JPH087609Y2 - Distribution transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a structure for extracting a bushing in a distribution transformer such as a pole transformer.

[Prior Art] In a conventional distribution transformer, a secondary bushing may be used by arranging two bushings in parallel for the same phase (same pole) due to the current capacity. Only one bushing was provided for each phase.

In this case, if the primary side of the transformer fails, naturally the secondary side also fails.

If two primary bushings are installed in parallel for each phase and two electric wires can be independently attached and detached,
It is possible to prevent a power failure on the secondary side of the transformer when performing construction on the secondary side.

That is, when a permanent power line connected to one of the primary bushings is scheduled to undergo a power failure in advance due to construction work, etc., by connecting a temporary line previously connected to another power source to the other primary bushing, It is possible to avoid power failure on the secondary side of the transformer.

[Problems to be Solved by the Invention] In the conventional ordinary transformer, if the primary side is out of power, naturally 2
The next side also has a power outage. As already mentioned, if two primary bushings are installed in parallel for each phase, power can be supplied from the temporary line even if there is a power outage on the permanent line due to construction work, etc., so a power outage on the secondary side of the transformer can be avoided. .

However, when two primary bushings are arranged side by side for each phase, a large number of primary bushings are concentrated and arranged in a partial area, so that it is unavoidable that the electric wires are congested.

Therefore, it becomes difficult to attach and detach the electric wire to and from the primary bushing, and the attaching and detaching work imposes a great mental burden on the worker since the attaching and detaching work is a live line work.

The purpose of the present invention is to allow the two wires to be attached and detached independently for each phase on the primary side to prevent the power failure on the transformer secondary side when the permanent wire side fails. An object of the present invention is to provide a distribution transformer that enables easy attachment / detachment work of an electric wire to / from a primary side bushing.

[Means for Solving the Problem] The present invention relates to a distribution transformer in which a primary bushing and a secondary bushing are attached to a transformer tank whose upper end opening is closed by a main cover.

In the present invention, the primary bushing of each phase is composed of two types of primary bushings, a primary bushing for a permanent wire and a primary bushing for a temporary wire.

The primary bushing for the permanent wire and the primary bushing for the temporary wire are commonly connected in the transformer tank and connected to the transformer winding in the tank.

The primary bushing for the permanent wire is attached to the side wall of the transformer tank, and the primary bushing for the temporary wire is attached to the main cover.

It is preferable to use a bayonet type bushing as the primary bushing.

[Operation] When the primary bushing of the transformer is configured by the primary bushing for the permanent wire and the primary bushing for the temporary wire as described above, power is supplied by the temporary wire even if the permanent wire fails on the primary side. Therefore, the transformer can be operated without interruption.

Also, if the primary bushing for permanent wire is attached to the side wall of the transformer tank and the primary bushing for temporary wire is attached on the main cover, the wires will not be congested in the work space, so the wire attachment / detachment work will be easy. It can be carried out.

Further, when the insertion type bushing is applied to the primary bushing of the transformer as described above, the work of attaching and detaching the electric wire can be performed safely in a short time.

Embodiments Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

1 and 2 are a front view and a plan view, respectively, showing an embodiment of the present invention.

The distribution transformer (hereinafter, simply referred to as a transformer) in this embodiment is a three-phase pole transformer, and this pole transformer is configured by connecting two single-phase transformer bodies in a V-connection. .

Since the feature of the present invention lies in the structure for drawing out the primary side circuit, the primary side portion will be mainly described.

The transformer bushing is divided into a primary bushing and a secondary bushing in terms of input and output, but the secondary bushing is composed of two types of bushings: a permanent wire bushing and a temporary wire bushing.

Primary bushings for permanent lines are used during normal operation 1
A secondary bushing, which is connected to a high-voltage side permanent wire (hereinafter referred to as a permanent wire).

The temporary bushing primary bushing is a bushing that is temporarily used to operate the transformer uninterruptibly when a power outage occurs in the permanent wire due to construction work. Connected).

Power is supplied by the temporary wire while the permanent wire is out of power, and power is supplied uninterruptedly to the low voltage side wire connected to the secondary bushing.

1 and 2, Ta is a transformer tank, and this transformer tank has a structure in which the upper end opening of the tank body is closed by a main cover Ca. 2 inside the transformer tank Ta
A three-phase transformer configured by connecting V-connections of the single-phase transformer of the stand is housed.

Primary bushings B1u, B1v, B1w for permanent lines are installed on the upper side of the tank Ta of the transformer, and secondary bushings B2u, B2u, on the upper side of the tank on the side substantially opposite to the pull-out direction of the primary bushings for permanent lines. B2v, B2w and B2n are installed.

The main cover Ca has a temporary wire bushing B1u ′, B1v ′, B1
w'is mounted with the bushing shaft in a substantially vertical direction.

The main cover Ca is provided with a handhole, and the handhole is closed by a handhole cover Ch. Internal connection of the temporary wire bushing is made through this handhole cover Ch.

FIG. 3 is an internal connection diagram of this embodiment. The single-phase transformer main body Tr1 (first single-phase transformer main body) has a primary winding W1a and a secondary winding W2a, and the secondary winding W2a is a winding with a midpoint lead. The single-phase transformer main body Tr2 (second single-phase transformer main body) has a primary winding W1b and a secondary winding W2b. The two single-phase transformer bodies Tr1 and Tr2 are V-connected on both the primary and secondary sides.

U1, V1 and W1 are three-phase primary side terminals, and U2, V2, W2 and n are secondary side terminals. U of these secondary terminals
2, V2 and W2 are three-phase secondary side terminals, and n is a secondary side neutral point terminal used by being grounded. The neutral terminal is the secondary winding W2
It is drawn from the midpoint of a.

The primary side terminal U1 is connected to both the primary bushing B1u for the permanent wire and the primary bushing B1u ′ for the temporary wire. The primary side terminal V1 is connected to both the primary bushing B1v for the permanent wire and the primary bushing B1v 'for the temporary wire. The primary side terminal W1 is connected to both the primary bushing B1w for a permanent wire and the primary bushing B1w 'for a temporary wire.

The secondary side terminals U2, V2, W2 and the secondary side neutral point terminal n are connected to the secondary bushings B2u, B2v, B2w, B2n, respectively.

In the transformer according to the present invention, the transformer can be made uninterrupted even when the primary permanent wire is cut off due to construction work or the like. The work steps in that case are shown in FIG.

In Fig. 4, B1 is the primary bushing for permanent lines B1u, B1v,
B1w is a general representation, and B1 'is a general representation of temporary primary bushings B1u', B1v ', B1w'. B2 generally represents the secondary bushings B2u, B2v, B2w, B2n.

L1 and L1 'are a permanent wire and a temporary wire, respectively, and L2 is a low voltage side wire.

In FIG. 4, in order to avoid congestion, symbols of bushings and electric wires are shown only for one phase, and others are omitted. Further, in FIG. 4, circuits in which electricity is being supplied (current flows) are shown by thick lines, and circuits in which electricity is not being supplied (but are being charged) are shown by thin lines. Permanent line
A cutout switch and a temporary switch (not shown) are connected to L1 and the temporary line L1 ', respectively.

Here, it is assumed that the permanent line L1 is replaced. FIG. 4 (A) shows a normal operation state. When replacing with the permanent wire L1, the temporary wire L1 'is attached to the bushing B1 as shown in FIG. 4 (B) with the temporary switch opened. When the temporary switch is closed here, the permanent wire L1 and the temporary wire L1 'are energized in parallel as shown in FIG. 4 (C).

Next, open the cutout switch on the permanent line L1 and
As shown in FIG. 3D, the power is supplied only through the temporary line L1 '. After that, remove the permanent wire L1 as shown in Fig. 4 (E). Next, with the cutout switch open, install a new permanent wire L1 as shown in FIG. 4 (D), then close the cutout switch to connect the new permanent wire L1 and temporary wire L1 'in parallel to the fourth line. This is performed as shown in FIG.

Next, open the temporary switch and open the temporary wire as shown in Fig. 4 (B).
Stop the energization of L1 ', then remove the temporary wire L1'.

(A) → (B) → (C) → (D) shown in FIG.
→ (E) → (D) → (C) → (B) → (A) In all steps, the secondary side of the transformer continues to be energized. The process when the permanent wire L1 directly connected to the primary bushing B1 for the permanent wire is not replaced, such as when only the high-voltage side cutout switch is replaced, is (A) → (B) → (C) → in Fig. 4.
The process is (D) → (C) → (B) → (A).

As described above, even if the permanent line is cut off, the transformer can continue to operate without a momentary blackout.

In the present invention, the primary wire bushing for the permanent wire is attached to the side wall of the tank, and the primary bushing for the temporary wire is attached on the main cover. Is different. Therefore, the electric wires do not become congested in the work space, and the work of attaching and detaching the permanent wire and the temporary wire can be easily performed.

With the structure in which the temporary wire bushing is attached to the main cover as described above, the present invention can be easily applied to a conventional transformer.

Further, the transformer according to the present embodiment and the transformer having the conventional structure can be configured only by changing the main cover portion without changing the tank body and each part in the tank. for that reason,
The upper part of the tank has a branch connection (see FIG. 3).
(Corresponding to U1j, V1j, W1j) is provided, and it is preferable that the temporary lead primary bushing internal lead wire is connected and disconnected at this branch connection portion.

By the way, it goes without saying that it is desirable that the work of attaching and detaching the permanent wire and the temporary wire can be performed in a shorter time and more safely. As a bushing that serves these purposes, there is a plug type bushing.

FIGS. 5-8 show a bayonet type bushing suitable for use as a primary bushing.
This plug-in type bushing has a structure that can be separated into a transformer side bushing half portion 1 shown in FIG. 5 and an electric wire side bushing half portion 2 shown in FIG.

The transformer side bushing half 1 is temporarily placed in the state shown in FIG. 5 during the work, but it is not left for a long time in this state, and normally, the wire side bushing half 2 is inserted, Alternatively, the cap 3 is attached as shown in FIG.

The transformer-side bushing half 1 shown in FIG. 5 comprises a porcelain bushing 1a having a recess and a female contact 1b mounted in the recess of the porcelain bushing 1a. The female contact 1b has a tubular shape with a slit in the axial direction, and is made of a metal (phosphor bronze-based alloy) excellent in both conductivity and elasticity. The female contact 1b is connected to the connection fitting 1c fixed to the bottom of the recess of the porcelain bushing 1a.
Is connected to the primary winding through a wire (not shown).

The transformer side bushing half portion 1 is attached to the transformer tank Ta or the main cover Ca via a bushing packing Pa.

Plastic outer threaded ring 1d with outer thread engraved on the outer peripheral surface of the insulator 1a of the transformer bushing half 1
Is installed.

The electric wire side bushing half portion 2 shown in FIG. 6 is provided with a mold cone 2a, and a substantially columnar male contact 2b projects on the bottom side (the side opposite to the cone portion) of the mold cone. The base of the male contact 2b is embedded in the mold cone 2a.

A flange portion 2a1 is provided at an end of the mold cone 2a on the male contact side. The male contact 2b is connected to the permanent wire L1 or the temporary wire L1 'through the conductor portion in the mold cone.

The wire side bushing half 2 has a connecting ring 2c for fixing the transformer side bushing half 1 on the mold cone 2a.
Is rotatably attached to.

A flange portion 2c1 protruding in the inner diameter direction is provided at an end of the recess of the connection ring 2c opposite to the male contact. Mold cone in the hole 2c2 on the center side of the collar 2c1
2a is loosely fitted. The collar portion 2c1 of the connection ring is adapted to abut the collar portion 2a1 of the mold cone so that the connection ring 2c does not come out in the male contact direction of the mold cone 2a. An inner screw ring 2d made of plastic and having an inner screw threaded thereon is attached to the inner circumferential surface of the recess of the connection ring 2c in the axial direction. The inner threaded ring 2d is screwed onto the outer threaded ring 1d of the transformer side bushing half portion 1.

Wire side bushing half 2 and transformer side bushing half 1
Connection with male contact 2b to female contact 1b
This can be done simply by pushing in and screwing the inner screw ring 2d into the outer screw ring 1d and tightening.

The cap 3 shown in FIG. 8 is for covering the charging part of the transformer side bushing half 1 when the wire side bushing half 2 is not attached to the transformer side bushing half 1. The structure of the cap 3 corresponds to the connection ring 2d without the hole 2c2.

FIG. 7 shows a state in which the transformer side bushing half portion 1 and the electric wire side bushing half portion 2 are connected. Further, FIG. 8 shows a state in which the cap 3 is attached to the transformer side bushing half portion 1. The cap 3 is attached to the transformer-side bushing half 1 via a cap packing Pc.

Primary bushing for permanent wire during transport and storage of transformer
Both B1 and the temporary bushing primary bushing B1 'are in a state in which the cap 3 is attached as shown in FIG. During normal operation of the transformer, the permanent bushing primary bushing B1 is in the state shown in FIG. 7, and the transformer side bushing half of the temporary wiring primary bushing B1 'is in the state shown in FIG.

As described above, the plug-in type 1 shown in FIGS.
When the secondary bushing is applied to the primary bushing of the transformer shown in FIGS. 1 to 4, the permanent wire and the temporary wire can be attached and detached very easily and in a short time.

When performing the above-mentioned electric wire attachment / detachment work, the worker does not come into contact with the charging part at all, so that the safety of the work can be ensured and the mental burden on the worker can be reduced.

Also, as the primary bushing of the transformer, Figs.
If the plug-in type primary bushing as shown in the figure is used, the transformer will be in the capped state during transportation and storage, so the external dimensions of the transformer will be small, and the live parts will be damaged or contaminated. Is prevented.
Therefore, the transport cost and storage cost of the transformer can be reduced, and the deterioration of quality during transport and storage can be prevented.

In the above embodiment, the plug-in type bushing is applied to all the primary bushings, but the plug-in type bushing and the ordinary bushing (tightening type bushing, battledore terminal bushing, etc.) may be used together. For example, the plug-in type bushing may be applied to the temporary wire primary bushing, and the ordinary bushing may be applied to the permanent wire primary bushing.

In the above description, an example in which the present invention is applied to a pole transformer for three phases has been described. However, a pole transformer for single phase that is generally used, or a power distribution system installed on the ground or on the floor is used. It is needless to say that the present invention can be applied to a transformer for use as well.

[Effects of the Invention] As described above, according to the present invention, the primary bushing of the transformer is composed of the primary bushing for the permanent wire and the primary bushing for the temporary wire. The transformer can be operated uninterrupted by supplying electric power from the line.

Further, the primary wire bushing for the permanent wire is arranged on the side wall of the tank, and the primary bushing for the temporary wire is arranged on the main cover. There are advantages.

In particular, according to the second aspect of the invention, since the insertion type bushing is used as the primary bushing of the transformer, the work of attaching and detaching the electric wire can be performed safely in a short time.
For the primary bushing that uses the plug-in type bushing, remove half of the wire side bushing during transportation and storage.
Since the cap can be attached, the space occupied by the transformer during transportation and storage can be reduced, and damage to the primary bushing during transportation and storage and deterioration of quality can be prevented. There is.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is a first view.
FIG. 3 is a plan view of the drawing, FIG. 3 is a structural view showing a winding structure of the transformer of the present invention, and FIGS. 4 (A) to (E) are continuous transformers of the same embodiment. Fig. 5 is an explanatory view for explaining the process of replacing the permanent wire in the above condition, and Fig. 5 is a partial cutout of the transformer-side bushing half of the plug-in type bushing suitable for use as the primary bushing in the present invention. The front view shown in FIG. 6 is a front view in which a half of the electric wire side bushing of the bushing is partially cut away, and FIG.
The figure shows a front view of the transformer-side bushing half with the wire-side bushing half connected to it, and Fig. 8 shows the transformer-side bushing half with a cap attached. It is the front view shown. Ta ... Tank, Ca ... Main cover, B1, B1u, B1v, B1w ... Primary bushing for permanent wire, B1 ', B1u', B1v ', B1w' ... Primary bushing for temporary wire, B2, B2u , B2v, B2w, B2n ... Secondary bushing, 1 ... half of transformer side bushing of plug type bushing, 2 ... half of wire side bushing of plug type bushing, 3 ... cap.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeshi Nishimura 2-1-11 Tagawa, Yodogawa-ku, Osaka City, Osaka Prefecture Daihen Co., Ltd. (72) Tadashi Kuriyama 2-1-11, Tagawa, Yodogawa-ku, Osaka City, Osaka Prefecture No. Daihen Co., Ltd. (72) Creator Tetsuo Fujii 2-11-1, Tagawa, Yodogawa-ku, Osaka City, Osaka Prefecture Daihen Co., Ltd.

Claims (2)

[Scope of utility model registration request] 1. A distribution transformer in which a primary bushing and a secondary bushing are attached to a transformer tank whose upper end opening is closed by a main cover, wherein the primary bushing of each phase is a primary bushing for a permanent wire and The temporary wire primary bushing comprises two types of primary bushings, and the permanent wire primary bushing and the temporary wire primary bushing are commonly connected in a transformer tank and connected to a winding. A distribution transformer, wherein the primary bushing for a permanent wire is attached to a side wall portion of the transformer tank, and the primary bushing for a temporary wire is attached to the main cover. 2. The distribution transformer according to claim 1, wherein the primary bushing is a plug type bushing.