JPS58108727A - Insulating coil for oil-filled electric apparatus - Google Patents

Abstract

PURPOSE:To obtain an insulating coil having high dielectric strength and high corona starting voltage by a method wherein a compound insulating layer consisting of oil-immersed insulating paper and polymeric group non-porous films is formed around a coil conductor. CONSTITUTION:Oil immersed insulating paper 22 and polymeric group non- porous films 23 are mutually superposed, and an insulating layer is formed by winding the required number of turns around a coil conductor 21. As the material of the oil-immersed insulating paper 22, craft paper is suitable when A-kind insulating oil is used as insulating oil and aromatic polyamide paper having high heat resistance is suitable when silicon oil having high heat resistance is used. As the polymeric group non-porous films, a film such as polyethylene terephthalate or the like having high dielectric strength value and high heat resistance can advantageously be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulated coil used in oil-filled electrical equipment such as oil-filled transformers and oil-filled paddles.

As shown in FIG. 1, a conventional insulated coil consists of a coil conductor 12 wrapped around a single insulating paper 12 such as oil-impregnated insulating paper or a polymeric nonporous film. It had been. However, when comparing those using oil-impregnated insulating paper and those using nonporous polymeric film, the former has a lower dielectric strength than the latter, and the latter has a lower corona onset voltage than the former. There was a drawback.

This invention was made to eliminate the above-mentioned drawbacks, and its purpose is to provide an insulated coil with high dielectric strength and high corona initiation voltage.

Next, one embodiment of the present invention will be described with reference to the drawings. Second
In the figure, 21 is a coil conductor, 22 is an oil-impregnated insulating paper, and 23 is a polymeric nonporous film. The oil-impregnated insulating paper 22 and the polymeric non-porous film 23 are stacked on top of each other and wound around the coil conductor 21 the required number of times to form an insulating layer.

FIG. 3 shows the structure of the insulating layer formed between the coil conductor 21 having the structure shown in FIG. 2 and the adjacent coil conductor 21 when the coil conductor 21 is wound into a coil. ing. The oil-impregnated insulating paper 22 has tk1 to tk, respectively.
kn'' thickness, and a polymeric non-porous film 2
3 have a thickness of t, 1 to t p n, respectively, and it is assumed that there is a potential difference V between the mutually adjacent coil (3) conductors 21, 21'.

In such an insulating configuration, the electric field strength EK within the oil-impregnated insulating paper 22 is equal in all layers and is expressed by the following equation.

However, tp-tp1+tp2..., +1pntk-
1kl"k2..., +tI(nε,: Dielectric constant ε of oil-impregnated insulating paper: Dielectric constant of polymer non-porous film On the other hand, as in the conventional insulation configuration, the same insulation is applied between all coil conductors. When an oil-impregnated insulating paper having strength and dielectric constant is provided, the electric field strength Ek within the oil-impregnating insulating paper is expressed by the following equation.

Ek−−□ ・・φ(2) ・k(ζ) However, T−tp+tk From equations (1) and (2), if εk>5, E′k>
Ek(4). Therefore, in the composite insulation structure shown by equation (1), the insulation strength of the oil-impregnated insulating paper does not change even if its thickness changes, so the total edge thickness T = tk + t, ) is increased until Ek = Ek. It is possible to reduce the electric field strength within the oil-impregnated insulating paper. Therefore, the total edge thickness T' of the composite insulation structure is as follows, and the insulation thickness between both coil conductors 21 and 21 can be greatly reduced.

Furthermore, since the oil absorption rate of the polymer nonporous film 23 is much lower than that of oil-impregnated insulating paper, voids tend to remain in the film and the corona onset voltage tends to be low. It is excluded by the adjacent oil-impregnated insulating paper.

Figure 4 shows the relationship between the dielectric constant of the polymer nonporous film used and the reduction rate of the thickness of the insulating layer of the present invention when the thickness of the conventional insulating layer is multiplied by 100. There is. Also the fifth
The figure shows the relationship between the total edge thickness and the pressure resistance value when the present invention is applied, using kraft paper [There is no particular restriction on the way the film 23 is wrapped, but the polymer nonporous film 23 has a butted structure. , and it is preferable to have an alternating arrangement of single-layer windings, and the first layer in contact with the surface of the coil conductor is preferably made of oil-impregnated insulating paper.

Furthermore, the material for the oil-impregnated insulating paper 22 is kraft paper when class A insulating oil is used as the insulating oil, and aromatic polyamide paper with high heat resistance when using silicone oil with high heat resistance. is suitable. Further, as the polymeric non-porous film, a film such as polyethylene terephthalate, which has good pressure resistance and heat resistance, can be advantageously used.

As described above, according to the present invention, around the coil conductor,
By forming a composite insulating layer consisting of oil-impregnated insulating paper and nonporous polymeric film, the shortcomings of the individual insulating materials are mutually compensated for, resulting in an insulated coil with excellent insulating properties. It has the effect of being

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional insulated coil, FIG. 2 is a sectional view of an insulated coil according to an embodiment of the present invention, and FIG. 3 is an explanatory diagram showing the structure of the insulating layer of the insulated coil of FIG. Figure 4 shows the relationship between the dielectric constant of a polymeric non-porous film and the reduction rate of the thickness of the insulating layer.
Oil-impregnated insulating paper, 23...Polymer-based nonporous film. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Makoto Kuzuno - (and 1 other person) 1,゛(l) 弗: 5 Danzaru, Souko Meiatsu) Written amendment to the procedures for the separation (voluntary) ■June 4, 1985 Dear Commissioner of the Japan Patent Office■, Display of the incident Patent application 1986-208642 +
32. Name of the invention: Insulated coil for oil-filled electrical equipment 3. The person making the correction shall make the correction as 100. 5. Column 6 for detailed explanation of the invention in the specification to be amended Contents of the amendment + 11 Specification 1, page 2, section 16, amend "around the conductor 12" to "around the conductor 11" . (2) In the 5th section of page 4 of Specification 1, the statement [■ has been amended. (3) In Specification 1, page 5, No. 2, No. 3, the statement ``Even if the thickness of the oil-impregnated insulating paper increases, we will not worry about it.'' will be deleted. (4) In Specification 1, page 6, 4th ladle, there is a phrase "assuming the thickness of the insulating layer is 100".

Claims (1)

[Claims] (1) A composite insulating layer formed by alternately winding oil-impregnated insulating paper and a non-porous polymer film is provided around the coil conductor. Insulated coil for oil-filled electrical equipment. (2) The insulated coil for oil-filled electrical equipment according to claim 1, wherein the non-porous polymeric film has a butted structure. (3)=An insulated coil for oil-filled electrical equipment according to claim 1 or 2, in which only one layer of polymer-based nonporous film is wound. (41 O = The first layer in contact with the surface of the coil conductor is oil. The insulated coil for oil-filled electrical equipment according to any one of claims 1 to 3, which is made of impregnated insulating paper. ) When the insulating oil used is Class A insulating oil, ≠≠ the oil-impregnated insulating paper is kraft paper, and the ↓ needle polymer-based nonporous film is polyethylene terephthalate film. Claim 1 The insulating coil for oil-filled electrical equipment according to any one of Items to Item 4. (6) In the case where the insulating oil used is silicone oil, - the oil-impregnated insulating paper is aromatic polyamide paper; , Claims 1 to 5, wherein the i-erect polymer nonporous film is a polyethylene terephthalate film.
An insulated coil for oil-filled electrical equipment as described in any of the above.