JPH071784Y2 - Gas insulated induction - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] This invention uses an insulating gas composed of sulfur hexafluoride (SF ₆ ) as an insulating medium to seal a gas in a hermetically sealed container containing an iron core and windings. Insulation induction device.

[Conventional technology]

FIG. 2 is a sectional view of an essential part showing an insulating structure of an end portion of a high voltage winding of a gas insulated induction electric device. This figure is a cross-sectional view of a concentric arrangement structure having a symmetry axis on the left side of the figure, and a cross section on the left side of the symmetry axis is omitted in the drawing. The high voltage winding 4 is a disk coil formed by stacking and winding electric wires coated with insulation in the radial direction, which is the left and right direction in the figure, and further stacking them in the axial direction, which is the vertical direction in the figure, with an insulating spacer interposed therebetween. It is composed of layers and is usually called a disk winding. Illustration of the detailed structure of the high-voltage winding 4 is omitted. The shield ring 2 is provided on the upper end of the high-voltage winding 4 via an insulating spacer 3. In the shield ring 2, the corners on the inner diameter side and the outer diameter side in the upper part of the drawing are angled with a large radius.
This is for alleviating the concentration of the electric field generated in this portion when the high voltage winding 4 is in a high voltage state. On the inner diameter side of the high-voltage winding 4 on the left side of the drawing, there is a low-voltage winding in the case of a transformer, which is one of the induction electric generators, and an iron core in the case of a shunt reactor. In the insulation configuration with the low voltage electrode such as the coil winding or the iron core, the electric field is concentrated at the end portion of the shield ring 2, which is the weakest point in the insulation. The reason why the shield ring 2 is provided to obtain a large R is to improve this weakest point.

A cooling duct is provided on the inner diameter side of the high-voltage winding 4 for allowing insulating gas to flow from the bottom to the top as a cooling medium for cooling the high-voltage winding 4, and as a spacing piece for securing this cooling duct. The duct piece 1 is provided. The duct piece 1 has a rectangular horizontal cross section and is made of an insulating material which is elongated in the axial direction which is the vertical direction of the drawing. The duct piece 1 is arranged at equal intervals in the circumferential direction with a space between adjacent ones. Insulation gas flows in this gap and the high voltage winding 4
The conductor is cooled by coming into contact with the conductor.

[Problems to be solved by the device]

By the way, as is well known, when insulators having different dielectric constants are mixed between the high-voltage electrode and the low-voltage electrode, there is a characteristic that the proportion of voltage sharing increases as the insulator having a smaller dielectric constant. The insulating material such as the duct piece 1 and the insulating spacer 3 is made of aromatic polyamide fiber and has a relative permittivity of about 3, whereas the insulating gas has a relative permittivity of 1. In the insulation configuration shown in FIG. 2, when a high voltage such as a test voltage is applied to the high voltage winding 4, the electric field is concentrated on the upper left end of the shield ring 2 as the end of the high voltage electrode in the figure. Therefore, in order to reduce this concentration rate, the corners of the shield ring 2 are rounded with a large curvature as shown in the figure. In this insulating structure, the space 5 between the duct piece 1 and the shield ring 2 is further made into an insulator having a small dielectric constant when the above-mentioned insulators having different dielectric constants are mixed because of the duct piece 1. Since the electric field is concentrated, the electric field strength of the void 5 is further increased, and as a result, the dielectric strength of the high voltage winding 4 is reduced. Therefore, the required insulation strength is ensured by increasing the insulation distance of the high-voltage winding 4 from the low-voltage electrode. However, increasing the insulation distance in this way increases the size of the entire gas-insulated transformer. As a result, there arises a problem that it becomes a major cause of weight increase and price increase.

This invention proposes a gas that can secure the dielectric strength of a high voltage winding without increasing the weight or increasing the price by lowering the electric field in the void portion of the shield ring end without increasing the insulation dimension. An object is to provide an insulation induction electric device.

[Means for Solving the Problems]

According to the present invention to solve the above-mentioned problems, a cylindrical winding wire, a shield ring made of a conductor provided on at least one end of the winding wire through an insulating spacer, and a winding wire A gas-insulated dielectric electric appliance comprising: a duct piece provided over the entire length in the axial direction of a winding wire, including the shield ring closely arranged on the inner diameter side at equal intervals in the circumferential direction; The outer diameter side of the axial tip facing the ring shall be cut out.

[Action]

In the structure of the present invention, between the shield ring of the duct piece provided in contact with the inner diameter side of the high-voltage winding and the outer diameter side of the axial tip end that is opposed to the shield ring, the outer peripheral side of the shield ring is cut away from the duct piece at the inner diameter side end Increase the size of the void part of
By reducing the thickness of the duct piece, the size of the duct piece with a large relative permittivity decreases and the size of the void with a small relative permittivity increases, so the electric field concentration in this void decreases and the value of the electric field strength decreases. To do.

〔Example〕

The present invention will be described below based on embodiments. FIG. 1 is a sectional view of an essential part of a gas-insulated induction electric machine showing an embodiment of the present invention, and the same members as those in FIG.

The duct piece 10 has a tip 12 facing the shield ring 2.
Notch the outer diameter side of this, and this tip 12 and shield ring 2
The size of the space 51 between the space and the space is increased.
The central portion 11 of the duct piece 10 has the same structure and dimensions as the prior art shown in FIG. 2 because it is necessary to support the high-voltage winding 4 on the inner diameter side and secure the cooling duct as described above. An air gap (not shown) also exists between the high voltage winding 4 and the central portion 12 of the duct piece 10. In this portion, the high voltage winding 4 and the low voltage electrode (not shown) such as the iron core are parallel to each other. Since they are opposed to each other and the electric field is not concentrated, they do not affect the dielectric strength of the high-voltage winding 4.

The size of the void 51 having a small relative permittivity is increased, and the thickness of the tip portion 12 of the duct piece 10 having a large relative permittivity is correspondingly reduced, whereby the electric field concentration in the void 51 is relaxed, and FIG. The electric field strength of the void 51 is lower than that of. Since the dielectric breakdown characteristic of the insulating gas is generally determined by the electric field strength regardless of the size of the void portion, even if the size of the void portion 51 is increased, the dielectric strength of the high-voltage winding 4 increases if the electric field strength of this portion decreases. It will be. By the way, in the case of insulating oil used as an insulating medium for large-capacity and induction electric appliances such as ultra-high voltage transformers and reactors, it has the insulating property that the breakdown electric field strength increases as the oil gap size decreases. Therefore, even if the electric field strength is reduced, the oil clearance may be increased, and the dielectric strength may be reduced. Therefore, as in the present invention, the end of the shield ring 2 where the electric field is concentrated is cut out by notching the tip of the duct piece. It is usually impossible to expect an increase in dielectric strength by increasing the size of the oil gap. For this reason, oil-insulated transformers and high-voltage high-voltage winding ends of reactors usually have an insulation configuration as shown in Fig. 2. In order to further improve the dielectric strength, shield For example, an insulating coating may be applied to the ring 2 or an insulating barrier may be provided to subdivide the oil gap. In this sense, this invention is effective only when the insulating medium is an insulating gas.

As is apparent from FIG. 1, when the present invention is adopted, the inner diameter side of the shield ring 2 is not supported by the duct piece 10, and the shield ring 2 may be easily displaced in the left and right directions in the drawing. However, in reality, the high-voltage winding 4 including the shield ring 2 is provided with a large compressive force in the vertical direction, so that the shield ring 2 is affected by the frictional force between the shield ring 2 and the insulating spacer 3. There is no deviation. The insulating spacer 3 is also supported by the frictional force between the insulating spacer 3 and the high-voltage winding 4, so that the tip of the duct piece 10
There is no problem even if the notch size of 12 is increased close to the height of the high voltage winding 4.

[Effect of device]

As described above, the present invention cuts off the outer diameter side of the axial end of the duct piece on the inner diameter side of the high-voltage winding that faces the shield ring, and cuts the outer diameter side between the inner diameter side end of the shield ring and the duct piece. By increasing the size of the void having a small relative permittivity and reducing the thickness of the duct piece having a large relative permittivity, the electric field concentration in the void is relaxed and the value of the electric field strength is reduced. As a result, the dielectric strength of the high-voltage winding increases, and the insulation distance between the high-voltage winding and the low-voltage electrode can be shortened. The effect can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a gas-insulated induction machine showing an embodiment of the present invention, and FIG. 2 is a sectional view of an essential part of a conventional gas-insulated induction machine. 1,10 ...... Duct piece, 11 ...... Central part, 12 ...... Tip part,
2 ... Shield ring, 3 ... Insulation spacer, 4 ... High voltage winding, 5,51 ... Void.

Claims (1)

[Scope of utility model registration request] 1. A cylindrical winding wire, a shield ring made of a conductor provided on at least one end of the winding wire through an insulating spacer, and in close contact with the inner diameter side of the winding wire in the circumferential direction. A gas-insulated induction electric machine, comprising: a duct piece provided over the entire length in the axial direction of a winding wire, including the shield ring arranged at equal intervals, in the axial tip end of the duct piece facing the shield ring. A gas-insulated induction electric appliance characterized in that the outer diameter side is cut away.