JPH0453110A - Gas insulated transformer winding - Google Patents

Abstract

PURPOSE:To improve a dielectric strength by a method wherein the surface of a transposed cable is coated with semi-solid insulating material and, after the surface is molded, solid insulating material is applied to the molded surface. CONSTITUTION:A conductor of a gas insulated transformer winding is composed of a transposed cable 1 whose surface is coated with semi-solid insulating material 2 such as silicone gel or polybutadiene gel and covered with an insulating covering 3. After the coated surface is molded, a plurality of layers of insulating papers or plastic films are applied to the surface to form the insulating covering 3. The conductor having a construction as described above is wound with a required number of turns to form the transformer winding. In the gas insulated transformer winding having a construction as described above, small gas gaps 4 which are formed on the surface of the transposed cable 1 and are weak points of insulation in the conventional constitution are filled with the semi-solid insulating material 2 to avoid the degradation of dielectric strength.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION Field of Industrial Application The present invention relates in particular to gas insulated transformer windings with an improved insulation configuration of the windings.

(Prior technology) Gas insulated transformers that use nonflammable insulating gas such as SF6 gas instead of conventional insulating oil as the insulating medium are being applied in substations and underground substations around large cities from the perspective of disaster prevention. It is being considered.

However, while the breakdown electric field of insulating oil depends on the gap length and becomes higher when the gap length is short, the breakdown electric field of insulating gas has almost no gap length dependence, and the breakdown occurs at the highest point of the electric field. It is an electric field dependent type that originates from .

Furthermore, in a composite insulation configuration such as a transformer, the electric field in the gas portion is higher than that in the insulating oil due to the difference in dielectric constant. Therefore, it is very important to eliminate electric field inequalities in the insulation configuration of gas insulated transformers.

(Problem to be Solved by the Invention) However, when a transposed cable is used as the wire in the winding of a gas insulated transformer, the gap between the conductor 1 and the solid insulator 3 as shown in FIG. 4 becomes a minute gas gap, and the electric field in this part 4 becomes extremely large compared to other parts. As mentioned above, such a small gap is
This has not been a major problem because the insulation structure using insulating oil has a high dielectric breakdown electric field. However, in the case of gas insulation, the electric field is highest at this minute gap, which causes a reduction in the insulation strength of the winding.

An object of the present invention is to provide a gas-insulated transformer winding with improved insulation strength by improving the insulation structure of the minute gas gap that exists between the transposed cable and the wire insulator. be.

[Structure of the invention] (One step to solve the problem) The gas insulated transformer winding of the present invention is made by applying semi-solid insulation + 4 materials to the surface of the dislocated Keple 1, forming the surface, and then insulating the outside with solid insulation. It is characterized by being coated with 4 materials.

(Function) The gas insulated transformer winding of the present invention configured in this manner functions as if a semi-solid insulating material were filled into the minute gap that conventionally existed in the conducting wire.

Therefore, the insulation of gas-insulated transformer windings1. The insulation strength is improved because the small gas gap, which was a weak point in the insulation, is eliminated.

(Example) The present invention will be described below with reference to an example shown in FIG. In FIG. 1, the strands forming the gas insulated transformer winding of the present invention are insulated after coating and surface molding a semi-solid insulating material 2 (silicon gel, polybutadiene gel cavity) on the surface of a transposition cable 1. Wrapping multiple layers of paper or plastic film 1. The insulating coating 3 was applied [7°]. The first conducting wire constructed in this way is wound a predetermined number of times.1. The transformer winding is constructed using the following steps.

The gas insulated transformer winding of the present invention configured in this manner fills the minute gas gap 4 on the surface of the transposed cable 1, which was the weak point of conventional insulation, with semi-solid insulation + material. This eliminates the low F of insulation strength.

As mentioned above, by constructing the transformer winding using a wire filled with semi-solid insulating material 2 between the transposed cable and the wire insulator 3, this weak point of conventional insulation can be overcome. The small gas gap 4 on the surface of the transposed cable 1 is eliminated, a transformer winding with high insulation strength can be obtained, and a gas insulated transformer with high insulation reliability can be constructed.

In FIG. 1, a transposition cable 1 is explained, but the present invention is not limited to transposition cables. A similar effect can be expected for lines.

Effects of the Invention C As shown in J-, in the gas insulated transformer of the present invention, as the strands constituting the transformer winding, a strand filled with a semi-solid insulating material between the transposed cable and the strand insulator is used. By using wires, it is possible to eliminate minute gaps, which were the weak points of conventional insulation, making it possible to obtain transformer windings with high insulation strength and providing gas-insulated transformers with high insulation reliability. .

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the gas insulated transformer winding of the present invention, and FIG. 2 is a sectional view of a conventionally used wire. 1...Translocation cable 2...Semi-solid insulating material 3
・・・Element wire insulation wave S 4...Gap attorney Patent attorney I Yoshiaki Inomata (and 1 other person) 1/ No. 211

Claims (1)

[Claims] A gas-insulated transformer winding characterized in that the conductor surface of a transposed cable is coated with a semi-solid insulating material, and the outside thereof is coated with a solid insulating material.