JP2003318049A - Instrument transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an instrument transformer that can eliminate the need of expensive parts, such as the lead spacer, etc., or the attaching work of the parts, can provide a small-sized inexpensive VCT by easily making electrical connection in an outer box, and can reduce the installation area of the power receiving facility, such as the cubicle, etc., of a high-voltage customer. <P>SOLUTION: This instrument transformer 30 is composed of a transformer main body 10 and an iron core 10. This transformer 30 is constituted so that hole sections for passing connecting lead wires 40 may be formed in a junction formed at the center when two interment transformers 30 are placed side by side. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded transformer for an instrument, in which a primary winding and a secondary winding are covered with an insulating resin and an iron core is mounted.

[0002]

2. Description of the Related Art An instrument transformer is a current transformer.
sformer (hereinafter referred to as CT), voltage transformer (Voltage)
Transformer hereafter, referred to as VT, and voltage transformer for instrument (Voltage Current Transformer hereafter, VCT)
That is) is a generic term. The instrument transformer connects the primary winding to the bus of the high-voltage, large-current receiving equipment, and outputs a low voltage and low current according to the transformation ratio from the secondary winding to operate the relay and watt hour meter. Let

[0003] In particular, an instrument transformer for supply and demand of electric power is used in combination with an electric energy meter, a reactive electric power meter or a maximum demand electric power meter, and constitutes a part of weighing equipment involved in electricity rate trading. There is. To collect the correct electricity bill,
As an instrumental transformer, an electromagnetic instrumental transformer (for example, an electromagnetic VT and CT) having an excellent transformation ratio characteristic that causes only a negligible error is adopted.

Next, a VCT will be described with reference to the drawings as an example of the prior art of such an instrument transformer. FIG. 4 is an external view of the CT / VT, FIG. 5 is an electrical connection diagram of the VCT, FIG. 6 is an external view showing the external shape of the VCT, and FIG. 7 is an explanatory view illustrating the storage arrangement of the VCT in the power receiving facility, FIG. 8 is an explanatory diagram for explaining the wiring inside the VCT. VCT
Is installed, for example, in a power receiving facility of a 6.6 kV three-phase three-wire high-voltage customer. This VCT is constructed by integrally housing a VT and a CT assembled in a frame in an outer box.

For example, FIG. 8 shows each VT and CT alone.
It has an appearance as shown in (a), (b), and (c). CT300 is provided with the transformer main body 100 and the iron core 200, as shown in FIG. Transformer main body 10
As shown in FIGS. 4 (a) and 4 (b), reference numeral 0 denotes a cylindrical primary winding and a secondary winding that are concentrically arranged, and each of the primary and secondary windings has a primary terminal 110 and a secondary terminal. The terminal 120 is provided and is integrally formed with the insulating resin coating portion 130.
The insulating resin coating portion 130 is formed by curing an epoxy resin, which is a solid insulating material that has excellent physical characteristics such as electric insulation resistance and load resistance and stable chemical characteristics and is easy to manufacture and handle. is there. CT is the iron core insertion window 14
0, an iron core 200 (see FIGS. 8A, 8B, and 8C) is inserted.

These VTs and CTs are connected as shown in FIG. 5 to complete an instrument transformer as shown in FIG. In the connection diagram of FIG. 5, VT is a two-phase parallel connection at both ends of the primary winding between U-phase and V-phase and between V-phase and W-phase on the bus side, and CT is the primary winding. Two ends are respectively connected in series in two phases to the U-phase and the W-phase on the busbar side.

Connect the lead wire for connection from the VT primary winding to C
The primary side cable that is connected to the primary side cable connected to the T primary winding and is connected inside the outer box, and extends from the bushings 1200 arranged on both side surfaces of the outer box 1100 as shown in FIG. It is connected to the bus bar on the power supply side and the load side. On the other hand, a secondary side connection terminal 1300 in which lead wires are drawn from the secondary windings of VT and CT and arranged in a terminal is provided, and low voltage and low current transformed from the bus bar side are passed through the secondary side connection terminal 1300. , Electricity meter, reactive energy meter, maximum demand electricity meter, etc.

By the way, the above-mentioned VCT 1000 is shown in FIG.
In either the suspended type arrangement of (a) or the stationary type arrangement of FIG. 7 (b), the primary winding of the CT is connected to the primary side cable inside the VCT1000 when housed in a power receiving facility such as a cubicle. Due to the direct connection to the busbar through the size and shape and shape restrictions, a two-phase CT is placed in the upper stage and 2 in the lower stage.
There is no choice but to adopt a configuration in which the phase VTs are arranged and integrally housed in the outer box. When adopting such a configuration, the wiring has been devised.

This wiring will be described. 8 (a)-
As shown in (c), the connecting lead wire 500 is drawn from the primary winding of the lower VT (not shown) and wired, but the core of the CT (instrument transformer) 300 Two
In order to avoid a ground potential portion such as 00 or an outer box (not shown), it is fixedly held and routed via a fixture called a lead spacer 400 and connected to the primary side cable.

The lead spacer 400 is shown in FIG.
As is clear from (b) and (c), they are arranged at positions such that they are sandwiched between the two CTs 300, and the connecting lead wire 500 for VT connection is provided in the hole portion penetrating the lead spacer 400. It has a configuration of being inserted.

[0011]

The lead spacer 400 used in the prior art is required to have not only electrical insulation resistance but also load bearing capacity capable of withstanding bolt tightening force and compression force. Since the materials such as phenol resin, urea resin and melamine resin are limited, they were expensive parts.

Further, since the lead spacer 400 itself for sandwiching the VT connecting lead wire 500 is locked, CT3 is used.
The number of parts is large and the cost is high because the mounting frame processing is separately performed on the insulating resin coating part 130 of 00. Furthermore, the presence of the lead spacer 400 also contributes to the formation of a dead space by the insulating resin coating portion 130 which is inevitably formed in a substantially cylindrical shape from the VT and CT cylindrical primary windings and the secondary winding. However, the mutual distance between each CT and VT alone was extended more than necessary, and the outer box was also large.

An object of the present invention is to eliminate the need for expensive parts such as lead spacers or mounting work, and to easily make electrical connections inside the outer box while achieving a compact and low-cost VCT.
The purpose of the invention is to provide a transformer for measuring instruments that can reduce the laying area of high-voltage customer power receiving equipment such as cubicles.

[0014]

In order to solve the above-mentioned problems, the invention according to claim 1 covers the primary winding and the secondary winding to form a primary terminal, a secondary terminal and an iron core insertion window. An insulating resin coating portion, a joining projection portion provided on the insulating resin coating portion and having a joining surface formed therein, a plurality of linear groove portions provided substantially parallel to each other on the joining surface of the joining projection portion, and an iron core insertion And an iron core that penetrates through the window.

According to a second aspect of the invention, in the instrument transformer according to the first aspect, the linear groove portion is in a direction substantially parallel or substantially perpendicular to the extending direction of the primary terminal or the secondary terminal. It is characterized by being provided.

According to a third aspect of the invention, in the instrument transformer according to the first or second aspect, when the joining surfaces of the two instrument transformers are brought into contact with each other, holes are formed by the linear groove portions on both sides. A part is formed.

According to a fourth aspect of the invention, a plurality of current transformers, which are the transformers for measuring instruments according to the third aspect, are arranged in the upper stage, and a plurality of transformers for measuring instruments are arranged in the lower stage. It is a transformer transformer current transformer housed in one piece, and the lead wire for connection drawn out from the primary winding of the instrument transformer is inserted and fixed in the hole formed by joining two current transformers. It is characterized by holding.

According to a fifth aspect of the present invention, in the instrument transformer according to the fourth aspect, the current transformer is arranged in two phases in the upper stage and the transformer for instrument is arranged in two phases in the lower stage.

[0019]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a transformer for an instrument of this embodiment, and FIG. 2 is a block diagram of a transformer main body. More specifically, the instrument transformer is used in the VCT arranged in the power receiving equipment of the 6.6 kV three-phase three-wire high-voltage customer described above with reference to FIGS. The connection lead wire drawn from the primary winding of the VT is inserted and fixedly held in the side surface closed space formed by arranging CT in two phases.

In this case, the two-phase CT is shown in FIG.
As shown in (a) and (b), the transformer main body 10 and the iron core 2
A pair of 0 instrument transformers 30 are arranged, and a connecting lead wire 40 is arranged between the pair of instrument transformers 30. As shown in FIG. 2, the transformer main body 10 includes an insulating resin coating portion 1, a joining projection portion 2, a primary terminal 3, a secondary terminal 4, an iron core insertion window 5, a linear groove portion 6, and a joining surface 7. ing.

The insulating resin coating portion 1 is formed by coating an insulating resin typified by an epoxy resin in a state in which a primary winding and a secondary winding (not shown) are stacked. When cured, the primary terminal 3, the secondary terminal 4, and the iron core insertion window 5 are integrally formed.

The joining projection 2 is integrally formed so as to project from the insulating resin coating portion 1, but has at least a height such that the linear groove portion 6 can be formed. Epoxy resin, which is a solid insulator that is integrally coated on the winding, has electrical insulation performance that is superior to lead spacers and load resistance that can withstand bolt tightening force.
Is required to form a slight height, and the dead space generated between the pair of instrument transformers 10 shown in FIG. 1B is reduced.

The primary terminal 3 is a terminal electrically connected to a primary winding (not shown), and is formed in a state of protruding from the insulating resin coating portion 1. The secondary terminal 4 is a terminal electrically connected to a secondary winding (not shown), and is formed in a state of protruding from the insulating resin coating portion 1.

The iron core insertion window 5 is provided with an iron core 20 (see FIG. 1 (a),
(See (b)). The linear groove portion 6 is
The connecting lead wire 40 (see FIGS. 1A and 1B) has a substantially semicircular cross-section so that the covered portion can come into contact with the joint surface 7 which is the side surface of the joint protrusion 2. Formed on. A plurality of (4 in FIG. 1 and FIG. 2) linear grooves 6 are formed on the surface of the joint surface 7 and are provided so as to be substantially parallel to each other.

As is apparent from FIGS. 1 and 2, the linear groove portion 6 is in a direction substantially parallel to the extending direction of the primary terminal 3 and substantially perpendicular to the extending direction of the secondary terminal 4. It is provided in. This is because the cables connected to the primary terminal 3 and the secondary terminal 4 are also wired so as to extend in the extending direction. As a result, the connecting lead wire 40 and the cable connected to the primary terminal 3 are wired substantially parallel to each other, and the connecting lead wire 40 and the cable connected to the secondary terminal 4 are wired substantially vertically. There is an advantage that the wiring is arranged as a whole.

The joint surface 7 is a surface that comes into contact with another transformer main body 10 and is joined here to form a pair. As is apparent from FIGS. 1 and 2, the joint surface 7 is provided in a direction parallel to the extending direction of the primary terminal 3 and the extending direction of the secondary terminal 4. Thus, the connecting lead wire 40 is designed so as not to intersect with the cable extending in the extending direction of the primary terminal 3 and the cable extending in the extending direction of the secondary terminal 4.

Next, the arrangement in the VCT installed in the power receiving equipment of the 6.6 kV three-phase three-wire high-voltage customer will be described. Although not shown, the cylindrical primary winding and the secondary winding are concentrically arranged and covered with an insulating resin such as epoxy resin, and an iron core is attached to the VT (for the instrument of FIGS. 8A, 8B, and 8C). The same shape as the transformer 300) is arranged in the lower stage. Two ends of the primary winding of the VT are connected in parallel to each other between the U-phase and the V-phase and the V-phase and the W-phase on the bus side.

Connecting lead wires 40 are connected to connect both ends of the primary winding of each VT to the U-phase and V-phase primary cables and the V-phase and W-phase primary cables respectively in parallel.
On the other hand, when the side surfaces of two CTs (see the instrument transformer 30 in FIGS. 1A and 1B) are brought into contact with each other, a hole is formed by the linear groove portion 6 having a cross section on both sides of a substantially semicircle. It The connecting lead wire 40 drawn out from the VT primary winding is inserted through this hole and fixedly held. Then, each CT arranged in the upper two phases is connected from the K terminal of the primary winding to the power supply side busbar,
Connect the U-phase and W-phase so that the L terminal is connected in series to the load side bus
The primary cable of the phase is connected (see Figure 5).

The V-phase primary side cable is inserted from the power source side bus bar to the load side bus bar through the bushing through the outer box. The U-phase, V-phase, and W-phase primary side cables extend to the outside so as to be connected to the busbar side via bushings arranged in the outer boxes on the power supply side and the load side (see FIG. 6).

The present embodiment has been described above. In addition,
The linear groove 6 is not limited to a semicircle in cross section, but may be a Δ-shaped cross section, a □ -shaped cross section, or any other shape, and the protrusions 2 for joining and the linear groove 6 are also made of resin casting metal such as CT. It can be easily formed by substituting a part of the mold.

Furthermore, the linear groove portion 6 of the joint surface 7 is
VCT connection lead wire 4 housed in the outer box as described above
The present invention is not limited to the use for electrical connection by means of 0, but for mechanical structures, for example, metal rods, bolts, etc. are pressed into the recesses to install and fix the instrument transformer alone, or simply use the rope. Etc. may be locked in the recessed portion and used for transporting and transporting a single instrument transformer.

In the present embodiment as described above, by forming the insulating resin coating portion 1 having the bonding protrusions 2 using epoxy resin, a frame for fixing the CT or the like alone, including the VT, to each other (not shown). No.) can be assembled and placed close to each other to reduce the size while inserting and fixing the connecting lead wire 40, and at the same time, it is possible to reduce expensive parts such as lead spacers and mounting work.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a configuration diagram of a transformer main body of the instrument transformer of the present embodiment. The transformer main body 10 'of the present embodiment is the same as that of the first embodiment except for the linear groove portion 6', and the duplicated description thereof will be omitted.

This linear groove portion 6'is formed so as to be perpendicular to the direction of the linear groove portion 6 of the first embodiment described with reference to FIG. In this case, as shown in FIG. 3, it suffices to project the joining projection 2 only by the minimum necessary amount, and when the pair of left and right forming device main bodies 10 ′ are joined, a dead space was formed in the first embodiment. A hole for inserting the connection cable is formed at the position to reduce the dead space.

The linear groove portion 6'is not limited to the Δ-shaped section, but may be a semi-circular section, a □ -shaped section, or an arbitrary shape. It can be easily formed by substituting a part of the resin casting mold such as. Furthermore, the linear groove portion 6'of the joint surface 7 is also used for mechanical structures such as metal rods and bolts.
May be pressed against the recessed portion to install and fix the single instrument transformer, or the rope may simply be locked in the recessed portion and used for transporting and transporting the single instrument transformer.

[0036]

According to the present invention, the insulating resin coating portion formed in a substantially cylindrical shape reduces the dead space formed in the close arrangement, and eliminates expensive parts such as lead spacers or mounting processing. It is possible to provide a small-sized and low-cost VCT while easily performing electrical connection inside the outer box, and thus to provide an instrument transformer capable of reducing the installation area of a high-voltage consumer power receiving facility such as a cubicle.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an instrument transformer according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a transformer main body.

FIG. 3 is a configuration diagram of a transformer main body of an instrument transformer according to a second embodiment of the present invention.

FIG. 4 is an external view of a CT / VT.

FIG. 5 is an electrical connection diagram of VCT.

FIG. 6 is an external view showing an outer shape of a VCT.

FIG. 7 is an explanatory diagram illustrating a storage arrangement of a VCT in a power receiving facility.

FIG. 8 is an explanatory diagram illustrating wiring inside a VCT.

[Explanation of symbols]

1 Insulating resin coating 2 Protrusions for joining 3 primary terminals 4 secondary terminals 5 Iron core insertion window 6,6 'Straight groove 7 Bonding surface 10,10 'transformer body 20 iron core 30 Instrument transformer 40 connection lead wire

Claims (5)

[Claims] 1. An insulating resin coating portion which covers the primary winding and the secondary winding to form a primary terminal, a secondary terminal and an iron core insertion window, and a joint surface which is provided on the insulating resin coating portion. A transformer for an instrument, comprising: the joint projection formed as described above; a plurality of linear groove portions provided substantially parallel to each other on a joint surface of the joint projection; and an iron core penetrating an iron core insertion window. 2. The instrument transformer according to claim 1, wherein the linear groove portion is provided in a direction substantially parallel or substantially perpendicular to the extending direction of the primary terminal or the secondary terminal. Transformers for measuring instruments. 3. The instrument transformer according to claim 1 or 2, wherein when the joining surfaces of the two instrument transformers are brought into contact with each other, a hole is formed by the linear groove portions on both sides. A transformer for instruments characterized by. 4. An instrument transformer in which a plurality of current transformers, which are the instrument transformers according to claim 3, are arranged in an upper stage and a plurality of instrument transformers are arranged in a lower stage, respectively, and are integrally housed in an outer box. The current transformer is characterized in that the connecting lead wire drawn from the primary winding of the instrument transformer is fixedly held in the hole formed by joining the two current transformers. Transformers for measuring instruments. 5. The instrument transformer according to claim 4, wherein the current transformer is arranged in two phases in the upper stage and the transformer for instrument is arranged in two phases in the lower stage.