JPS5947721A - Stationary induction apparatus - Google Patents

Abstract

PURPOSE:To suppress the concentration of electric field in a magnetic shielding member due to a lead wire from a winding and improve the attracting effect of the leakage flux from the winding by the magnetic shielding member by providing a notch whose shape follows the shape of the lead wire to the magnetic shielding member at the part facing the lead wire. CONSTITUTION:A magnetic shielding plate 20 is uniformly notched along the shape of a lead wire 11 from an internal winding at the part facing the lead wire and near the center of the phase (C-C). The region of the notched part 21 does not cut the magnetic path in the magnetic shielding plate 20 which covers all three-phase windings and the path of the leakage flux which flows longitudinally in the magnetic shielding plate 20 is secured. With this constitution, the concentration of the electric field to the lead wire from the internal winding is suppressed without enlarging the distance between the magnetic shielding plate 20 and the winding.

Description

[Detailed Description of the Invention] The present invention relates to stationary induction electric appliances such as transformers and accelerators.
In particular, it relates to a magnetic shield for controlling leakage magnetic flux from windings.

In recent years, the capacity of stationary induction electric devices such as transformers has been increasing, and leakage flux from the windings has also increased. , reduction of generated loss is seen as a problem from the viewpoint of performance and durability 1. Fasteners for transformers are an example of this.

This will be explained with reference to the internal structure diagrams of a conventional transformer shown in FIG. J and FIG. 2. The iron core is constructed by combining the U leg part 3 and the yoke part 4. It is tightened. The core yoke parts 4 and 5 are arranged on the tote of the core leg part 3, and core clamping fittings 6 and 7 are applied to both sides of the core yoke parts 4 and 5 to tighten them. This clamping fitting 6°7 tightens the core yoke parts 4 and 5, and also the inner winding 1 and the outer winding +li! wound around the core leg part 3! i! Conventionally, in a transformer having a structure such as 1 or 2, which also has the effect of pressing the magnetic flux 2', a considerable amount of the magnetic flux leaking from the windings as shown by the arrow in Fig. 1 is completely absorbed. A magnetic shielding plate 8゜9 with high magnetic permeability is provided on the winding side surface of the upper core clamping bracket 6 and the bottom core clamping bracket 7, and leakage is absorbed by the magnetic shielding plates 8 and 9. It acts to guide magnetic flux in a direction perpendicular to the plane of the paper where magnetic resistance is low.

The properties of the leakage magnetic flux attracted by such a magnetic shield plate can be expressed as 3, consisting of U, V, and W phases, as shown in Figure 2 (a).
Looking at the phase transformer, leakage magnetic flux from each phase is φ8. φ7
．． φ7 has a phase difference of 120 degrees and exhibits vectorial Nihalance, resulting in a flow in which most of the leakage magnetic flux is confined within the magnetic shield plate. Furthermore, if we look at the shape of the magnetic flux distribution flowing in the longitudinal direction in this magnetic shield plate, we can see that (in Figure 2)
U as shown in K.

It also has the characteristic that it accumulates and reaches a peak value near the winding correlation portions of the V phase, ■, and W phases.

The magnetic flux attracting effect of such a magnetic shield plate can generally be improved by placing it as close as possible to the windings 1 and 2, which are the sources of leakage magnetic flux, but this is inevitably limited in terms of insulation performance.

Particularly, the hatched part A in FIG. 1, that is, the outer end of the magnetic shielding plate close to the lead wire 11 from the inner winding, and the hatched part B in FIG. 2, that is, each phase. A problem arises in that the electric field is significantly concentrated near the center fC-C), making it easy for discharge to occur.

Therefore, in order to prevent electric field concentration from the force side winding to the lead wire 11, thick wires must be placed between the magnetic shield plates 8 to 9 and the windings 1 and 2. However, the shape of the transformer inevitably becomes larger, and the magnetic flux attraction effect of the magnetic shield plate also decreases.

The purpose of the present invention is 1 to eliminate the above-mentioned drawbacks of the prior art;
To provide a stationary induction electric appliance which can prevent electric field concentration in a magnetic shield member in the vicinity opposite to a lead wire from a winding, and can sufficiently generate the magnetic flux attracting effect of the magnetic shield member.

In order to achieve all of these objects, the present invention is characterized in that a notch portion that substantially follows the shape of the lead wire is provided in a portion of the magnetic shielding member that faces the lead wire.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with respect to each of the illustrated embodiments.

FIG. 3 is an embodiment of the present invention, and is a top front view of a three-phase transformer showing the same portion as FIG. 2. In the figure, the same reference numerals as in FIG. 2 indicate the same parts.

This embodiment differs from conventional transformers in that the magnetic shield plate 20 is aligned along the shape of the lead wire near the phase center <C-C> facing the lead wire 11 from the inner winding. It is a point that is notched like this.

Moreover, since the range of the notch 21 of the magnetic shield plate 2o does not block the magnetic path of the magnetic shield plate extending over the three-phase winding, the path of leakage magnetic flux flowing in the longitudinal direction in the magnetic shield is ensured. There is.

According to this structure, it is possible to prevent electric field concentration from the inner winding to the lead wire without increasing the distance between the magnetic shield plate 20 and the winding, so that the above-mentioned problem that occurs with the conventional magnetic shield plate can be prevented. Many of these shortcomings can be improved.

Since most of the notches 21 are normally located at the center of the phase, the amount of magnetic flux flowing through the magnetic shield plate is also small, as is clear from FIG. 2(b). Therefore, even if such a notch 21 is provided, the magnetic flux density in the magnetic shield plate is rather made uniform, and the magnetic flux attraction effect is not hindered at all.

FIG. 4 to FIG. 8 t show other embodiments of the present invention. The arrangement is such that the magnetic flux attracting effect of the magnetic shield plate 2o described in the embodiment shown in the figure can be further enhanced.

FIG. 4 shows the shape of the notch 31 of the magnetic shield plate 3o.
T like the embodiment in Figure 3? Z aThe wires 11 are drawn out from the inner winding without being uniform in the width direction of the heat shield plate.
It is formed in an L shape that roughly follows the shape in the height direction.
In the 21-wire structure in which the magnetic shield plate 30 is closer to the winding than the magnetic shield plate 20 shown in FIG. , is the magnetic shielding plate 3o the winding thread at the inner side of the winding, which is usually the largest? 1°2, the effect of attracting leakage magnetic flux by the magnetic sheet plate 30 is only further promoted, and the effect and action of preventing electric field concentration on the lead wire 11 is secondary. This is no different from the example shown in FIG. 3. In order to facilitate the production of the magnetic shield plate 30 shown in FIG. 4, FIG.
1! Figure 6 shows an example in which the magnetic shield plates are divided into magnetic shield plates 'e50,5], 52 in the radial direction.

Furthermore, Fig. 7 shows an example in which the magnetic shield plates are divided into 60 to 63 in the height direction and radial direction, and Fig. 8 shows the iron core tightening bracket 6.
This is an example in which the magnetic shield plate 70 is installed to show the entire structure when the magnetic shield plate 70 is composed of a single flat plate, but in any case, both the electric field relaxation effect and the magnetic flux attraction effect are the same as those shown in Figs. 3 and 4. There is essentially no difference.

As explained above, according to the present invention, it is possible not only to effectively suppress electric field concentration in the magnetic shielding member caused by lead wires from the winding, but also to reduce magnetic flux leakage from the winding due to the magnetic shielding member. The suction effect can be further improved.

[Brief explanation of the drawing]

Figure 1 is an internal vertical sectional view of a conventional transformer, Figure 2 (a)
, (b) is a top side view of the transformer and a magnetic flux distribution diagram of the magnetic shield plate, FIG. 3 is a top side view of the transformer according to an embodiment of the present invention, and 4th fr21~! +; Figure 8 is a vertical sectional view of the main part of a transformer according to another nominal shelf side of the present invention. 1.2... Inner and row side winding; 1... Iron core legs;
4゜5...Iron core yoke part, 11...Jil, wire,
zo, :3o. 40 to 42.50 to 52.60・63.70...Magnetic shield plate, 21,3]...Notch part. Figure 1 Figure 2 (0-) Cb) yFJ5 Figure 6 Figure 7 Mouth shoulder 8 Figure white l 2

Claims (1)

[Claims] 1. A plurality of core legs, and core yoke parts disposed at both ends of these core legs to fully magnetically couple the core legs;
The iron core leg includes a winding that is wrapped around the core leg, and a magnetic shielding member that is provided at the upper and lower ends of the winding between the windings having different phases. The winding is drawn outward in the radial direction through a gap with the magnetic shielding member (7).
A stationary induction electric appliance characterized in that a cutout portion that substantially follows the shape of the lead wire is provided in a portion facing the lead wire.