JPH0296310A - Core type reactor - Google Patents

Abstract

PURPOSE:To reduce vibration and noise to nearly no vibration and noise level with a simple configuration by setting magnetic distortion of block core at a rated magnetic flux density in an expansion direction and cancelling it with an amount of contraction of a spacer due to magnetic attracting force. CONSTITUTION:A magnetic path is formed by a three-phase core leg 2 and a yoke 6 and a winding 1 is wound around each core length 2. The core leg 2 is made by piling up block cores 3 and spacers alternately and the block core 3 is set in a direction where the magnetic distortion is expanded. Thus, contraction of the spacer 4 due to magnetic attracting force operated between the block cores 3 can be compensated by expansion of magnetic distortion of the block core 3. It prevents structure to be simple, suppresses displacement of the iron leg as a whole, and reduces vibration and noise to nearly non- vibration and noise level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an iron core reactor, and more particularly to an iron core reactor with a gear lug, which has iron core legs constructed by alternately stacking block cores and spacers.

[Conventional technology] In recent years, as power transmission systems have become longer distances and underground cable systems have expanded in urban areas, the charging capacity of the grid has increased, and demand for shunt reactors to compensate for this has increased rapidly. is increasing.

This shunt reactor is required to have ultra-low noise specifications due to the environment in which it is installed, and reducing vibration and noise is the most important issue.

By the way, reactors are generally divided into air core type and iron core type, and although the former has excellent linearity of inductance,
Because the main magnetic flux passes through the winding, eddy current loss is large, and because a magnetic shield is provided surrounding the winding to form a magnetic path, the overall size becomes large.In contrast, the latter generally has a gap type. It is an iron core type, and because the number of turns of the winding can be reduced for the same reactance, it can be made smaller with low loss.

The geared iron core reactor has these advantages.
It is believed that vibration and noise are generated due to the magnetic attraction force of the gap portion, and this will be explained using the geared iron core reactor shown in FIG. 4(a) as an example.

The core legs 2A arranged inside each volume vA1 are made up of alternating cylindrical block cores 3A laminated with dark silicon steel plates 7A and non-magnetic cylindrical spacers 4 as shown in FIG. When stacked, a gap 5 corresponding to the height d of the cylindrical spacer 4 is formed between the plurality of cylindrical block cores 3A.

This type of geared core reactor is shown in the same figure (,).
When magnetic flux flows through the core leg 2A as shown in FIG. Induce the vibrations shown in the figure. Conventionally, as shown in Japanese Patent Application Laid-Open No. 58-131720,
By using a ceramic spacer or the like having a large Young's modulus as the spacer 4, the amount of shrinkage has been reduced and vibrations have been reduced.

[Problem to be solved by the invention] Conventional geared iron core reactors have used ceramic spacers with a large Young's modulus to reduce the amount of shrinkage in order to reduce vibration and noise, but this has its limitations. Satisfactory vibration/noise reduction effects were still not achieved.

An object of the present invention is to provide an iron core reactor that can reduce vibration and noise to almost no vibration or noise with a relatively simple configuration.

[Means for Solving the Problem] In order to achieve the above object, the inventors of the present invention have conducted various studies, and as a result of various studies, they have focused on the magnetostriction of the block core itself, whereas conventionally they focused only on the shrinkage of the spacer. However, when a contraction force is applied to the spacer, magnetostriction is caused in the block core in the elongation direction.In other words, the present invention has a core leg in which block cores and spacers are stacked alternately, and In an iron-core reactor in which a magnetic path is formed by a disposed yoke, the magnetostriction of the block core at the rated magnetic flux density is set in the elongation direction so as to offset the amount of contraction of the spacer due to the magnetic attraction force. Features.

[Function] Since the iron core reactor according to the present invention has the above-described configuration, even if the spacer contracts due to the magnetic attraction force acting between the block cores, this contraction is offset by the magnetostriction in the direction of extension of the block cores. Therefore, the displacement of the core leg as a whole can be suppressed without complicating the structure, and vibration and noise can be reduced to near zero vibration and noise.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1(a) is a front view showing an iron core three-phase reactor as an example of an iron core reactor.

A magnetic path is formed by the three-phase iron core leg 2 and the yoke 6,
A winding 1 is wound around each core leg 2. The structure of the iron core leg 2 is the same as the conventional one, in which block cores 3 and spacers 4 are stacked alternately, but the block core 3 is different in that its magnetostriction is set in the elongation direction. Such a block core 3 is obtained by removing a glass coating applied to a silicon steel plate that is usually reprinted.

As a result, the contraction curve y of the spacer 4 due to the magnetic attraction force f between the block cores 3 as shown in FIG. 1(c) is the same as the elongation curve will cancel each other out, and the overall displacement in the core leg 2 will be as shown by curve 2. In particular, the rated magnetic flux density generally employed in iron core reactors is 1.
It is in the range of 1 to 1.6 Tesla peak, and within this range, the block core 3 has its magnetostriction in the elongation direction. Therefore, the overall displacement in the core leg 2 becomes extremely small as shown by curve 2 within the range of the rated magnetic flux density, and vibration and noise can be significantly reduced. This can be well understood from FIGS. 6 and 7, which analyze a conventional iron core reactor from a similar viewpoint.

That is, as shown in FIG. 6, the magnetostriction acting on the block core 3A was in the range of the rated magnetic flux density of 1.1 to 1.6 Tesla peak, and was almost in the shrinking direction even considering the variation thereof. Therefore, as shown in FIG. 7, the amount of contraction δ2 of the spacer due to the magnetostriction m of the block core 3A is added to the amount of contraction δ of the spacer due to the magnetic attraction force f between the block cores 3A, and the displacement of the core leg as a whole is Σ( δ1+62).

FIG. 2 shows the magnetostrictive characteristics of the above-mentioned commercially available silicon steel sheet with a glass coating and silicon steel sheet from which the glass coating has been removed, in the range of rated magnetic flux density from 1.1 to 1.6 Teslabeak. It can be seen from the figure that by removing the glass film, the magnetostrictive properties of the silicon steel sheet can be changed from shrinkage to elongation. It can also be seen that when a compressive force is applied to a silicon steel plate, both become magnetostrictive in the elongation direction when magnetic flux passes through them.

FIG. 3 shows a part of a block core 3 made of a silicon steel plate that takes advantage of this latter characteristic. In this embodiment, molding is performed using a resin 8 that has a high shrinkage rate during curing, and the silicon steel plate 7 constituting the block core 3 is compressed using the compressive force during shrinkage. As can be seen from the magnetostrictive characteristic diagram in Figure 2, the compressive force at this time is preferably 20Kg/a# or more.The resin used is an epoxy resin with a high shrinkage rate, especially among epoxy resins that have high strength after curing. If an alicyclic system with a high This shrinkage rate is for novolac type.

Bisphenols, hydantoin epoxies, and alicyclics increase in order.

[Effects of the Invention] As explained above, in the present invention, since the magnetostriction of the block core is set in the elongation direction, the contraction of the spacer due to the magnetic attraction force acting between the block cores can be compensated for by the elongation due to the magnetostriction of the block core. Therefore, it is possible to obtain an iron core reactor that suppresses the displacement of the iron core legs as a whole without complicating the structure, and reduces vibration and noise to near zero vibration and noise.

[Brief explanation of drawings]

FIG. 1(a) is a front view of a core reactor according to an embodiment of the present invention, FIG. 1(b) is a displacement characteristic diagram of the entire core leg of FIG. 1(a), and FIG. 1(Q) is the same. FIG. 2 is a magnetostriction characteristic diagram of a silicon steel plate, FIG. 3 is a front view of a block core of an iron-core reactor according to another embodiment of the present invention, and FIG. ) is a front view of a conventional iron core reactor, FIG. 4(b) is an enlarged perspective view of the main part of FIG. 4(a), and FIG.
Figure (c) is an enlarged view of the main part of the core leg in Figure (a), Figure 5 is the vibration mode diagram, Figure 6 is the magnetostriction characteristic diagram of the conventional silicon steel plate, and Figure 7 is the conventional core leg. It is a vibration principle diagram. 1... Winding wire, 2... Core leg, 3...
...Block core, 4...Spacer, 7...
...Silicon steel plate, 8...Resin. Figure 1 Figure 2 Figure 3 Pressure Figure 4 Figure 5

Claims (4)

[Claims] 1. In an iron core reactor in which a magnetic path is formed by iron core legs in which block cores and spacers are stacked alternately and yokes placed above and below the iron core legs, the magnetostriction of the block core at the rated magnetic flux density is increased in the elongation direction. An iron core reactor characterized in that the amount of contraction of the spacer due to the magnetic attraction force is set to offset the amount of contraction of the spacer. 2. 2. The iron core reactor according to claim 1, wherein the rated magnetic flux density of the block core is set in a range of 1.1 to 1.6 Tesla peak. 3. 2. An iron core reactor according to claim 1, wherein said block core is made of a silicon steel plate without a glass coating. 4. 2. The iron-core reactor according to claim 1, wherein the block core is a silicon steel plate subjected to resin molding treatment so as to generate a compressive force of 20 kg/cm^2 or more.