure in the vicinity of the joint between coil plate 1 and insulating spacer 7 in shell-type transformer 100 according to the first embodiment will be described with reference to FIG. In FIG. 4, the lower coil plate 1a includes a coil layer 2a, an insulating layer 3a made of an insulating plate, and a thermoplastic resin (for example, polypropylene) disposed at a location where an insulating spacer 7 on the insulating layer 3a is disposed. It is comprised including the dielectric material layer 4a which consists of. Although not shown, an insulating layer is also disposed on the opposite surface (lower side in FIG. 4) of the coil layer 2a.

  Similarly, the upper coil plate 1b is a dielectric made of a thermoplastic resin (eg, polypropylene) disposed at a location where the coil layer 2b, an insulating layer 3b made of an insulating plate, and an insulating spacer 7 on the insulating layer 3b are provided. The body layer 4b is included. Although not shown, an insulating layer is also disposed on the surface opposite to the coil layer 2b (upper side in FIG. 4). An insulating spacer 7 is bonded to the insulating layers 3a and 3b of the coil plates 1a and 1b via dielectric layers 4a and 4b. The insulating spacer 7 keeps the interval between the coil plates 1a and 1b constant and forms a flow path for oil as a cooling medium.

  The dielectric layers 4a and 4b have curved surface portions 5a and 5b whose thickness decreases continuously from the peripheral region of the joint portion with the insulating spacer 7 toward the joint portion, and the curved surface portions 5a and 5b. And the insulating spacer 7 are provided with grooves 6a and 6b whose bottoms are the joints (portions indicated by A and B in FIG. 4). In other words, a recess is formed in the center of the dielectric layers 4a and 4b, the curved surface portions 5a and 5b are side surfaces of the recess, and the insulating spacer 7 is bonded to the inside of the recess.

  The curved surface portions 5a and 5b are formed of curves in which the cross-sectional shape in the direction perpendicular to the surfaces of the insulating layers 3a and 3b does not have corner portions. By adopting a shape having no corners, the local electric field at the junction with the insulating spacer 7 is relaxed, and the junction is prevented from becoming a discharge starting point. Thus, in the outer iron type transformer 100 in which the grooves 6a and 6b are provided at the joint portion with the spacer 7, the local electric field at the joint portion is reduced by 10 to 20% as compared with the case where the groove is not provided. Can do.

  Also, as shown in FIG. 4, the groove 6a has a depth dimension of a distance s1 from the surface of the dielectric layer 4a to the bottom (junction), and the width dimension of the groove width perpendicular to the depth direction is the dielectric. When the distance s2 from the position where the thickness of the layer 4a starts to decrease to the insulating spacer 7 is set, the depth dimension and the width dimension are substantially equal. Furthermore, the sum of the depth dimension and the width dimension is 0.6 mm or more, preferably 1 mm or more (the same applies to the groove 6b).

The relationship between the shape (size) of the grooves 6a and 6b and the electric field relaxation rate will be described with reference to FIG. In FIG. 5, the horizontal axis represents the sum of the depth dimensions and width dimensions (s1 and s2) of the grooves 6a and 6b, and the vertical axis represents the electric field relaxation rate (%). As shown in FIG. 5, in order to reduce the local electric field at the junction, which is likely to be the starting point of discharge, the sum of the width dimension and the depth dimension is desirably 0.6 mm or more. In the first embodiment, 1 mm or more is used. It was. That is, both s1 and s2 are 0.3 mm
It is necessary to form the above grooves. When polypropylene (molded product) is used as the dielectric layers 4a and 4b, a groove having a thickness of about 1 mm or more is usually used because of material strength and ease of handling. It is easy to form 6a and 6b.

  Next, a method for manufacturing the coil 10 of the outer iron type transformer 100 according to the first embodiment will be described with reference to FIG. First, the dielectric layers 4a made of thermoplastic resin are disposed at a plurality of locations where the insulating spacers 7 are disposed on the insulating layer 3a of the lower coil plate 1a (dielectric layer forming step). Here, an example in which polypropylene having a melting point of 165 ° C. is used as the thermoplastic resin will be described.

  Subsequently, an insulating spacer 7 is disposed at the center of each dielectric layer 4a, and a dielectric layer 4b disposed on the insulating layer 3b of another coil plate 1b is arranged on the plurality of spacers 7. Then, the plurality of spacers 7 are sandwiched between the two coil plates 1a and 1b (positioning step).

  Following the positioning step, the two coil plates 1a and 1b are heated, and the dielectric layers 4a and 4b are softened, and pressure is applied to the two coil plates 1a and 1b from above and below to form the two coils. An insulating spacer 7 is bonded to the insulating layers 3a and 3b of the plates 1a and 1b via the dielectric layers 4a and 4b (spacer bonding step).

  The spacer bonding process also serves as a dielectric layer forming process. By applying pressure to the two coil plates 1a and 1b in a state where the dielectric layers 4a and 4b are softened, the dielectric layers 4a and 4b are bonded. Are formed with curved surface portions 5a and 5b whose thickness decreases continuously from the peripheral region of the joint portion with the insulating spacer 7 toward the joint portion. Between these, grooves 6a and 6b with the joint portion as the bottom are formed. The pressure applied to the two coil plates 1a and 1b is such that the depth dimension (s1) and the width dimension (s2) of the grooves 6a and 6b are substantially equal, and the sum of the depth dimension and the width dimension is 0.6 mm or more. To be determined.

  In the spacer bonding step, the temperature at which the two coil plates 1a and 1b are heated is equal to or higher than the temperature at which the thermoplastic resin softens and is lower than the melting point of the thermoplastic resin. When polypropylene having a melting point of 165 ° C. is used, heating is performed so that the temperature of the polypropylene is increased to about 150 ° C. In addition, since the maximum temperature of the oil at the time of operation of the outer iron type transformer 100 is around 110 ° C. and is usually about 50 ° C. to 70 ° C., the hardness of the polypropylene (dielectric layers 4a and 4b) changes during operation. Does not occur, and there is no problem in terms of strength.

  In the first embodiment, the case where polypropylene is used as the dielectric layers 4a and 4b has been described as an example. However, any thermoplastic resin that is softened at a temperature higher than the maximum oil temperature during operation described above may be used. The dielectric layers 4a and 4b can be used.

  As described above, according to the first embodiment, the insulating spacer 7 is joined to the insulating layers 3a and 3b of the coil plates 1a and 1b via the dielectric layers 4a and 4b, and the curved surfaces of the dielectric layers 4a and 4b are obtained. By providing the grooves 6a and 6b between the portions 5a and 5b and the insulating spacer 7, the local electric field at the junction between the insulating spacer 7 and the insulating layers 3a and 3b is relaxed, and the junction is prevented from becoming a discharge starting point. can do. As a result, it is possible to increase the withstand voltage and the size of the outer iron type transformer 100.

Further, according to the manufacturing method in the first embodiment, in the spacer bonding step, the two coil plates 1a and 1b are heated and the dielectric layers 4a and 4b are softened, and the two coil plates 1a and 1b are softened. Since the grooves 6a and 6b are formed by applying pressure from above and below to 1b, the groove 6
It is not necessary to separately perform a process for forming a and 6b, and the outer iron type transformer 100 capable of achieving high withstand voltage and downsizing can be easily manufactured.

  Furthermore, the curved surface portions 5a and 5b (grooves 6a and 6b) formed by the manufacturing method according to the first embodiment have a shape that does not have corner portions, so that they are compared with intentionally excavated grooves and notches. The effect of suppressing the occurrence of discharge is high.

Embodiment 2. FIG.
Since the configuration of the outer iron type transformer and the coil group according to the second embodiment of the present invention is the same as that of the first embodiment, the description thereof is omitted. The structure in the vicinity of the joint between the coil plate and the insulating spacer in the outer iron type transformer according to the second embodiment will be described with reference to FIG.

  In FIG. 6, a lower coil plate 1c is a dielectric made of a coil layer 2c, an insulating layer 3c made of an insulating plate, and a thermoplastic resin (for example, polypropylene) disposed in a fitting portion 8c formed in the insulating layer 3c. It is configured including the layer 4c. Although not shown, an insulating layer is also disposed on the opposite surface (lower side in FIG. 6) of the coil layer 2c.

  Similarly, the upper coil plate 1d has a coil layer 2d, an insulating layer 3d made of an insulating plate, and a dielectric layer 4d made of a thermoplastic resin (for example, polypropylene) disposed in a fitting portion 8d formed in the insulating layer 3d. It is comprised including. Although not shown, an insulating layer is also disposed on the opposite surface (upper side in FIG. 6) of the coil layer 2d. An insulating spacer 7 is joined to the insulating layers 3c and 3d of the coil plates 1c and 1d through dielectric layers 4c and 4d.

  As shown in FIG. 6, the fitting portions 8c and 8d provided in the insulating layers 3c and 3d have a depth substantially equal to the thickness of the peripheral region of the dielectric layers 4c and 4d. In the second embodiment, the dielectric layers 4c and 4d are disposed in the fitting portions 8c and 8d so that the dielectric layers 4c and 4d do not protrude from the surfaces of the insulating layers 3c and 3d. .

  In the manufacturing method of the coil of the outer iron type transformer in the second embodiment, the depth of the insulating layers 3c and 3d is substantially equal to the thickness of the peripheral region of the dielectric layers 4c and 4d before the dielectric layer forming step. The step of forming the fitting portions 8c and 8d having is performed. Thereafter, in the dielectric layer forming step, the dielectric layer 4a made of a thermoplastic resin is disposed in the fitting portions 8c and 8d provided in the insulating layers 3c and 3d of the coil plates 1c and 1d. Since the subsequent steps are the same as those in the first embodiment, description thereof is omitted.

  According to the second embodiment, the same effects as those of the first embodiment can be obtained, and the dielectric layers 4c and 4d are disposed in the fitting portions 8c and 8d provided in the insulating layers 3c and 3d. Since the body layers 4c and 4d do not protrude from the surfaces of the insulating layers 3c and 3d, the turbulence of the oil flow by the dielectric layers 4c and 4d is suppressed, and the influence of charging on the surfaces of the insulating layers 3c and 3 can be reduced. A more reliable outer iron type transformer can be obtained.

  In the first and second embodiments, the outer iron type transformer has been described as an example. However, other stationary inductors having a cooling medium flow path between the coil plates, for example, the inner iron type The present invention can also be applied to a transformer, a reactor, and the like.

  INDUSTRIAL APPLICABILITY The present invention can be used as a stationary inductor having a cooling medium flow path between coil plates and a manufacturing method thereof.

1, 1a, 1b, 1c, 1d coil plate, 2a, 2b, 2c, 2d coil layer,
3, 3a, 3b, 3c, 3d Insulating layer (insulating plate), 4a, 4b, 4c, 4d Dielectric layer, 5a, 5b, 5c, 5d Curved surface, 6a, 6b, 6c, 6d Groove, 7 Insulating spacer,
8c, 8d fitting part, 10 coil, 20 iron core, 30 tank wall,
41, 42 Winding layer, 43 spacing piece, 44 U-shaped shin-like part, 45 eddy current generating piece,
46 cooling groove, 51 winding layer, 52 insulating spacer, 53 insulating paper, 54 holes,
55 Projection around hole, 56 cooling duct, 100 outer iron type transformer.

Claims (9)

  A stationary inductor having a coil group in which a coil plate having an insulating layer on both sides of a coil layer and a spacer made of an insulating material are alternately arranged, and having a cooling medium flow path between the coil plates, The spacer is bonded to the insulating layer via a dielectric layer disposed on the insulating layer, and the dielectric layer has a thickness of the layer from the peripheral region of the junction with the spacer. A stationary inductor having a curved surface portion that continuously decreases toward the portion, and a groove having the joint portion as a bottom portion is provided between the curved surface portion and the spacer.   The insulating layer further includes a fitting portion having a depth substantially equal to the thickness of the peripheral region of the dielectric layer, and the dielectric layer is disposed in the fitting portion so that the dielectric layer is the insulating layer. The stationary inductor according to claim 1, wherein the stationary inductor does not protrude from the surface.   3. The static inductor according to claim 1, wherein the curved surface portion of the dielectric layer is formed of a curve having a corner portion having a cross section perpendicular to the surface of the insulating layer.   The depth dimension of the groove is the distance from the surface of the dielectric layer to the bottom, and the width dimension of the groove width perpendicular to the depth direction is from the position where the thickness of the dielectric layer starts to decrease to the spacer. 3. The stationary inductor according to claim 1, wherein the depth dimension is substantially equal to the width dimension when the distance is set.   The static induction device according to claim 4, wherein the sum of the depth dimension and the width dimension is 0.6 mm or more. A method of manufacturing a static inductor having a coil group in which a coil plate having an insulating layer on both sides of a coil layer and a spacer made of an insulating material are alternately arranged and having a cooling medium flow path between the coil plates. And
A dielectric layer forming step of disposing a dielectric layer made of a thermoplastic resin at a plurality of locations where the spacer is disposed on the insulating layer of the coil plate;
The spacers are disposed on each of the dielectric layers, and the dielectric layers disposed on the insulating layer of another coil plate are positioned on the plurality of spacers in correspondence with each other, and the two sheets Positioning step of sandwiching the plurality of spacers with the coil plate of
Subsequent to the positioning step, the two coil plates are heated, and the dielectric layer is softened so that pressure is applied to the two coil plates from above and below, and the insulation of each of the two coil plates is applied. A spacer bonding step of bonding the spacer to the layer via the dielectric layer;
In the spacer bonding step, the curved surface portion is formed in the dielectric layer by forming a curved surface portion in which the thickness of the layer continuously decreases from the peripheral region of the bonding portion with the spacer toward the bonding portion. Forming a groove having the joint as a bottom between the spacer and the spacer.   Before the dielectric layer forming step, further comprising a step of forming a fitting portion having a depth substantially equal to the thickness of the peripheral region of the dielectric layer in the insulating layer, and in the dielectric layer forming step, The method for manufacturing a static inductor according to claim 6, wherein a dielectric layer is disposed in the fitting portion.   The temperature at which the two coil plates are heated in the spacer bonding step is equal to or higher than a temperature at which the thermoplastic resin is softened and is lower than a melting point of the thermoplastic resin. 6. A method of manufacturing a static inductor according to 6. In the spacer bonding step, the depth dimension of the groove is the distance from the surface of the dielectric layer to the bottom, and the width dimension of the groove width perpendicular to the depth direction starts to decrease the thickness of the dielectric layer. When the distance from the position to the spacer is set, the two coil plates are such that the depth dimension and the width dimension are substantially equal and the sum of the depth dimension and the width dimension is 0.6 mm or more. The method for manufacturing a static inductor according to claim 6, wherein the pressure applied to the coil is determined.

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