JP2010251543A - Resin molded coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulated molded coil capable of suppressing the generation of partial discharge and capable of being easily applied to static induction equipment of special high-voltage class. <P>SOLUTION: In a resin molded coil, a plurality of unit coils 2 formed in an annular shape by winding magnet wires 5 are arrayed and connected in series in the axial direction, and a plurality of electrostatic shielding layers 6 having high resistance values are mounted so as to discretely surround a plurality of these unit coils 2. In the resin molded coil, a resin molded layer 4 molding a plurality of these whole electrostatic shielding layer 6 is mounted, and a conductor at a winding-start end 5a positioned inside the unit coils 2 and a conductor at a winding-end end 5b positioned outside the unit coils 2 are connected electrically to the inner peripheries 6A and outer peripheries 6B of the electrostatic shielding layers 6 surrounding the unit coils 2 respectively (connection points 8A and 8B). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin molded coil used for static induction equipment such as a transformer and a reactor.

  As coils used in static induction devices such as transformers and reactors, resin-molded coils having a structure in which the periphery of the coil is molded with an insulating resin are widely used. In this resin mold coil, first, a unit coil in which magnet wires are wound in an annular shape is manufactured, and then a plurality of them are stacked in the axial direction and fixed in a mold, and finally the whole is made of a thermosetting resin. Produced by molding. The method for connecting a plurality of unit coils varies depending on the application, but is generally connected in series for high-voltage equipment.

  In the case of this type of resin mold coil, it is difficult to make the unit coil formed by winding the magnet wire in an annular shape and the mold layer sufficiently close to each other, and a minute gap remains at the interface between them. There is. Moreover, since the unit coil is formed by closely winding the magnet wire, the resin hardly enters the narrow gap between the magnet wires, and a minute gap may remain inside the unit coil. In this resin-molded coil, a voltage is applied between the magnet wires, and a voltage is also applied between the ground (earth) and the magnet wire. When the applied voltage increases, a small gap is present. Since discharge occurs, the voltage applied between the magnet wires is suppressed, and the distance to ground, which is the physical insulation distance between the mold layer and the structure (referred to as an iron core of a mold transformer having a ground potential), is reduced. Measures such as taking large were necessary.

  As a conventional technique for solving such a problem, for example, Patent Document 1 discloses a technique for reducing the viscosity of an injected resin to prevent voids from remaining in the resin. Patent Document 2 discloses a technique for improving crack resistance and partial discharge resistance by providing a surface conductive layer made of a conductive polymer on the surface of a resin mold layer. Further, in Patent Document 3, when the lightning impulse enters the transformer, the highest voltage is applied to the unit coil close to the power supply terminal. Therefore, the thickness of the insulating portion covering the inner peripheral side of the unit coil close to the power supply terminal is disclosed. Is disclosed to be thicker than a portion covering the inner peripheral side of another unit coil.

Japanese Patent Laid-Open No. 08-316055 JP 08-264347 A Japanese Patent Application Laid-Open No. 07-122439

  As a power transformer, a 1000 kVA class transformer is used, but as a resin mold coil used in such a special high voltage class transformer, the above-mentioned countermeasures are not sufficient, and partial discharge is not possible. There is a need for further techniques to prevent the occurrence.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an insulated mold coil that can suppress the occurrence of partial discharge and can be easily applied to a special high-voltage class static induction device. It is in.

  The resin-molded coil of the present invention is provided such that a plurality of unit coils formed by winding a magnet wire in an annular shape are arranged in series in an axial direction and are connected in series to individually surround the plurality of unit coils. A plurality of electrostatic shield layers having a high resistance value, and a resin mold layer for molding all of the plurality of electrostatic shield layers, and a conductor of a magnet wire located inside the unit coil, and The conductor of the magnet wire located outside is electrically connected to the inner periphery and the outer periphery of the electrostatic shield layer surrounding the unit coil.

  According to such a configuration, since the electrostatic shield layer is provided around the unit coil, the potential of the electrostatic shield layer becomes an intermediate potential generated in the internal unit coil, and the electrostatic seal layer The electric field inside becomes smaller. Therefore, even if minute gaps remain on the outer peripheral surface and inner peripheral surface of the unit coil, or even if minute gaps remain inside the unit coil, the electric field in all the gaps is reduced, so the voltage is increased. However, partial discharge can be suppressed from occurring inside the electrostatic shield layer. In addition, since the conductor of the magnet wire located inside the unit coil and the conductor of the magnet wire located outside are electrically connected to the inner peripheral portion and the outer peripheral portion of the electrostatic shield layer surrounding the unit coil, The potential of the electric shield layer can be fixed, and the insulation distance between the electrostatic shield layer and the unit coil can be set small. Moreover, there is no minute gap between the mold layer outside the electrostatic shield layer and there is no need to worry about the occurrence of partial discharge outside the electrostatic shield layer, thus extending the physical insulation distance. The electric field between the electrostatic shield layer and the ground can be set large without any problem. And since an electrostatic shield layer has a high resistance value, the eddy current which generate | occur | produces when a magnetic flux links can be suppressed, and the loss which generate | occur | produces in an electrostatic shield layer can be suppressed. In other words, even if the voltage is increased, the occurrence of partial discharge can be suppressed while remaining compact, so that it can be easily applied to a special high voltage class static induction device.

  The insulated molded coil of the present invention can suppress the occurrence of partial discharge, and has an effect that it can be easily applied to a special high-voltage class static induction device.

The block diagram of the resin mold coil which shows 1st Example of this invention (The perspective view which cuts and shows the principal part) Enlarged sectional view of the main part FIG. 2 equivalent view showing a second embodiment of the present invention FIG. 2 equivalent view showing a third embodiment of the present invention. FIG. 2 equivalent view showing a fourth embodiment of the present invention.

(First embodiment)
The first embodiment of the present invention will be described below with reference to FIGS.
In FIG. 1, the resin mold coil 1 is formed in a substantially cylindrical shape or a substantially rectangular tube shape as a whole, and its center hole is fitted to a core leg of a transformer or a core of a reactor as a stationary induction device. Used.

  FIG. 1 shows one side portion of a cross section including the central axis of a cylindrical resin molded coil 1. The resin mold coil 1 is configured such that the mold layer 4 is formed by molding the entire coil 3 formed by arranging a plurality of annular unit coils 2 in the axial direction with an insulating resin. The unit coil 2 is configured by, for example, winding a magnet wire 5 formed by covering a conductor (copper wire) 5A having an oval cross section with an insulator 5B in an annular shape.

  As a feature of the resin mold coil 1 of the present embodiment, an electrostatic shield layer 6 is formed in close contact with the outer periphery of each unit coil 2 so as to surround the unit coil 2. The electrostatic shield layer 6 has a high resistance value (for example, 10 MΩ or more), and is formed by winding a conductive tape. The electrostatic shield layer 6 may be formed by applying a conductive paint or spraying a metal instead of the conductive tape. A plurality of unit coils 2 having the electrostatic shield layer 6 on the surface are arranged at predetermined intervals in the axial direction. These unit coils 2 are connected in series by a connecting wire (same configuration as the magnet wire 5) 7 as a connecting wire.

  Further, description will be made with reference to FIG. Among the unit coils 2, the uppermost unit coil 2 </ b> A corresponds to the inner peripheral portion 6 </ b> A of the electrostatic shield layer 6 that surrounds the unit coil 2 </ b> A of the insulator 5 </ b> Ba at the winding start end 5 a of the magnet wire 5 positioned inside. The part to be peeled is peeled off, and the conductor 5Aa of the part is electrically connected to the inner surface of the inner peripheral part 6A (the connection point is indicated by 8A). Further, in the uppermost unit coil 2A, a portion corresponding to the outer peripheral portion 6B of the electrostatic shield layer 6 surrounding the unit coil 2A of the magnet wire 5 positioned outside, for example, the insulator 5Bb at the winding end 5b, is peeled off. The portion of the conductor 5Ab is electrically connected to the inner surface of the outer peripheral portion 6B (the connection point is indicated by 8B).

  Further, in the unit coil 2B at the second stage of the unit coils 2, the outer peripheral portion 6B of the electrostatic shield layer 6 surrounding the unit coil 2B of the magnet wire 5 positioned outside, for example, the insulator 5Bb at the winding end 5b. The portion corresponding to is peeled off, and the conductor 5Ab of that portion is electrically connected to the inner surface of the outer peripheral portion 6B (the connection point is indicated by 8B). In this case, the winding end 5b of the second stage unit coil 2B is connected to the winding end 5b of the uppermost unit coil 2A by a connecting wire 7 serving as a connection line. Therefore, the outer peripheral portion 6B of the electrostatic shield layer 6 surrounding the unit coil 2A and the outer peripheral portion 6B of the electrostatic shield layer 6 surrounding the unit coil 2B are electrically connected via the conductor 5Ab, the jumper wire 7 and the conductor 5Ab. Is done.

  A portion corresponding to the inner peripheral portion 6A of the electrostatic shield layer 6 surrounding the unit coil 2 of the magnet wire 5 positioned inside the second stage unit coil 2B, for example, the insulator 5Ba of the winding start end 5a is peeled off. The conductor 5Aa in that portion is electrically connected to the inner surface of the inner peripheral portion 6A (the connection point is indicated by 8A). In this case, the winding start end 5a of the second stage unit coil 2B is connected to the winding start end (both not shown) of the third stage unit coil by a jumper wire 7. Therefore, the inner peripheral portion 6A of the electrostatic shield layer 6 that surrounds the unit coil 2B is electrically connected to the inner peripheral surface (none of which is not shown) of the electrostatic shield layer that surrounds the third stage unit coil by the crossover wire 7. It is connected.

  Hereinafter, similarly, the winding end of the odd-numbered unit coil, the winding end of the even-numbered unit coil, the winding start of the even-numbered unit coil, and the winding start of the odd-numbered unit coil. Are connected by a jumper wire 7, and the configuration of the odd-numbered unit coils is the same as that of the uppermost unit coil 2A, and the configuration of the even-numbered unit coils is the same as that of the second-stage unit coil 2B. It is the same.

  As described above, when the electrostatic shield layer 6 is provided on the surface of the unit coil 2, a capacitor is formed between the magnet wire 5 constituting the unit coil 2 and the electrostatic shield layer 6. The interval between the magnet wire 5 of the unit coil 2 and the electrostatic shield layer 6 is formed narrow. When the gap between the magnet wire 5 of the unit coil 2 and the electrostatic shield layer 6 is narrow and a floating capacitor exists between them, the potential of the electrostatic shield layer 6 that is a conductor having a high resistance value is the turn of each magnet wire 5. It is an approximate average value of the potential of the number.

  When the electrostatic shield layer 6 having such an average potential for each number of turns exists around the unit coil 2, the potential difference between the turn of each magnet wire 5 and the electrostatic shield layer 6 is different for each unit coil 2. It becomes a small value of 1/2 or less of the potential difference between both ends. Therefore, even if a minute gap exists in the unit coil 2 inside the electrostatic shield layer 6, it is difficult for discharge to occur between the magnet wire 5 and the electrostatic shield layer 6.

  Further, when the electrostatic shield layer 6 having the average potential of each turn of the magnet wire 5 exists around the unit coil 2, the potential difference between the turns of the magnet wire 5 belonging to the same unit coil 2 is not easily increased. The value is smaller than when the electrostatic shield layer 6 is not present. Accordingly, it is difficult for electric discharge to occur between the turns of the magnet wire 5 belonging to the same unit coil 2.

  About the outer part of the electrostatic shield layer 6, a high potential difference is generated between the electrostatic shield layer 6 and the ground (earth). However, the mold layer 4 at the outer portion of the electrostatic shield layer 6 has almost no microvoids and is at the same potential as the electrostatic shield layer 6. For this reason, unlike the case where the electrostatic shield layer 6 is not formed, the electric field strength in the outer portion of the electrostatic shield layer 6 is the same in every portion, and the phenomenon that a high electric field is locally generated does not occur. . Therefore, the partial discharge hardly occurs in the outer portion of the electrostatic shield layer 6.

  The conductor 5Aa at the winding start end 5a of the magnet wire 5 positioned inside the unit coil 2 and the conductor 5Ab at the winding end end 5b of the magnet wire 5 positioned outside the unit coil 2 are formed on the electrostatic shield layer 6 surrounding the unit coil 2. Since it is electrically connected to the inner peripheral portion 6A and the outer peripheral portion 6B, the potential of the electrostatic shield layer 6 can be fixed, and the insulation distance between the electrostatic shield layer 6 and the unit coil 2 can be set small. .

Furthermore, since the electrostatic shield layer 6 has a high resistance value (for example, 10 kΩ or more), it is possible to suppress eddy currents generated by the linkage of magnetic flux, and to reduce the loss generated in the electrostatic shield layer 6. Can be suppressed. For example, the loss generated in the electrostatic shield layer 6 is
(Voltage generated for one turn) ² / (resistance value of electrostatic shield layer in one turn direction)
Therefore, for example, if the generated voltage for one turn is 20 (V) and the resistance value of the electrostatic shield layer in one turn direction is 30 (kΩ), the generated power of the unit coil is about 0.013 (W). If it is a 1000kVA class transformer for electric power, it is a loss level without a problem.

  For this reason, in the resin molded coil 1 of the present embodiment, since the electrostatic shield layer 6 is provided, a portion where a high electric field is locally generated does not occur. Therefore, even if a minute gap exists in the unit coil 2, it is possible to suppress the occurrence of partial discharge, and it is easy to apply to a special high voltage class static induction device such as a 1000 kVA class transformer.

(Second embodiment)
FIG. 3 shows a second embodiment of the present invention, in which the same parts as those in the first embodiment are denoted by the same reference numerals.
The magnet wire 5 positioned outside the uppermost unit coil 2A, such as the winding end 5b, is made of a conductor (copper wire) on the magnet wire 5 positioned outside the second stage unit coil 2B, such as the winding end 5b. The connecting wire 9 is connected by a connecting wire 9, and the connecting wire 9 is covered with an electrostatic shield layer 6 </ b> C similar to the electrostatic shield layer 6. Accordingly, the winding end ends 5b and 5b of the unit coils 2A and 2B are electrically connected to the outer peripheral portions 6B and 6B of the electrostatic shield layers 6 and 6 surrounding the unit coils 2A and 2B via the crossover wires 9. (Connection points are indicated by 8D and 8D).

  The magnet wire 5 positioned inside the unit coil 2B, for example, the winding start end 5a is connected to the winding start end (none of which is not shown) of the magnet wire of the third stage unit coil via the crossover wire 9, and the transition The line 9 is covered with the electrostatic shield layer 6C. Accordingly, the winding end 5b of the unit coil 2B is electrically connected to the outer peripheral portion 6B of the electrostatic shield layer 6 surrounding the unit coil 2B via the connecting wire 9 (a connection point is indicated by 8C).

Hereinafter, similarly, the winding end of the odd-numbered unit coil, the winding end of the even-numbered unit, and the winding start of the even-numbered unit coil and the winding start of the odd-numbered unit coil The odd-numbered unit coils are connected by the line 9, and the configuration of the odd-numbered unit coils is the same as that of the uppermost unit coil 2A, and the configuration of the even-numbered unit coils is the same as that of the second-stage unit coil 2B. .
According to the second embodiment, the same effect as that of the first embodiment can be obtained. In particular, since the electrostatic shield layer 6C is also provided on the connecting wire 9, the effect of suppressing the occurrence of partial discharge between the grounds is achieved. Is even better.

(Third embodiment)
FIG. 4 shows a third embodiment of the present invention, in which the same parts as those in the second embodiment are indicated by the same reference numerals.
In the third embodiment, the unit coil 2 is formed by winding a magnet wire 10 formed by superposing a sheet-like conductor (copper sheet) 10A and a sheet-like insulator 10B. Each unit coil 2 is surrounded by an electrostatic shield layer 6, and an insulating resin 11 is filled between the electrostatic shield layer 6 and the unit coil 2 to form an insulating layer 11.

  In the unit coil 2, the magnet wire 10 located on the inner side, for example, the sheet-like conductor 10Aa at the winding start end 10a, and the magnet wire 10 located on the outer side, for example, the sheet-like conductor 10Ab at the winding end 10b, electrostatically surrounds the unit coil 2A. The shield layer 6 is connected to the inner surface of the inner peripheral portion 6A and the inner surface of the outer peripheral portion 6B by contact (connection points are indicated by 12A and 12B).

  The sheet-like conductor 10Ab at the winding end 10b in the uppermost unit coil 2A crosses the connecting line made of the sheet-like conductor (copper sheet) to the sheet-like conductor 10Ab at the winding end 10b in the second-stage unit coil 2B. The connecting wires 13 are connected by the wires 13 and are covered with the electrostatic shield layer 6C. The sheet-like conductor 10Aa at the winding start end 10a of the second-stage unit coil 2B is connected to the sheet-like conductor at the winding start end of the third-stage unit coil (both not shown) via the crossover wires 13. The connecting wire 13 is covered with the electrostatic shield layer 6C.

  In the same manner, the sheet-like conductor at the end of winding of the odd-numbered unit coil, the sheet-like conductor at the end of winding of the even-numbered stage, and the sheet-shaped conductor at the beginning of winding of the even-numbered unit coil and the odd-numbered stage. The sheet-like conductor at the winding start end of the unit coil of the eye is connected by the crossover wire 13, and the configuration of the odd-numbered unit coil is the same as that of the uppermost unit coil 2A. The configuration of the coil is the same as that of the second stage unit coil 2B.

  According to the third embodiment, the sheet-like conductor 10Aa at the winding start end 10a and the sheet-like conductor 10Ab at the winding end 10b of the unit coil 2 are surrounded by the inner peripheral portion 6A and the outer periphery of the shield layer 6 surrounding the unit coil 2. Since the portion 6B is connected, the electrostatic shield layer 6 having high resistance shares the potential by the high resistance, and the magnet wire 10 shares the potential by the number of turns. The potentials of the magnet wire 10 and the electrostatic shield layer 6 in the vicinity of the magnet wire 10 are substantially equal, so that it is not necessary to consider the insulation between the electrostatic shield layer 6 and the magnet wire 10, and the size of the unit coil 2 is minimized it can.

(Fourth embodiment)
FIG. 5 shows a fourth embodiment of the present invention, in which the same parts as those in the third embodiment are indicated by the same reference numerals.
In the fourth embodiment, the unit coil 2 is molded with a resin having a high resistance value (for example, 10 MΩ or more), and the electrostatic shield layer 14 surrounding the unit coil 2 is formed. Further, the sheet-like conductor 10Aa at the winding start end 10a and the sheet-like conductor 10Ab at the winding end end 10b of the unit coil 2 are formed on the inner surface of the inner peripheral portion 14A and the outer peripheral portion 14B of the electrostatic shield layer 14 surrounding the unit coil 2, respectively. It is connected to the inner surface by contact (connection points are indicated by 15A and 15B). The crossover wire 13 is covered with an electrostatic shield layer 14 </ b> C similar to the electrostatic shield layer 14.

According to the fourth embodiment, the same effect as that of the third embodiment can be obtained. In particular, the electrostatic shield layer in which the solid layer 11 and the electrostatic shield layer 6 of the third embodiment are integrated. Since it is configured as 14, the configuration becomes simple and the manufacture becomes easy.
The present invention is not limited to the embodiments described above and shown in the drawings, and it is needless to say that the present invention can be appropriately modified without departing from the scope of the invention.

  In the drawings, 1 is a resin mold coil, 2 (2A, 2B) is a unit coil, 3 is a coil, 4 is a mold layer, 5 is a magnet wire, 5A is a conductor, 5B is an insulator, 5a is a winding start end (inside (Magnet wire), 5b is the winding end (outside magnet wire), 5Aa and 5Ab are conductors, 6 and 6C are electrostatic shield layers, 6A is an inner periphery, 6B is an outer periphery, and 7 is a crossover (connection line). , 9 is a connecting wire (connection wire), 10 is a magnet wire, 10A is a conductor, 10B is an insulator, 10a is a winding start end (inner magnet wire), 10b is a winding end end (outer magnet wire), 10Aa and 10Ab is a sheet-like conductor, 13 is a crossover (connection line), 14 and 14C are electrostatic shield layers, 14A is an inner periphery, and 14B is an outer periphery.

Claims (7)

A coil in which a plurality of unit coils formed in a ring shape by winding a magnet wire are arranged in the axial direction and connected in series;
A plurality of electrostatic shield layers provided to individually surround the plurality of unit coils and having a high resistance value;
A resin mold layer that molds the whole of the plurality of electrostatic shield layers,
The magnet wire conductor positioned inside the unit coil and the magnet wire conductor positioned outside are electrically connected to the inner and outer peripheral portions of the electrostatic shield layer surrounding the unit coil. Resin mold coil. The unit coil is formed by winding a magnet wire composed of a sheet-like conductor and a sheet-like insulator,
The sheet-like conductor located inside the unit coil and the sheet-like conductor located outside are in contact with the inner surface of the inner peripheral portion and the inner surface of the outer peripheral portion of the electrostatic shield layer surrounding the unit coil. The resin molded coil according to claim 1. 3. The resin molded coil according to claim 2, wherein an insulating resin is filled between the unit coil and the electrostatic shield layer.   3. The resin molded coil according to claim 2, wherein the electrostatic shield layer is made of a resin having a high resistance value for molding the unit coil.   The resin-molded coil according to any one of claims 1 to 4, wherein the electrostatic shield layers of two adjacent unit coils are electrically connected by a connection line on the same potential side of both unit coils. .   6. The resin-molded coil according to claim 5, wherein the connection line that electrically connects the electrostatic shield layers of two adjacent unit coils is a connecting line that connects both unit coils in series.   7. The resin molded coil according to claim 6, wherein the crossover is made of a conductor and covered with an electrostatic shield layer similar to the electrostatic shield layer surrounding the unit coil.

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