SU1292059A1 - Support-insulation structure of high-voltage device - Google Patents

Abstract

The invention relates to high-voltage electrical equipment, in particular, to the structures of the reference insulation of the disconnectors. The purpose of the invention is to increase the dielectric strength of the insulating structure during phase overvoltages and to reduce the material intensity and size. An insulating structure 2 is mounted on a grounded footplate 1, on which two toroidal shields 3 and 4 are installed. The electrical strength of such a structure during phase overvoltages depends on the ratio of the radii of the axial lines of the high-voltage toroid 3 (R) and the grounded toroid 4 (К „ ) (1-0 ,, where Н ,, is the vertical distance between the axial lines of the screens; A 1.6 - 2.0. The high-voltage screen is located below the lower level of the metal reinforcement of the upper insulator, and the grounded screen of the footboard is higher metal level of the lower insulator armature by values of y, equal to l Hj,., where B is 0.5-0.7, Rj, is the radius of the axial line of the toroidal shields — grounded and high-voltage. 1 Cp f-ly, 3 Ill. § (Л 1C QD Ю О 01; о Ф11.1

Description

1129

The invention relates to high-voltage electrical equipment and can be specifically used in the construction of support insulation of disconnectors and high voltage busbars.

The aim of the invention is to increase the electrical strength of a structure during thunderstorm overvoltages and reduce its dimensions and material intensity.

Fig. 1 shows the support-insulator, structural design (DEC) of an electrical apparatus of high voltage, general view; FIG. 2 shows the dependences of 50% discharge voltages (and, §).

on the radius of the grounded toroid Rp at various sizes of the high-voltage toroid; in FIG. 3, the function of the relations R,. / H ,.

An insulating structure 2 is mounted on a grounded footplate 1 on which two toroidal shields 3 and 4 are installed. The electrical strength of such a structure during lightning surges depends on the ratio of the radii of the axial lines of the high-voltage toroid 3 (Ry) and the grounded toroid 4 (RO) Curves 1 , 1 for R 0.5 m, 2.2 - RT 1.0 m, 3, R 1.5 m, and different distances between the axial lines of the toroid Hc are reflected in Fig. 2. The experiments were carried out with the positive polarity of the thunderstorm pulse of form 1.2 / 50 (curves 1, 2 and 3 - bright points) and negative (curves 1, 2 and. 3 - blackened points).

For small values of R (Fig. 2), discharge voltages during thunderstorm pulses, o, tricative polarity, are less than for positive ones. This is due to the fact that with a negative polarity of the pulses, the spark does not develop from the negatively charged high-voltage screen, ja from the positively charged screen of the foot plate. An increase in К „at constant Hj, and R leads to a decrease in discharge voltages of positive polarity. At the same time, there exists an optimal radius of the grounded screen of the footplate, R °, at which the discharge voltages on the positive and negative polarity of the pulse are the same

The ratio, is a function of the ratio RT / HM (Fig. 3), which is well approximated by the expression

R

B 1, |

Ate (1 0.6 -).

n

In the practical implementation of the DEC with this screen system, by design considerations, some deviations of the optimal values R ° nVRT are possible. The analysis shows that if the allowable reduction in the discharge stresses of a structure by 3%, then the criterion for choosing the optimal screen system is the ratio

  ART / H "(1 - 0.6,),

where a 1.6 - 2.0.

When using polymer insulators, it is necessary to limit the intensity of the electric field in the body of the insulator.

To reduce the voltage, which is maximum near the top of the DEC, which is under high potential, and near the top of the footplate, high-voltage screen 3 should be installed below the lower metal part of the top of the DEC, which is under high potential, and screen 4 of the footplate - above the upper level of metal reinforcement lower isolator mounted on the footplate, respectively | But at a distance, and H, BR, where B 0.5 - 0.7. In this case, the voltage near the high-voltage | Troda electrode is limited to no less than | 95% of the maximum possible limit that can be obtained using the screen used.

The use of the invention makes it possible to reduce the height of the DEC by 10-15% and thereby reduce the consumption of materials, as well as to increase its electrical strength during thunderstorm overvoltages.

e.

45

Claims (2)

1. The support-insulating structure of a high-voltage apparatus is made in the form of a set of single Q insulators with metal fittings, a footplate and two toroidal screens — a high-voltage one installed on the top of the structure, and a grounded one — on the footplate, in order to increase the electrical strength of the insulating structure during thunderstorm overvoltages and reduce its material intensity and dimensions, these screens dimensions such that the ratio between the radii of the axial lines of the screens and the distance between the axial lines in the vertical is chosen in accordance with the ratio Rт / Hx (ten,), radius of the axial line of the grounded shield; footboard-radius of the axial line of the high-voltage screen, m; -coefficient whose value is in the range of 1.6 - 2.0; vertical spacing between the axial lines of the screens. 20594 2. POP.1 construction, characterized in that the high-voltage screen is located below the lower level of the metal reinforcement of the upper insulator, and the grounded screen of the foot plate is above the upper level of the metal reinforcement of the lower insulator by an amount equal to YN (, BR, where B is a coefficient whose value is in the range of 0.5-0.7; (ПТ1 radius of the axial line of toroidal screens (grounded or high voltage), m. w Copt. Kj ab O.f 0.2 0 0.2O.CH0.6 FIG. 3 Yag Neither 0.8 W Compiled by V. Popova Editor O. Golovach Tekhred L. Serdyukova Proofreader M. Pojo  ---.- - - - - - - - - Order 278/52 Circulation 699 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4