JPH03245748A - Air gap armature winding - Google Patents

Abstract

PURPOSE:To prevent an insulting reliability from decreasing without increasing the thickness of a main insulator by interposing a charging space having a sufficiently large corner between a double dislocation conductor and the insulator, and further forming an equipotential surface covering the periphery with a semiconductive member. CONSTITUTION:A double dislocation conductor 1 is formed by bundling strands 3, twisting them to compress primary twisted wire 2 in a rectangular shape. A charging spacer (insulating spacer) 4 having a sufficiently large corner as compared with the corner of the conductor 1 is inserted between the conductor 1 and a main insulating layer 7, the periphery is covered with a semiconductive member 6 to form an equipotential surface. When the equipotential surface is disposed, it becomes equal potential to the conductor 1 to form an equipotential surface along the corner of the spacer 4 disposed at the corner of the conductor. Accordingly, the conductor angle can be substantially increased. Therefore, the concentration of the electric field at the corner of the conductor is alleviated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to improving the insulation reliability of a gap armature winding mainly used in a stator armature winding of a superconducting generator.

(Prior art) The stator armature winding of a conventional normal conduction generator is placed in a slot in the iron core, and the armature winding consists of rectangular copper wires arranged in a rectangular shape and a mica conductor with transposed armature conductors.・Those with main insulation made of a glass tape layer hardened with resin are generally used.

(Problems to be Solved by the Invention) On the other hand, in the stator of a superconducting generator, the magnetic flux density is large, and if the stator of a conventional normal-conducting generator has an iron core slot structure, the iron core teeth between the slots An air-gap armature winding structure is adopted because the magnetic flux density reaches the saturation region and causes overheating.

The air-gap armature winding structure is one in which a slot is formed of an insulator and the armature winding is arranged within the slot.

In the conventional iron core slot method, the field magnetic flux passes through the iron core teeth, so the influence of the field magnetic flux on the armature conductor in the slot is small. However, in the case of an air-gap armature winding structure, the armature conductor within the insulator slot also becomes a magnetic path and is directly affected by the alternating magnetic field of the strong rotating field. In order to reduce the eddy current loss induced in the armature conductor by an alternating magnetic field, a double dislocation conductor is used in the armature conductor of the air-gap armature winding structure.

A double dislocation conductor is usually made by bundling and twisting strands (copper wires) with a diameter of about 1 mm, compressing them into rectangular shapes, arranging the primary strands in a rectangular shape, and then twisting between the primary strands to eliminate dislocations. That's what I did.

The air-gap armature winding consists of double transposed conductors 1 as shown in FIG.
A main insulation 7 made of a mica/glass tape layer hardened with resin is applied around the main insulation 7.

Here, we will focus on the insulation reliability of the air-gap armature winding main insulation. Electric field stress is applied to the main insulating layer in response to the voltage induced in the armature conductor, and stress generally increases at the corners of the conductor due to electric field concentration.

For the average stress of the main insulation layer. The ratio of maximum stress due to electric field concentration at the corner of the conductor is as shown in FIG. That is, for the same main insulation thickness, if the corner radius of the conductor corner is small, the maximum stress due to electric field concentration will increase, leading to a decrease in insulation reliability. In the case of a conventional armature winding, the conductor angle R corresponds to the angle R (about ion) of a rectangular copper wire, whereas in the case of an air-gap armature winding, it corresponds to a diameter of 1 m constituting the −th order stranded wire.
This corresponds to the angle R of the strands of about 0.5 mm or less (about 0.5 mm or less).

Therefore, in the air-gap armature winding, electric field concentration at the corners of the conductor is large, leading to a decrease in insulation reliability.

An object of the present invention is to ensure a large conductor angle R in an air-gap armature winding to alleviate electric field concentration at the corners of the conductor, and to prevent a decrease in insulation reliability without increasing the main insulation thickness.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, in the present invention, primary stranded wires made by bundling thin conductive wires, twisting them and forming them into a rectangular shape are arranged in a rectangular shape, and the primary strands are further twisted between the primary stranded wires. In an air-gap armature winding formed by applying main insulation to a double-transposed conductor that has undergone translocation, there is a corner between the double-transposed conductor and the main insulation that is sufficiently larger than the corner of the double-transposed conductor. A filling spacer is inserted and formed, and a corner portion sufficiently larger than the semiconductive corner portion is formed around the filled spacer. Further, the above object can also be achieved by interposing a semiconductive filling spacer having a corner portion sufficiently larger than the corner portion of the double dislocation conductor between the double dislocation conductor and the main insulation.

(Function) The present invention is configured as described above, and when equipotential surfaces are not arranged in the air-gap armature winding, the angle R (0, 5 m or less) becomes the conductor angle R. However, when an equipotential surface is placed, the equipotential surface has the same potential as the double dislocation conductor, and the equipotential surface is placed along the corner R of the insulating spacer placed at the corner of the conductor. Therefore, it is possible to substantially secure a large conductor angle R. Therefore, electric field concentration at the corners of the conductor is alleviated, and a decrease in insulation reliability can be prevented.

(Example) An embodiment of the present invention will be described with reference to FIG.

The double transposed conductor 1 is a strand 3 (formal copper wire) with a diameter of 1
Several dozen primary strands 2 are bundled together, twisted and compressed to form a rectangular shape, and are arranged in a rectangular shape, and the primary strands are further twisted to perform transposition.

Insulating spacers 4 are arranged on the upper and lower surfaces of the double dislocation conductor 1. Filled mica or the like is used for the insulating spacer 4.

The corner radius of the insulating spacer is approximately 21111 mm.

Further, the double dislocation conductor 1 and the insulating spacer 4 are wrapped and surrounded by a semiconductive member layer 6 made of a semiconductive tape or sheet.

On top of that, main insulation is applied, which is a mica/glass tape layer 7 hardened with a resin such as epoxy.

In this embodiment, since the angle R of the insulating spacer is set to about 21, an equipotential surface is formed along this angle, so that the conductor angle R with respect to the main insulating layer is about 2-. Assuming that the main insulation thickness is 5 m, the graph in FIG. 3 shows that the ratio of the maximum stress to the average stress at the corner of the conductor is about 1.8.

On the other hand, in the conventional configuration, the conductor angle R is 0.5 mm in radius of the wire.
5m+, and if the main insulation thickness is the same <5W11,
From the graph of FIG. 3, the ratio of the maximum stress at the corner of the conductor to the average stress is about 2.9.

Next, another embodiment will be described using FIG. 2.

A semiconductive spacer 5 made of filled mica containing carbon or the like is arranged on the upper and lower surfaces of a double dislocation conductor 1 configured in the same manner as shown in FIG.
Processed to about +w++. On top of that is applied a layer of mass strength/glass tape hardened with a resin such as epoxy.

In this case as well, the semiconductive spacer has the same potential as the double dislocation conductor, and the conductor angle R with respect to the main insulating layer is about 2 m.

〔Effect of the invention〕

As described above, according to the present invention, electric field concentration at the corners of the conductor on the main insulating layer of the air gap armature winding is alleviated, and deterioration in insulation reliability can be prevented without increasing the main insulation thickness.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part of an air-gap armature winding according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a main part of an air-gap armature winding according to another embodiment, and FIG. 3 is a conductor angle FIG. 4 is a cross-sectional view of a main part of a conventional air-gap armature winding.

Claims (2)

[Claims] (1) A void formed by arranging primary stranded wires made by bundling thin conductive wires, twisting them and compressing them into a rectangular shape, and applying main insulation to a double transposed conductor which is further twisted between the primary stranded wires to perform dislocation. In the armature winding, a filling spacer having a corner that is sufficiently larger than the corner of the double transposition conductor is inserted and formed between the double transposition conductor and the main insulation, and a semiconductive member is further formed around the spacer. An air-gap armature winding characterized by being covered with an equipotential surface to form an equipotential surface. (2) A void formed by arranging primary stranded wires made by bundling thin conductive wires, twisting them and compressing them into a rectangular shape, and applying main insulation to a double-translocated conductor in which the primary strands are further twisted and transposed between the primary stranded wires. An air-gap armature characterized in that, in the armature winding, a semiconductive filling spacer having a corner portion that is sufficiently larger than a corner portion of the double-transposed conductor is interposed between the double-transposed conductor and the main insulation. winding.