JPS59149763A - Insulating method of connecting part of electric device winding - Google Patents

Abstract

PURPOSE:To improve the withstand voltage by providing a protecting winding between the insulating layer of a winding for an electric device and an insulator filler, and insulating to the ground, thereby strengthening the weak insulation part of the connecting part. CONSTITUTION:A protective layer 5 is wound of an insulating material adapted for an insulating layer 3 of a winding for an electric device at the end of an insulating filler 2 to be inserted into a connecting part. Then, the filler formed in the shape substantially matched previously to the shape of the connecting part is inserted into the connecting part, and an insulating material adapted for the winding of the electric device is wound and insulated to cover the entirety, thereby forming an insulation to the ground. A tape having a releasing action and a tape for winding the insulated connecting part are wound on the insulated connecting part formed in this manner, and the entirety is uniformly heated by a heating device.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method of insulating the windings of electrical equipment used mainly in industrial water or in a water-sealed state [Technical background of the invention and its problems] ] Conventionally, insulating the connection parts such as the neutral point of the windings of electrical equipment used underwater or in a water-sealed state, for example when winding cross-linked polyethylene insulated wire at ℃, was performed as shown in Figure 1. was. That is, first, after the conductors 1 of the windings are connected to each other, an insulating filler 2 made of thermoplastic such as polyethylene is inserted in a shape that almost matches the shape of the connection part, which is a gap between the windings at the connecting part. Fill. Then, a ground insulation 4 is formed to cover the conductor 1, the insulating filling 2, and the insulating layer 3 of the crosslinked polyethylene insulated wire. The thus formed connection portion insulation was integrated by heating and fusing with a ribbon heater or the like.

In this prior art insulating structure for connecting parts of electrical equipment windings, the inside of the insulating layer after heat fusion is insulated and filled with 2 fillers due to differences in heat transfer during heat fusion, as shown in Figure 2. It has been observed that the ground insulation material subjected to stress often deforms into a concave shape before it reaches its melting point. When this happens, this end @A” has the earth potential #: Some water has entered in a complicated manner,
All dielectric breakdown locations appeared in this part, partly because the electric field strength was stronger than in other parts. Even if the insulation thickness of the connection part is increased, the breakdown voltage remains as low as 70 to 80% of the original dielectric strength of the crosslinked polyethylene insulated wire, which has the disadvantage that it becomes the weakest point in the winding of electrical equipment.

Further, in order to prevent this, it is sufficient to allow the filling 2 to reach its melting point first, but it is very difficult to heat the filling 2 locally from the inside using equipment or electric heating. Naturally, the long-term reliability of connection insulation using these conventional methods could not be said to be sufficient.

[Purpose of the invention]

The present invention was made to solve these problems, and strengthens the weak points of the connection insulation to improve the withstand voltage.
How to insulate the connections of electrical equipment windings with high reliability? aim to provide.

[Summary of the invention]

In order to achieve this object, in the method for insulating the joints of electrical equipment windings according to the present invention, an insulating filling is applied to the acute-angled portions formed by the plurality of connecting conductors, and an insulating layer of the connecting conductors is insulated. An insulating protective layer is provided in between.

[Embodiments of the invention] An embodiment of the present invention will be described with reference to FIG.

First, a protective layer 5 is wrapped around the end of the insulating stuffing 2 to be inserted into the connection part, and then a protective layer 5 that is suitable for the electrical equipment winding insulation layer 3 is wrapped, and then the protective layer 5 is wrapped in a shape that almost matches the shape of the connection part. Insert the insulating filling 2 into the connection part made in the shape of Form.

The connection part insulation formed in this way is further wrapped with a tape having a mold release effect and a tape that presses and wraps the connection part insulation, or is covered with a mold, and these insulating filler 2 and insulation layer 3
, a protective layer 5 and a ground insulation 4, the whole is uniformly heated by a heating device such as a ribbon heater or an infrared heater, thereby obtaining an integrated insulating structure for connecting portions of electrical equipment windings.

In this way, a protective layer 5 is formed between the insulating filling 2 and the insulating layer 3.
? The provision of this feature prevents the end of the insulating layer 3 from directly applying stress to the insulating layer 3 during heating, and furthermore, the insulation thickness in this area is increased and the dielectric strength is strengthened, making it extremely 48. A highly reliable connection insulation structure is provided. At the same time, there is a possibility that microvoids between the insulating d6 materials 2 and interfaces that may introduce impurities may occur, and the long-term reliability will also be affected.

It is preferable to use the same insulating material as the insulating material of the insulating layer 3 of the equipment winding as the insulating material of the insulating filling 2, the protective layer 5, and the ground insulation 4.

In general, thermoplastic organic polymer materials such as crosslinked polyethylene, ethylene propylene, and polypropylene are used as insulating materials for the windings of electrical equipment used underwater or in a water-sealed state. Therefore, for example, if cross-linked polyethylene is used for the insulating layer 3 of an electrical equipment winding, it is optimal to use cross-linked polyethylene for the insulating filler 2, protective layer 5, and ground insulation 4; Depending on the conditions of use, cross-linked polyethylene may be used for the insulating layer 3 and insulating filling 2, and ethylene propylene may be used for the protective layer 5 and ground insulation 4g.If these thermoplastic polymeric materials are used in various combinations, You can also do it.

FIG. 4 shows a measurement example illustrating the effects of the present invention, in which the ratio of breakdown voltages ri? It was done. The connected electric wire is 1. An electron beam cross-linked polyethylene coated electric wire of O-ring was used. The insulating filling is also made from a cross-linked polyethylene block machined to match the shape of the acute corner of the connection. In addition, the ground insulating layer at the connection part has a gel fraction of 5.
It was wound with 0% electron beam crosslinked polyethylene tape. In the case of the conventional method (a), it was formed according to FIG. 1, and in the case of the present invention (b), according to FIG. . In the fourth factor, the broken line is the breakdown voltage of the wire. In the method according to the present invention, compared to the conventional method a,
It can be seen that the breakdown voltage is the same as above and the variation is also reduced. Furthermore, it can be seen that the value is higher than the original value of the wire.

〔Effect of the invention〕

In the method of insulating the connection part of the electrical equipment winding of the present invention, a protective winding is provided between the insulating layer of the electrical equipment winding and the insulating filling, and ground insulation treatment is performed. There,
No stress is added to the insulation layer of electrical equipment windings,
Since the breakdown stress exceeds the dielectric strength inherent to the electrical equipment winding, it is possible to provide connection insulation with high reliability over a long period of time, even under usage conditions of high temperature and high pressure, for example.

[Brief explanation of the drawing]

No. 1N is a cross-sectional view showing the structure of connection insulation of electrical equipment winding manufactured by the conventional method, and Fig. 2 is No. 14 (1X).
FIG. 3 is a cross-sectional view showing the structure of the insulation of the connection part manufactured by an embodiment of the method of the present invention, and FIG. It is a graph showing a comparison of breakdown voltages. ■...Conductor 2...Insulating filling 3...
- Insulating layer 4... Ground insulation 5... Protective layer. Agent: Patent attorney Noriyuki Chika (and 1 other person) Figure 1

Claims (1)

[Claims] An electrically insulating protective layer is formed on the insulating coating near the connection point where conductors of a plurality of windings each having an insulating coating are connected, and an electrically insulating wedge-shaped body is formed so that its bottom corner portion is in contact with the protective layer. A method for insulating a connection part of an electrical equipment winding, characterized in that a comb is inserted between the connected windings, and an insulating coating is applied to cover the protruding part of the casing.