JP2001267157A - Current transformer for high voltage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-quality current transformer having such a structure that can suppress corona discharge failure and insulation failure by an extremely simplified manufacture step. SOLUTION: This current transformer for high voltage is formed by connecting mutually a secondary winding 3 that a conductive wire 2 is wound around a closed magnetic circuit core 1, and a primary conductor 5 penetrating a hollow part 4 of the secondary winding 3, and the primary conductor 5 comprises a conductor 6 forming a core and an insulator 9 which exposes both end surfaces 7 of the conductor 6 and covers the side surfaces of the conductor 6. The secondary winding 3 in the primary conductor 5 is fixed at a specified creeping distance apart from both end surfaces of the conductor 6, and the thickness of either of sides directing to the end surface from the fixation position in the primary conductor 5 is set enough to pass the hollow part 4 of the secondary winding 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage current transformer.

[0002]

2. Description of the Related Art In a conventional high voltage current transformer, as shown in FIG. 13, an entire primary winding and a secondary winding are molded with an insulating resin and cut into hollow portions of the primary winding and the secondary winding. It has a structure in which the core is inserted and inserted.

[0003]

In order to secure the insulation between the primary winding and the secondary winding under a high voltage with such a structure, accurate positioning is required before both are molded with an insulating resin. It is necessary to perform the arrangement with sufficient clearance, but the operation is extremely complicated and difficult, and when the object having the complicated shape is resin-molded,
Since voids are easily generated in the resin mold portion, it has been a factor of causing corona discharge failure and insulation failure.

The present invention has been made in view of the above circumstances, and has as its object to provide a high-quality high-voltage current transformer having a structure capable of suppressing a corona discharge failure through an extremely simple manufacturing process. I do.

[0005]

Means for Solving the Problems A high voltage current transformer according to the present invention, which has been made to solve the above-mentioned problems, has a secondary winding portion formed by winding a conductive wire around a closed magnetic circuit core, and the secondary winding portion. Primary conductors penetrating the hollow part of the secondary winding part are connected to each other,
The primary conductor is a conductive part forming a core, and an insulating part that exposes both end surfaces of the conductive part (may be a part or all) and covers a side surface of the conductive part. And the fixed position of the secondary winding portion in the primary conductor portion is set at a position separated by a predetermined creeping distance from both end surfaces of the conductive portion, and the fixed position in the primary conductor portion The thickness of one of the sides from the position toward the end face is set to a thickness that can pass through the hollow portion of the secondary winding portion.

[0006] Further, the secondary winding portion is formed by connecting a conductive wire wound around a closed magnetic path iron core and a double primary conductor portion penetrating through a hollow portion of the secondary winding portion. The primary conductor portion is composed of a conductive portion that forms a core, and an insulating portion that exposes both end surfaces of the conductive portion and covers the side surface of the conductive portion, and fixes the secondary winding portion in the primary conductor portion. The position is set at a position separated by a predetermined creepage distance from both end surfaces of the conductive portion, and the thickness of at least the phase connecting side of the primary conductor portion from the fixed position toward the end surface is the secondary The structure may be such that the thickness is set so as to pass through the hollow part of the winding part.

Here, the high voltage refers to a voltage exceeding 600 V. The predetermined creepage distance is a creepage distance suitable for securing an insulation state set on specifications or standards,
If the specification or the standard changes, it naturally changes. Therefore, as long as such a creepage distance is secured, the region from both end surfaces of the conductive portion in the primary conductor portion to the fixed position of the secondary winding portion may be formed in any shape. However, in order to connect the two, the fixed portion of the primary conductor must be inserted into the hollow portion of the secondary winding, so that either one of the primary conductor toward the end face from the fixed position in the primary conductor It is indispensable to have a structure in which the thickness of the side is set to a thickness that can pass through the hollow portion of the secondary winding portion. When using two primary conductors,
The edge surface distance is ensured for both of the phase-coupled primary conductors, and the thickness of any one side of the primary conductor from the fixed position toward the end face, that is, at least the thickness of the phase-coupled side. However, it is indispensable for the structure to have a thickness set so as to pass through the hollow portion of the secondary winding portion.

The shapes of the primary conductor and the conductive portion may be appropriately selected according to the specification, such as a rotating body, a plate, or a member having an irregular cross section. Further, the insulation between the secondary winding part and the primary conductor part is sufficient if at least the insulation part having a thickness suitable for the specification is formed and placed on the primary conductor part side. For the sake of convenience, an insulating section having an appropriate thickness may be provided on the surface of the secondary winding section. Incidentally, the structure of the insulating portion formed on the surface of the secondary winding portion may be a structure filled with an insulating material, a structure having a gap, or a structure using both of them.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a current transformer according to the present invention will be described below with reference to the drawings. In the current transformer according to the present invention, a secondary winding part 3 formed by winding a conductive wire 2 around a closed magnetic circuit core 1 and a primary conductor part 5 penetrating a hollow part 4 of the secondary winding part 3 are mutually connected. They are connected.

The primary conductor portion 5 includes a conductive portion 6 made of copper or other high-quality conductive material forming a core, and an insulating portion that exposes both end surfaces 7 of the conductive portion 6 and covers a side surface 8 of the conductive portion 6. 9, the fixed position of the secondary winding part 3 in the primary conductor part 5 is set to an intermediate part in the longitudinal direction of the primary conductor part 5. The secondary winding part 3 includes a coil 11 in which the conductive wire 2 is wound around the entire area of the ring-shaped closed magnetic core 1 in an orderly manner. ,
The diameter and shape of the hollow part 4 are determined so that the primary conductor part 5 is located at the center of the hollow part of the secondary winding part 3.

The thickness of the insulating portion 9 is substantially uniform in the radial direction at each position in the longitudinal direction of the primary conductor portion 5, and the fixing position of the secondary winding portion 3 is accurately determined at the fixing position. Fixing means are provided as appropriate. The specific thickness of the insulating portion 9 formed on the primary conductor portion 5 varies depending on its specifications. However, for those used for high voltage as in the present invention, the thickness between the conductive portion 6 and another conductor is different. It is said that it is necessary to provide a distance of about 10 mm as a space distance (a distance interposed only with air), so that the thickness corresponding to the space distance can be secured in relation to the structure of the adjacent conductor. It is desirable to adopt it.

A first embodiment shown in FIG.
The secondary winding 3 is fixed with an adhesive made of silicon or the like. As shown in FIG. 2, the primary conductor portion 5 in this example insulates a resin film (epoxy or the like) having a substantially uniform thickness over the entire side surface 8 of the conductive portion 6 formed by molding copper into a columnar shape having a uniform diameter. A primary terminal 12 for connecting and fixing an external bus bar, an electric cable or the like is provided at the center of the exposed both end surfaces 7. Also, the secondary winding part 3 of this example
Replaces the coil 11 as shown in FIGS.
By loading the insulating case 13 having a circular upper portion and a rectangular lower portion capable of supporting the hollow portion and storing it so as not to cause blurring, the insulating portion 10 is formed by the insulating case 13 and the void formed inside the insulating case 13. It is what constituted. A secondary terminal 15 for connecting a lead wire 14 drawn from both ends of the conductive wire 2 is fixed to the insulating case 13. A predetermined portion provided on a switchboard or the like is provided on an end surface of the rectangular portion. A screw hole 16 is provided for fixing to a mounting plate.

In the primary conductor portion 5 having no irregularities on the surface as in this example, the shortest distance from both end surfaces 7 of the conductive portion 6 to the fixing position of the secondary winding portion 3 is a predetermined (specification or standard). Creepage distance).
When the current transformer is manufactured with a minimum size, the lengths of the primary conductor 5 at the fixed position of the secondary winding 3 are equal to each other. On the other hand, the second
In the embodiment, one of the side surfaces of the primary conductor portion 5 at the fixed position of the secondary winding portion 3 bulges largely, so that the creepage distance is important, so that the side having the bulge portion 22 is provided. The length is somewhat reduced, which contributes to the miniaturization of the current transformer, and the bulging portion 22 functions as a stopper for preventing the secondary winding portion 3 from entering, so that the mutual positioning can be accurately performed. It will also help you to do. However, when both the primary conductor 5 and the secondary winding 3 at the fixed position are bulged beyond the diameter of the hollow portion 4 of the secondary winding 3, the primary conductor 5 and the secondary winding 3 Since it becomes difficult to assemble both the wire portion 3,
The thickness of one of the sides is the hollow portion 4 of the secondary winding portion 3.
It must be set to a thickness that can pass through.

The third embodiment shown in FIG. 6 and the fourth embodiment shown in FIG. 7 have a structure which facilitates assembly and which can reduce the length of the primary conductor portion 5. It is an example.

In the third embodiment, the diameter of both sides of the primary conductor 5 at the fixed position of the secondary winding 3 is set to be smaller than the diameter of the secondary winding 3 that can pass through the hollow portion 4. In addition, the groove 17 is formed in a bellows shape while maintaining the shape of the primary conductor 5 as a rotating body. This makes it possible to reduce the actual size (length) of the primary conductor 5 without reducing the creeping distance between the end face and the fixed position of the primary conductor 5.

The fourth embodiment is different from the first embodiment in that the bulging portion 2 is provided on one side of the primary conductor 5 at a position where the secondary winding portion 3 is fixed.
2 and the other is a hollow part 4 of the secondary winding part 3.
The bellows-like groove 17 is formed while maintaining the diameter of the primary conductor portion 5 as a rotating body while setting the diameter to be equal to or smaller than the diameter allowing passage. Even with such a structure, the actual size (length) of the primary conductor 5 can be reduced without reducing the creepage distance between the end face and the fixed position in the primary conductor 5 as in the third embodiment. it can.

The secondary winding section 3 does not necessarily need to be loaded in the insulating case 13 as described above, but it is desirable to take as much insulation measures as possible to prevent an accident due to contact with an external conductor. The simplest means for achieving such an object is a means for forming the insulating portion 10 by winding an insulating tape 18 as shown in FIG. 8, but the manufacturing operation is simple and the structure is high in quality. As a highly reliable means, as shown in FIG. 9, the coil 11 is molded with an insulating resin such as an epoxy resin into a shape advantageous for assembling and disposing. Is formed. In addition to the above, there is a method of loading the secondary winding portion 3 into the insulating case 13 as described above, and further filling and solidifying a resin such as epoxy into a gap formed inside the insulating case 13.

As described above, the method of manufacturing the primary conductor portion 5 and the secondary winding portion 3 separately requires an operation of forming insulating portions 9 and 10 by resin molding for electrically insulating each of them from outside. Be easy. That is, by separately forming both, the respective shapes are extremely simplified, and the generation of voids and insulation failure in the resin molding operation can be significantly suppressed, so that the operation contents can be simplified and the operation efficiency can be greatly increased. .

As a fixing means for connecting the primary conductor section 5 and the secondary winding section 3, for example, a groove 21 in which an O-ring 19 is fitted is provided on a side surface of the primary conductor section 5 as shown in FIG. A structure for restricting the displacement of the secondary winding portion 3 by the O-ring 19 (hereinafter, referred to as a structure using the O-ring 19).
Also, as shown in FIG. 10B, the side surface of the primary conductor portion 5 and the unevenness formed on the surface of the secondary winding portion 3 facing the hollow portion 4 are engaged with each other (including screwing) so as to be mutually engaged. A structure that regulates displacement (hereinafter, referred to as a structure in which unevenness engages),
As shown in FIG. 10 (c), an inclined portion 20 is provided on the side surface of the primary conductor portion 5 so as to increase in diameter in one longitudinal direction, and the primary conductor portion is fixed at the position where the secondary winding portion 3 is fixed. 5
The side surface of the secondary winding portion 3 and the surface facing the hollow portion of the secondary winding portion 3 are in close contact with each other, so that the secondary winding portion 3 in one direction is formed.
And a means using a structure that regulates the positional deviation to the other side by adopting a structure using the O-ring 19 (or a structure in which the unevenness is engaged). Any existing fixing means such as a means using a split pin may be used.

As shown in FIG. 11, two primary conductors 23 of the current transformer are connected to each other through the hollow portion of the secondary winding part 3, and the two primary conductors 23 are provided in the two primary conductors 23, 23. By clamping and fixing the secondary winding portion with the bulging portion 22 shown in the second and fourth embodiments, the primary conductor portions 23, 23 and the secondary winding portion are provided without newly providing fixing means. The connection state with the wire portion 3 can be maintained (fifth embodiment). At this time, it is not possible to secure a predetermined creepage distance by the above-described various means from both end surfaces 7, 7 of the conductive portions of the primary conductor portions 23, 23 forming a double unit to the fixing position of the secondary winding body 3. From the beginning, the end surfaces 7, 6 of the conductive portions 6, 6 on the phase-coupled side
7, that is, from the end faces 7, 7 which are in close contact with each other,
For example, the conductive portions 6, 6
The predetermined creepage distance must be ensured by adopting a means or the like in which the meshing of the insulating portions 9 and 9 attached to the side surfaces is made into a mutually intertwined structure.

As a method of connecting the successive primary conductive portions 23, 23, the two conductive portions 6, 6 are brought into close contact with each other in order to ensure a good connection and conduction between the conductive portions 6, 6. It is preferable to provide a male screw on one end and a female screw on the other end of the side end surfaces 7, 7 and screw them together (see FIG. 11). Further, a method (see FIG. 12) of forming the male screw and the female screw in the insulating portions 9, 9 may be employed. Further, since the two primary conductors 23, 23 having such connection means are connected through the hollow portion of the secondary winding part 3 as described above, the two primary conductors connected in phase are connected to each other. Needless to say, it is necessary to set the thickness of the connecting side of 23 and 23 to a thickness that can pass through the hollow portion of the secondary winding portion 3.

[0022]

As described above, the current transformer according to the present invention has a structure in which the primary conductor and the secondary winding are separately manufactured and can be integrated later, so that the shapes of the respective current transformers are extremely simple.
The most efficient molding operation as a method of forming the insulating portion can be easily and carefully performed. As a result, not only can the manufacturing cost be reduced due to the improvement in work efficiency and the dramatic improvement in product yield, but also corona discharge failure and insulation failure, which often occur in the conventional mold resin part, are greatly reduced. In addition, a remarkable practical effect can be achieved in terms of quality.

[Brief description of the drawings]

1A and 1B are a side view and an end view showing a first embodiment of a current transformer according to the present invention.

FIGS. 2A and 2B are an end view and a cross-sectional view of a primary conductor of the current transformer shown in FIG.

3 (a), (b) and (c) are an end view, a side view and a bottom view of a secondary winding part of the current transformer shown in FIG.

4 (a), (b) and (c) are schematic explanatory views of the internal structure of FIG. 3 seen through from the end face side, the side face side and the lower face side.

5A and 5B are a side view and an end view showing a second embodiment of the current transformer according to the present invention.

6A and 6B are a side view and an end view showing a third embodiment of the current transformer according to the present invention.

FIGS. 7A and 7B are a side view and an end view showing a fourth embodiment of the current transformer according to the present invention.

8 (a), (b), and (c) are an end view, a side view, and a bottom view showing an example of a secondary winding unit used in the current transformer according to the present invention.

9 (a), (b), and (c) are schematic explanatory views of the internal structure of an example of a secondary winding unit used in the current transformer according to the present invention, seen from the end face side, the side face side, and the lower face side.

FIGS. 10 (a), (b) and (c) are schematic explanatory views illustrating fixing means provided in the current transformer according to the present invention.

FIG. 11 is a sectional view showing a fifth embodiment of the current transformer according to the present invention.

FIG. 12 is a sectional view showing a fifth embodiment of the current transformer according to the present invention.

13A and 13B are a side view and an end view showing an example of a conventional current transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed magnetic circuit core 2 Conductive wire 3 Secondary winding part 4 Hollow part 5,23 Primary conductor part 6 Conductive part 7 End face 8 Side face 9,10 Insulating part

Claims (3)

[Claims] 1. A secondary winding part (3) formed by winding a conductive wire (2) around a closed magnetic circuit core (1), and penetrates a hollow part (4) of the secondary winding part (3). The primary conductors (5) are connected to each other, and the primary conductors (5) are formed by exposing the conductive portions (6) forming a core and both end faces (7) of the conductive portions (6). An insulating part (9) covering a side surface (8) of the conductive part (6), and a fixing position of the secondary winding part (3) in the primary conductor part (5) is the conductive part (6). And the thickness of at least one side of the primary conductor portion (5) from the fixed position toward the end surface is set to be equal to the secondary winding. A high-voltage current transformer set to have a thickness that allows passage through the hollow part (4) of the wire part (3). 2. A secondary winding part (3) formed by winding a conductive wire (2) around a closed magnetic path iron core (1), and penetrates a hollow part (4) of the secondary winding part (3). Two primary conductors (23, 2
3) are connected to each other, and the primary conductor (23, 2)
3) a conductive portion (6) that forms a core, and an insulating portion (9) that exposes both end surfaces (7) of the conductive portion (6) and covers a side surface (8) of the conductive portion (6). And the fixed position of the secondary winding part (3) in the primary conductor part (23, 23) is at a position separated by a predetermined creepage distance from both end faces (7) of the conductive part (6). The thickness of at least the side of the primary conductor portion (23, 23) connected to the end face from the fixed position in the primary conductor portion (23, 23) passes through the hollow portion (4) of the secondary winding portion (3). Current transformer for high voltage set to the thickness that can be made. 3. The said secondary winding part (3) is provided with the insulating part (10) which covers the surface of said secondary winding part (3).
2. The high-voltage current transformer according to item 1.