JPS5939010A - Lead wire of stationary electric induction apparatus - Google Patents

Abstract

PURPOSE:To facilitate assembling of an insulative barrier at connecting part and improve insulative strength, by a method wherein length between laps of a plurality of insulative barriers becomes smaller from electric connecting side to outside. CONSTITUTION:A lead wire taken from a transformer winding enclosed in a transformer tank 3, i.e. a first center conductor 29a is provided at end part with a connecting fitting 28a and at outer circumference with an inner electrode 30, an insulation coating layer 30a and a plurality of insulative barriers 26 arranged in concentric relation at prescribed distance. The plurality of insulative barriers 26 are so constituted that a first insulative barrier 26a at innermost layer is shorter than the inner electrode 30 by prescribed length and a second insulative barrier 26b is longer than the first insulative barrier 26a. The insulative barriers are varied in length stepwise in sequence. Insulative barriers 27 on outer circumference of a second center conductor 29b are also varied in length stepwise. Abutting lap dimensions l1-ln of the first and second insulation barriers become smaller from the innermost layer to the outermost layer.

Description

[Detailed Description of the Invention] The present invention relates to a static induction electric lead wire, and in particular, when transporting a large-capacity transformer to a site by rail or road, there are transportation restrictions due to weight, size, etc. At times, a method has been proposed in which the transformer is divided into parts and assembled on-site, that is, a transformer is transported in parts. One of these methods is to connect the transport unit transformer and the submerged sword A in parallel on-site, and an example of the case where two units are connected in parallel is shown in Fig. 1. The transportation unit transformers 1 and 2 each contain iron cores 5 and 6 and three parallel windings 7 in tanks 3 and 4, which are containers. may be two parallel. The high voltage windings of the windings 7 of these two transport unit transformers 1 and 2 are connected at the site through connection lead wires 8, sealed with ducts 9, and filled with insulating oil. The medium voltage winding wound concentrically with the high voltage winding is connected with a connecting glue lead wire 1o and housed in the duct 11, and the high voltage line end and the medium voltage line end are connected to the lead wire 12 and the lead wire. According to 13,
Bushing pockets 16 through ducts 14 and 15 respectively
．． 17.

In transformers assembled on-site in this way, the lead-
As shown by the circles in the figure, the connections of s, io, 12.13 include high voltage connections 18° 19.20 and 21 and medium voltage connections 22, 23° 24 and 25. Since there are many connection points, the working time in the atmosphere becomes long, and the winding 7 absorbs a lot of moisture, resulting in a decrease in the insulation 1#f strength. As a way to compensate for this drawback, conductors such as lead wires 8゜10, 12 and 13, that is, the center conductor (
8. A lead device that uses a contact method at the end of the second center conductor (second center conductor) to connect between the two. IQ, 12 and 13 are 500kV
Or, in the case of a 1000kV class transformer, it must be of a structure that can withstand that voltage.
Given the reduction in dimensions of 4 and 15, a multiple isolation barrier scheme is adopted.

This multiple insulating barrier system uses leads s, io.

A plurality of insulation barriers are arranged around the outer periphery of the insulation-coated second center conductor 12 and 13, respectively.
, 10. A continuous cylindrical insulating barrier cannot be arranged at the connection between the second central conductor of 12 and 13 and the first central conductor of the high-voltage winding or medium-voltage winding. Therefore, move the lead wires 8, 10 degrees 12 and 13, and
When connecting the center conductor and the first center conductor of a high-voltage winding or medium-voltage winding, a plurality of insulating barriers arranged around the outer periphery of both are lapped with each other, but the interval between the lap parts is If the creepage dielectric strength is small, the creeping dielectric strength will decrease, and if sufficient spacing is provided to prevent the creepage dielectric strength from decreasing, it will be difficult to fix the insulation barrier concentrically, and even a slight dimensional deviation will make it difficult to fit and assemble the insulation barrier. I won't be able to do it.

The present invention has been made in view of the above points, and an object of the present invention is to provide a static induction acid I-ide wire with an easy to assemble insulating barrier at a connection portion and good insulation rigidity.

That is, the present invention is characterized in that the inter-lap dimension of the plurality of insulating barriers gradually decreases from the electrical connection portion side toward the outside.

First, when assembling the insulation barrier at the connection,
We considered how to make assembly easier without reducing dielectric strength. In the so-called concentric electrode arrangement, the second and first central conductors of the lead wire and high/medium voltage winding are on the high voltage side, multiple insulation barriers are arranged concentrically around them, and the tank or duct is on the ground side. The electric field strength of the oil gap between the insulating barriers near the ground side is greater than the electric field strength of the oil gap between the insulating barriers near the ground side. Therefore, in a multiple insulation barrier structure in which the oil gaps between insulation barriers are arranged with equal sizes, the voltage applied to the oil gaps between each insulation barrier is different, and the voltage applied to the oil gaps is plotted on the vertical axis, and the voltage applied to the oil gaps between insulation barriers is plotted on the horizontal axis. The change characteristics of the voltage applied to the oil gap depending on the position of the oil gap between the insulation barriers are shown by taking the position of the gap. Inner layer voltage v
I is the highest, and the voltage V applied to the oil gap in the outermost layer is the lowest. The problem with multiple insulation barriers that have lapped parts due to butting or overlapping is creepage failure in the oil gap, that is, dielectric breakdown in the direction along the layer of the insulation barrier, but the lap parts of this insulation barrier can cause through-breakage. It also becomes a weak point as it progresses. Therefore, the dimension between the laps of the insulation barrier needs to be larger than the dimension that will cause creepage failure, but 1. As mentioned above, the voltage applied to the oil gap is higher on the inner layer side, and the voltage applied to the oil gap is lower on the outer layer side. Therefore, the dimension between the wraps of the insulation barrier should be larger toward the inner layer and smaller toward the outer layer.In this way, the insulation barrier can be assembled and adjusted while visually checking from the inside without reducing the dielectric strength. It has been confirmed that this facilitates the assembly of the insulating barrier at the connection. Therefore, in the present invention, the inter-lap dimension of the plurality of insulating barriers is made smaller as it goes outward from the electrical connection portion side.

This makes it possible to obtain lead wires.

Examples will be described below. One embodiment is shown in FIGS. 3 and 4. Note that parts that are the same as those in the conventional model are given the same reference numerals, and therefore their explanations will be omitted. In this implementation, the distance between the wraps of the insulating barrier with a number of faces of 26° and 27° is 1. ．． 1
1, 13, 1. t+ ') t2 > i so that it becomes smaller as it goes outward from the electrical connection part 28 side.
s > l n . In this way, the insulation barrier 26,
27 visual assembly adjustments are now possible,
At the connection part, that is, the lead conductor derived from the transformer winding housed in the transformer tank 3, that is, the first center conductor 2
9a has a connecting fitting 28a at its end, and an inner electrode 30, an insulating coating layer 3Qa, and a plurality of insulating barriers 26 on its outer periphery.
are arranged concentrically at a predetermined interval, and the plurality of insulating barriers 26 are such that the length of the first insulating barrier 26a, which is the innermost layer, is shorter than the inner peripheral electrode 30 by a predetermined length, and the second insulating barrier is 26b is configured to be longer than the first insulating barrier 26a. The next third insulation barrier 26C is the first insulation barrier 26a.
The fourth insulating barrier 26d is longer than the second insulating barrier 2.
6b, the fifth insulating barrier 26e is longer than the third insulating barrier 26C, the sixth insulating barrier 26f is shorter than the fourth insulating barrier 26d, and the seventh insulating barrier 26g is shorter than the fifth insulating barrier 26e. The lengths of the plurality of insulation barriers 26 are changed in a stepped manner so that the eighth insulation barrier 26h is longer than the sixth insulation barrier 26f.

The lead wire on the side to be moved so as to be connected to the first center conductor 29a of the transformer winding is a lead conductor provided with a connecting fitting 28b in the duct 9 coupled to the tank 3, that is, a second center conductor 29b, An inner circumferential electrode 31, an insulating coating tri3ia, and a plurality of insulating barriers 27 are arranged concentrically on the outer periphery.

The plurality of insulating barriers 27 have a first insulating barrier 27a serving as the innermost layer having a diameter comparable to that of the first insulating barrier 26a of the first central conductor 29a, and a length of the inner circumferential electrode 3.
The second insulating barrier 27b is shorter than the first insulating barrier 27a. The next third insulating barrier 27C is shorter than the first insulating barrier 27a, and the fourth insulating barrier 27C is shorter than the first insulating barrier 27a.
The insulation barrier 27d is longer than the second insulation barrier 27b, and the fifth insulation barrier 27e is shorter than the third insulation barrier 27c.
The sixth insulating barrier 27f is longer than the fourth insulating barrier 27d, the seventh insulating barrier 27g is shorter than the fifth insulating barrier 27e, and the eighth insulating barrier 27h is longer than the sixth insulating barrier 27f. Constructed by changing the length in a step-like manner.

Furthermore, the connecting fittings 28a of the first central conductor 29a and the connecting fittings 28b of the second central conductor 29b are made long enough to be pushed into the duct 9 when attached to the tank 3, and the first insulating barriers 26a of the plurality of insulating barriers 26 are connected to each other. and the diameter of the first insulating barrier 27a of the other plurality of insulating barriers 27 are approximately the same as described above, and the center conductor 29a, 29b is
When connected, each first insulating barrier 26' ar 2
7a are aligned so that the abutting portions of the second insulating barriers 26a and 27b of the husband and the husband and the predetermined barrier layers are in close contact with each other.

A first insulating barrier 26a is the innermost layer.

27a and the second insulating barrier 26b.

The length between the abutting portions of the third insulating barriers 26C and 27b, that is, the inter-lap dimension t1, the length t2 between the abutting portions of the third insulating barriers 26C and 27C and the abutting portions of the fourth insulating barriers 26d and 27d, and the fifth insulating barrier 26e127e. The length t5 between the abutting portion of and the abutting portion of the sixth insulating barriers 26f and 27f, the eighth insulating barrier 26h serving as the outermost layer,
Butt part of 27h and seventh insulating barrier 26g, 27g
The length tn between the abutting portions is 11>z2>za>l so that it becomes smaller from the innermost layer to the outermost layer.
It's n.

By doing this, when the second center conductor 29b is moved and fitted to the first center conductor 29aK, the plurality of insulating barriers 26, 27 are replaced by the first insulating barriers 26a, 27 of the innermost layer.
Since the abutting portions can be formed in order from a to the outermost eighth insulating barriers 26h and 27h, it is possible to visually check and adjust the misalignment of the abutting portions in order. ME $-ff 6fil'C! J“′
°·′″0 threat can facilitate 1. And the insulating barrier ゛26.27 has its lap dimension 11
. can do.

In this embodiment, the case where the plurality of insulating barriers 26 and 27 each have eight layers has been described, but the present invention is not limited to eight layers and can be applied to any number of layers.

Another embodiment of the invention is shown in FIG.

In this embodiment, a plurality of insulating barriers 26 and 27 are inserted alternately, and the overlapping length of the insulating barriers increases depending on the voltage applied to the oil gap between the insulating barriers, and increases toward the inner layer and increases toward the outer layer. Try to get smaller. By doing this, there is no abutting portion, so it becomes unnecessary to position the abutting portions of the insulating barriers 26 and 27, respectively, and manufacturing can be facilitated.

As mentioned above, the present invention wraps the insulating barriers together;
The wrap size is made smaller as it goes outward from the electrical connection side, so it is possible to maintain the desired dielectric strength and adjust the deviation by visually inspecting it from the inside, thereby improving the insulation barrier at the connection area. FIG. 4 is a longitudinal sectional side view showing the structure of the insulating barrier before it is assembled into the connection part, and FIG. 4 is a longitudinal sectional side view showing the structure of the insulating barrier after assembly of Example #1.

1.2...Transformer, 3,4...Tank (container), 2
6゜27...Multiple (multiple) insulation/rear, 28...
Electrical connection portion, 29a...first center conductor, 29b...
・Second center conductor, 30a, 31a...insulating coating layer, t
l.

t2, l-s, t-...Dimension between wraps.

-P)/Figure Ladle live bees ＼Riya between oil t ya standing l -

Claims (1)

[Claims] 1. A first center conductor and a second center conductor that are placed in a container filled with insulating oil and coated with insulation, and one of the second center conductor and the first center conductor is moved. a plurality of insulating barriers disposed around the electrical connection portion and the outer periphery of the rain center conductor and wrapped around each other when the rain center conductor is connected; In the lead wire for a stationary induction appliance having
A stationary induction electric lead wire that is characterized by being made smaller as the size increases.