JPS6037706A - Transformer with no-voltage tap changer - Google Patents

Abstract

PURPOSE:To improve a winding space factor as well as to reduce manhour in order to miniaturize a transformer, by dividing a tap winding into rough and fine sections which are respectively provided at the both ends and the intermediate position of a high-voltage winding. CONSTITUTION:A tap winding is divided into a fine winding section 6 having a plurality of taps in which a tap delivery is drawn out from each tap having a voltage (e), and into rough tap winding sections 7-1 and 7-2 having a plurality of taps in which a tap delivery is drawn out from each tap having a voltage (2e). The winding sections 7-1 and 7-2 are provided on the both ends of a high- voltage winding 3A, 3B while the delivery thereof is connected to the neutral point N through a tap changer. The winding section 6 is provided at the intermediate position of the winding 3A, 3B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in the tap extraction structure of a transformer having a voltageless tap changer.

[Technical Background of the Invention and Problems Therewith] Normally, a transformer is provided with a tap, but when there is no need to constantly change the tap voltage, a non-voltage tap switching system is generally used. FIG. 1 shows a winding structure in which five non-voltage taps are provided in the high-voltage winding of a conventional transformer with a non-voltage tap changer. Concentrically on the core leg (1), there is a low voltage winding (2) from the inside, and a high voltage winding on the outside above and below; gland (3)
Wrap it around. In FIG. IC, a line terminal U is provided approximately at the center of the high voltage winding (3) in the vertical direction, that is, in the stack direction. The high-voltage winding (3) is wound asymmetrically around the line terminal U.

High voltage winding (3 is the high voltage main winding (3-1), (:3~2)
and tap winding, (c) and Karanashi, high voltage winding (3)
A neutral point N is provided at each end of the line, and a gap is formed approximately in the center between the neutral point N and the line terminal U to connect the oil pipe section g.
.

(hereinafter referred to as free g.) is provided.This grease g
Tap windings (4σ, (4no) are provided on both sides so as to sandwich o. Also, tap openings (41) are provided on both sides of the tap winding (41).
, and tap windings (for the bone, draw out tap openings ■ to ■. Then, voltage 4e between ■ and ■, voltage 3e between ■ and ■, voltage 2e between ■ and 0, voltage e between ■ and 0, voltage O between ■ and 0, and the voltageless tap changer is activated. short-circuited by the contactor (8) and 5 as described above.
The voltage of the tap can be changed.

In such a conventional tap winding structure, for example, in the case of the lowest tap where tap leads ■ and ■ are connected, the tap windings connected to tap leads ■ and ■ are in a potential floating state, so line terminal U 7 ) When a lightning impulse invades, a high oscillating voltage is generated between the tap openings (4+) and (3) due to the potential oscillation within the tap winding, and the electrical voltage applied between the tap windings (4+) and (c) is generated. Stress increases. Due to this high electrical stress, the winding +41)
, +4; The aforementioned brief g formed during 1. It is necessary to widen the gap of brief go to prevent K dielectric breakdown.

On the other hand, for the high voltage winding <37, the axial ampere turn distribution changes depending on each tap, so the tap winding (tυ) of the high voltage winding (3) and the diagonal line of the low voltage winding (2) opposite to (4) are applied. It is necessary to reduce the degree of ampere-turn unbalance between the high and low voltage windings by reducing the ampere-turns in terms of the axial unit length and shortness of the winding portion (2a).

In other words, in Figure 2(a), the vertical axis has a hook with a winding height of 9.
゜If we take the ampere turn (q6) on the horizontal axis, we will find the highest tap H of the high voltage winding (indicated by the two-dot chain line), the lowest tap L of the high voltage winding (indicated by the broken line), and the low voltage winding LT (indicated by the solid line). ) shows a diagram of the axial ampere-turn distribution. Thus, the unbalance of the axial ampere turns generates magnetic flux in the vicinity of the tap winding in a radial direction, that is, in a direction perpendicular to the winding axis. As a result, the axial mechanical force increases, and the stray loss generated inside the winding conductor, the tank, the core contact plate, etc. increases.

If it is necessary to widen the tap range due to system requirements, if the tap winding (4n, If the difference in ampere turns is plotted on the horizontal axis, the difference in magnetomotive force distribution will be as shown between the highest tap H (indicated by a two-dot chain line) and the lowest tap L (indicated by a broken line). High like this,
The ampere-turn magnetomotive force difference between the low-voltage windings becomes too large, and the axial mechanical force becomes very large. To deal with this, we increased the conductor cross-sectional area), increased the thickness of the winding clamping plates placed above and below the windings, and used a high-strength material for the core contact plates. Not only does the transformer become larger, but it also becomes more expensive. Of course, the radial magnetic flux increases and the stray loss also increases.

Furthermore, when a lightning surge or shock voltage enters, the total voltage between taps may exceed the allowable value of a large switch.

To avoid this, there is a method of dividing and arranging the tap winding. An example of this is shown in FIG. In the figure, j, -1-/
# n= 孭'in IQI ty'i dr I for I
r 9 m Weθ)go I+ 7 σ.

g2, and the first and second tap winding portions (4-1) sandwiching each brief g+2g2, (
4-2) is formed. The first tap winding part (4-1) is connected to the tap winding (c) by sandwiching the block IJ-ring g2 at each end of the high voltage main windings (3-3) and (3-4). ,(4
Set up Q. Further, the second tap winding section (4-2) holds the brief g2 between the high voltage main windings (3-4) and (3).
-5) at each end of the tapped winding (47), (
48) 'ff: Provided.

The tap winding of the first tap winding section (4-1) (44 has tap openings ■, ■, ■, still tap winding (former tap openings ■, ■, ■), tap changer A movable contact αυ is provided.

Also, the tap winding (47) of the second tap winding section (4-2)
) for tap openings ■, ■, ■, and tap windings (4S
Tap outlets ■, ■, ■ are provided, and a movable contact (la) of the tap changer is provided.The tap voltage between each tap is formed to be voltage e]L.Then, the tap voltage due to the tap changer is As shown in FIG. 4, each energizing tap voltage can be obtained by connecting the tap leads, and 7 of 8 steps (so-called 9p) can output pressure.

This tap range is ±4e based on the current tap instruction ■
(9p).

The degree of axial ampere-turn unbalance between the high and low voltage windings due to the first tap winding section (4-z) having brief g+ is determined by the tap configuration shown in FIG. It can be made almost equivalent to the case of ±2e (5p). That is, since each peak of the highest tap H and lowest tap L shown in FIG. 2(b) is divided into two, it becomes similar to FIG. There is no such thing.

Also, the degree of ampere-turn unbalance due to the tap winding (4-2) with brief g2 is also the same, with ±4e at one location.
Because the degree of ampere-turn unbalance can be made smaller than when arranging tap windings.

In other words, by arranging the tap winding in two parts in the high-voltage winding, even if the tap range is widened, the increase in axial short-circuit mechanical force will not be large, and it will not occur in the winding conductor or tank. It is also possible to suppress the degree of increase in stray loss.

On the other hand, when a lightning impulse invades, the voltage applied to one tap changer is reduced to about 1/2 since the tap winding is divided into two parts, and a small tap changer can be used. Put it away.

However, in the tap winding configuration as shown in Fig. 3, the first and second tap winding sections (4-1) and (4-2) require briefs g□e gz, respectively, and a lot of extra space is required. There was a problem that needed to be improved, as it required 12 tap openings, which increased the number of man-hours.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and its purpose is to avoid increasing the axial short-circuit mechanical force even if the tap range is widened, and to increase the stray loss generated in the structural members. To provide a transformer with a non-voltage tap changer, which can reduce the number of brief points, reduce the number of taps, and reduce the number of taps.

[Summary of the invention]

In order to achieve such an object, the present invention includes winding a low-voltage winding around the core leg from the inside, winding a high-voltage winding thereon, and winding the high-voltage winding symmetrically on both sides from the center of the winding. It is equipped with a high-voltage main winding and a tap winding, and one tap winding.
a close tap winding section having a plurality of taps with a tap outlet for each tap having a voltage of at least 2e;

The coarse tap winding section is arranged at both ends of the high voltage winding, and the coarse tap winding section is arranged at both ends of the high voltage winding. The tap outlet of the wire is connected to the neutral point through the tap changer, and the close tap winding section is placed in the middle of the high voltage main winding, increasing the axial short circuit mechanical force even if the tap range is widened. Seven things to do! It will be on standby.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a transformer with a no-voltage tap changer according to the present invention will be described below with reference to the drawings. The same parts as in FIGS. 1 to 3 are designated by the same reference numerals. The high-voltage winding (3) is placed on top of the high-voltage winding (3), which is wound vertically symmetrically from among the windings. A line terminal U is provided approximately in the center of the high voltage winding (3).

In the illustration, the lower half of the line terminal U will be explained. The high-voltage winding (3) is provided with an oil passage section with a gap formed in the middle, a so-called brief g.

A dense tap winding portion (6) consisting of tap windings 60) and <51) is formed at the ends of the high voltage main windings (3A) and (3B) that sandwich this brief g, and the high voltage main winding (3B)
On the opposite side of the brief g, that is, on the neutral point side, a rough tap winding portion (7-w) consisting of a tap winding (branch) is arranged.

Tap winding of close tap winding part (6) (5G, 5])
, the tap openings are drawn out for each etap voltage e, tap openings ■, ■, ■ are provided on the tap winding 6G, tap openings ■, ■, ■ are provided on the tap winding 6D, and the movable contact of the tap changer is A close tap winding section (6) is constructed by providing a coil.

In addition, the six tap windings of the high-voltage main winding (3B) are formed with tap openings ■, ■, and ■ for every tap' pressure forming 2e. A similar rough tap winding part (7-z) is formed in the coil, tap openings ■, ■, and ■ are provided in the same manner, and a voltage-free tap switching is performed to switch and contact these tap openings ■, ■, and ■. The movable contacts aω of the device are collectively connected to the neutral point N to form coarse tap windings (7-1) and (7-2).In this way, the fine tap windings (6) and coarse tap windings Tap winding part (7-1),
(7-2) is not arranged continuously, but is arranged via a part of the high voltage main winding.

The length of the high voltage winding (3) in the axial direction with respect to the low voltage winding (2), that is, the stack length is the coarse tap winding portion (7).
-1) and (7-2) are each about one tap long.

Next, the effects of the uninvented embodiment will be explained in detail.

By operating the voltageless tap changer, the taps are connected to the fine tap winding section (6) and the coarse tap winding section (''-t) + (7-2) according to the tap instruction as shown in Fig. 6. Correspondingly, the energizing tap voltage is 8 from voltage 8e to voltage O.
The voltage of step (9p) can be switched.

In the embodiment of the present invention, the number of briefs between the tap windings is reduced from two in the conventional FIG. 3 to one, thereby improving the space factor of the windings.

Furthermore, the number of taps is reduced from 12 in the conventional method shown in FIG. 3 to 9, and the number of man-hours can be reduced.

In addition, since the coarse tap winding parts (7-1) and (7-2) are on the neutral point side, in the case of stage insulated windings, there is no ground insulation between the tap changer on the coarse tap winding side and the tank, etc. It has the advantage of requiring less distance. In this way, it is useful for downsizing the transformer and reducing the man-hours required for tapping the taps.

On the other hand, since the coarse tap winding parts (7-1) and (7-2) are arranged at the ends of the high voltage windings, the unbalanced ratio of ampere turns between the high and low voltage windings increases in these parts. However, since the axial mechanical force is generally maximum at the lowest tap at ttj, that is, at the tangent αN, 2) Since the winding is sterile, the height of the low voltage winding (2) is approximately equal to the height of the high voltage winding at the lowest tap. Therefore, the proportion of unbalanced ampere turns between the high and low voltage windings is reduced.

However, measures have been taken to reduce the ampere turns per unit length at the ends of the low voltage winding (2) where the coarse tap windings (7-1) and (7-2) are facing each other. , the proportion of unbalanced ampere turns between the low voltage windings can be reduced. In other words, the tap winding (,
17)', (Reducing the ampere turn/height of the shaded portion (2a) of the low voltage winding opposite to 41 has the same effect as making the so-called ampere turn thinner.

In this way, the space factor of the winding does not decrease compared to the conventional winding configuration shown in FIG.
Compared to the conventional configuration shown in the figure, it can be made smaller by l''.

Next, an example of a song according to the present invention will be described. In the embodiment of the invention shown in FIG.
, the tap winding portions (7-1) and (7-x) each receive tap 4 voltage equal to the voltage 4e, but for example, by changing this ratio, the dense tap winding portion (6) receives a tap voltage of 6e. The same effect can be obtained even if the voltage 2e is shared between the rough tap winding parts (7-1) and (7-2). Also, depending on the number of tap points, the same effect can be obtained by setting the tap winding lead voltage to an integer multiple of two or more logics, for example, about 2 to 4 times, of the close tap winding lead voltage e.

[Effects of the Invention] As explained above, according to the embodiments of the present invention, the number of tap openings is small in order to obtain the same number of taps, and the tap windings provided between the tap windings ( Since it floats, it has the advantage that fewer oil pipes, or briefs, are required to be spread out more than the general part of the vessel to maintain this insulation.

In addition, since the tap winding is divided into two parts, even if the tap range is widened, the mechanical force in the winding 1ifi11 direction will not become excessive in the event of a short circuit, and in the case of stage insulation, the tap connected to the neutral point side will not The switching device's d pressure to the ground is also low.

In this way, it is possible to provide a compact transformer with a single-voltage tap changer that improves the winding space factor and requires less man-hours.

[Brief explanation of drawings]

Figure 1 is a cross-sectional explanatory diagram of the winding configuration of a conventional transformer with a no-voltage tap changer, and Figures 2 (a) and (b) show the axial ampere-turn distribution and magnetomotive force distribution of Figure 1, respectively. 3 is a cross-sectional explanatory diagram of the conventional winding configuration when the tap range is wide, FIG. 4 is a drawing of the connection characteristics of the tap lead in FIG. 3, and FIG. 5 is a diagram of the voltage-free tap switching according to the present invention. FIG. 6 is a cross-sectional explanatory diagram of the winding structure of the transformer, and FIG. 6 is a diagram showing the connection characteristics of the tap outlet in FIG. (1) Core leg (2) Low voltage winding (3) High voltage winding (3A), (:(B) High voltage main winding (6) Close tap winding section (7-1), (7-2) ) Coarse tap winding part U-/line terminal N Neutral point terminal u, v Low voltage winding terminal g Oil road capital (brief) agent Patent attorney Inoue - Male No. 1 Figure 3 Figure 4 Figure 3 Figure 4 Figure 3 Beg ゛ ㅅしl■■ ■, @8e I ■■ ■, @7C F■, ■ ■, ■ge ■■7■ ■■ 5e ■■2■ ■7■ 〃e ■7■ ■, o3e Cao's , ■ ■02e ■'s ω, ○ /e

Claims (1)

[Claims] A low-voltage winding is wound on the core leg, and a high-voltage winding is wound on the outside of the core leg, and this high-voltage winding is wound symmetrically with respect to the center, and a high-voltage main winding and a tap winding are connected. In the transformer with a no-voltage tap changer, the tap winding includes a close tap winding portion having a plurality of taps each having a tap with a voltage e, and a close tap winding portion having a tap with a voltage of at least 2e. Each tap is divided into a coarse tap winding portion having a plurality of taps, and this rough tap winding portion is disposed at both ends of the high voltage winding, and the coarse tap winding portion is 1. A transformer with a no-voltage tap changer, characterized in that an outlet is connected to a neutral point through a tap changer, and the close tap winding portion is disposed at an intermediate position of the high voltage main winding.