RU110862U1 - HIGH VOLTAGE INLAND WITH RESIN IMPAIRED PAPER INSULATION - Google Patents

Abstract

 1. The core of the high-voltage input containing a conductive metal pipe and superimposed with resin-impregnated multilayer paper insulation with equalizing plates, characterized in that the equalizing plates are equipped with electrodes that are located on the edges of the plates, electrically connected to them and made of electrically conductive tape by winding it together with the insulation layer, while the edges of the wound tape form the electrode profile. ! 2. The core according to claim 1, characterized in that the insulation can be made of crepe paper, and the electrically conductive tape is made of metal foil.

Description

The utility model relates to electrical engineering, namely, to waters in transformers and other high-voltage apparatuses, as well as to high-voltage cable couplings with capacitor-type insulation.

Using equalizing (capacitor) plates regulate the voltage distribution in the insulation of the bushings in the radial and axial directions. The number of plates in the bushings and couplings increases with increasing voltage. For bushings with paper-oil insulation for voltages of 110, 220, 330 and 500 kV, the number of plates (main and additional) is respectively 20, 40, 60 and 90./ V.S.Dmitrevsky, "Calculation and design of electrical insulation", Energoizdat . Moscow, 1981, p. 226 /.

Known designs of the cores of high voltage bushings with paper insulation impregnated with resin. Multilayer paper insulation with leveling plates impregnated with resin is applied to a current-carrying metal pipe. The design of paper insulation in these cores is different, and the leveling plates are made identically - plates of thin metal foil located between the layers of paper. / Utility model patents Nos. 38423, 41536, 80623, 86038, “High-voltage input core with paper insulation impregnated with resin” ./ The presented input core structures have the same drawback: “At the sharp edges of the lining there is a very uneven field with a significant component of tension directed along the layers of paper.

The field strength at a distance r from the edge of the electrode for r <0.1 d can be estimated by the following formula: where U is the voltage between the plates, d is the thickness of the insulation.

/ M.A. Greysukh, G.S. Kuchinsky, D.A. Kaplan, G.T. Messerman. “Paper-oil insulation in high-voltage structures”, Gosenergoizdat, Moscow-Leningrad, 1963, p. 24 /

The degree of heterogeneity of the electric field is characterized by the coefficient of field heterogeneity - K, equal to the ratio of the highest intensity E _max to the average intensity E _cf. At K> 3, the electric field is considered to be highly inhomogeneous.

Table 1 shows the results of calculating the electric strength. field E at the edge of the plate at a distance r for different insulation thicknesses d for the same average tension E _cf = 1.6 kV / mm and the voltage between the plates U = E _cf · d, as well as the values of r _p for which the electric the field is 4.8 kV / mm, and the field at the edge of the lining is highly inhomogeneous.

Table 1 : d mm : 2 3 : 12 : eighteen : U, kV : 3.2 4.8 : 19,2 : 28.9 : r mm : 0.1 0.01 0.15 0.1 0.01 : 0.6 0.1 0.01 : 0.9 0.1 0.01 : E, kV / mm : 4.05 12.8 4.04 4.95 16 : 4.04 9.9 31.3 : 4.0 12,2 40.8 : r _p mm : 0,07 0.1 : 0.42 : 0.64

With an increase in thickness d from 2 to 18 mm, the insulation region with a sharply inhomogeneous field expands from 0.07 to 0.64 mm.

Known methods for reducing the electric field at the edge of the lining. In the oil-barrier bushings, the edges of the plates are wrapped, and in the inlets with paper-oil insulation, additional plates are installed between the main plates.

In the case of using the first method in skeletons with paper insulation impregnated with oil or resin, the construction of the skeletons and the technology for their manufacture will become more complicated (in terms of winding the insulation, drying and impregnating it).

“The installation of additional plates does not eliminate a sharply inhomogeneous field at the edge of the upper lining and leads to the appearance of new sections with a sharply inhomogeneous field at the edges of the additional plates. However, the dimensions of each area with increased tension are smaller. This complicates the appearance of discharges and allows you to increase the allowable voltage ". (High voltage technique", under the general editorship of D.V. Rozevig, Energy, Moscow, 1976, p. 110).

In cable terminations, to reduce the electric field strength at the edge of the lining, a cylindrical screen is used, which is installed above the edge of the lining and electrically connected to the protected lining. “In this case, the electric strength in the region of the edge of the lining will be determined by the thickness of the insulation between the screen and the inner lining.” (M.A. Greysukh, G.S. Kuchinsky, D.A. Kaplan, G.T. Messerman, “Paper-oil insulation in high-voltage structures, Gosenergoizdat, Moscow-Leningrad, 1963, p. 53).

The task of this utility model was to develop the design of the core of a high-voltage input of a capacitor type with a slightly inhomogeneous field at the edges of equalizing plates with a smaller number of plates.

The technical result is achieved by the fact that in the core of the high-voltage input containing a current-carrying metal pipe and superimposed with resin-impregnated multilayer paper insulation with leveling plates, the leveling plates are equipped with electrodes that are located on the edges of the plates, electrically connected to them and made of electrically conductive tape by winding it together with the insulation layer, while the edges of the wound tape form the profile of the electrode.

The core insulation can be made of crepe paper 0.15-0.6 mm thick, and the electrically conductive tape can be made of metal foil 10-20 microns thick.

The electrical connection of the equalizing plate with the electrode can be carried out using electrically conductive glue.

Figure 1 shows the skeleton of a high-voltage input with equalizing plates equipped with electrodes in section.

The skeleton contains a current-carrying metal pipe 1, on which a resin-impregnated multilayer paper insulation 2 with leveling plates 3 is applied. The leveling plates are equipped with electrodes 4, which are located on the edges of the plates and are electrically connected to them. The electrodes are made of electrically conductive tape 5 by winding it together with an insulation layer 6, while the edges of the wound tape form the profile of the electrode.

The sizes and profile of the electrodes for each core structure are determined by calculation. Based on the selected electrode, its installation location in the insulation and the thickness of the crepe paper and foil used, the dimensions of the conductive tape (length, change in the width of the tape along its length) are calculated. As can be seen from figure 1, the edge of the first turn of the conductive tape overlaps the edge of the equalization cover, and the edges of the subsequent turns of the tape overlap the edges of the tapes of the previous turns. Between the turns of the tape is an insulation layer that is wound together with the tape. The thickness of this layer depends on the insulation structure of the skeleton and may be equal to the thickness of one or more paper webs. The thickness of the electron depends on the thickness of this layer. fields near the edge of the lining and the edges of the conductive tape.

Consider, as an example, a core for a voltage of 500 kV with 10 equalizing plates and an average insulation strength of E _cf = 1.6 kV / mm.

Tension between plates and the thickness of the insulation layer between the plates d = 18 mm

The calculation of the distribution of potential in isolation near the edge of the equalizing cover was carried out by the method of eliminating residues with a step of a square grid equal to 0.15 mm. (V.A. Govorkov, Electric and magnetic fields, Moscow, Energy, 1968, p. 388).

Electricity field E at the edge of the plate with the thickness of the insulating layer between the turns of the tape equal to 0.15, 0.3 and 0.6 mm, respectively, equal to 2, 2.58 and 3.18 kV / mm and electric. the field here is not strongly inhomogeneous, because K <3.

The proposed design of the core allows you to create a high-voltage input with paper insulation impregnated with resin, with greater electrical strength and fewer leveling plates.

Claims (2)

1. The core of the high-voltage input containing a conductive metal pipe and superimposed with resin-impregnated multilayer paper insulation with equalizing plates, characterized in that the equalizing plates are equipped with electrodes that are located on the edges of the plates, electrically connected to them and made of electrically conductive tape by winding it together with the insulation layer, while the edges of the wound tape form the electrode profile. 2. The core according to claim 1, characterized in that the insulation can be made of crepe paper, and the electrically conductive tape is made of metal foil.