RU139737U1 - HIGH VOLTAGE GAS-FILLED VOLTAGE TRANSFORMER - Google Patents

Abstract

A high-voltage voltage transformer containing an insulating porcelain body mounted on a metal base and filled with insulating gas, inside of which an insulating cylinder of high-strength insulating material is installed, with a magnetic circuit inside of it with screens and a metal current lead pipe, with at least one main and additional low windings voltage wound on the rod, and with a high voltage winding that is wound over the main winding and closed by an electrostat a shield connected to its linear end and connected to the upper metal cover tightly covering the insulating cylinder of high-strength insulating material, by means of a metal current lead pipe fixed in a cylindrical electrostatic screen, characterized in that the walls of the insulating cylinder are made of high-strength insulating material, at least one through hole.

Description

The proposed utility model relates to electrical engineering and can be used in the design of measuring transformers for voltage high and ultra high voltage with gas filling.

Currently, a high-voltage outdoor voltage transformer is known (DE 2452056 A, IPC: H01F 40/04, published 05/20/1976) - [1], containing an insulating porcelain body mounted on a metal base and filled with an insulating medium, inside of which there is a rectangular magnetic circuit with screens covering the yokes, with a metal pipe of the current lead, with the main and additional low voltage (LV) windings wound on the rod, and with a high voltage layer winding (HV), which is wound over the main low voltage and closed by an electrostatic screen connected to its linear end. The interlayer insulation of the VN winding is made of a polymer film.

This design of the transformer [1] provides a uniform distribution of lightning voltage across the HV winding. In addition, the use of polymer films for interlayer insulation provides the required electric strength of the HV winding when exposed to a lightning impulse voltage.

However, the design of this transformer [1] has low reliability due to the danger of explosion of the transformer, which is caused by complex technological operations when winding the windings and installing the active part of the transformer in a porcelain case and making the winding screen.

The closest in technical essence to the proposed voltage transformer and selected as a prototype is a high voltage voltage transformer (RU 2124246 C1, IPC: H01F 38/26, published 12/27/1998) - [2], which contains mounted on a metal base and filled with insulating gas an insulating porcelain case, inside of which an insulating cylinder of high-strength material is mounted, mounted on the lower flange of the transformer by means of a metal ring and filled with insulating gas, with a rectangular magnetic circuit inside it with screens covering the yokes, with a metal current-conducting pipe, with the main and additional low voltage windings wound on the rod, and with a high voltage winding wound over the main low voltage winding and closed by an electrostatic shield connected to its linear end and made in the form of a cylinder with a through cut along its generatrix.

The installation inside the porcelain case in the transformer [2] of an insulating cylinder of high strength material, which is hermetically fixed inside the porcelain case, leads to the fact that the volumes enclosed between the porcelain case and the insulating cylinder of high strength material and inside the insulating cylinder, which is closed by a metal flange, must It must be filled and pumped separately and the gas pressure in each volume must be controlled separately.

In addition, each volume must be equipped with a device to prevent an emergency increase in pressure exceeding the allowable pressure in each of the volumes in the device [2].

These circumstances lead to a significant complication of the design of the device, the technology of its manufacture and an increase in the cost of a voltage transformer [2].

In addition, there is the possibility of damage to the insulating cylinder of high strength material, leading to the same gas pressure in the porcelain body as in the insulating cylinder, reduces the reliability of the device as a whole.

The objective of the proposed utility model is the creation of a voltage transformer design, which provides the possibility of simultaneously filling / pumping out the volume between the inner surface of the porcelain body and the outer surface of the insulating cylinder from high-strength insulating material, as well as the volume that is covered by the insulating cylinder, and controlling the gas pressure in them simultaneously.

The technical effect of using the proposed technical solution is:

- a significant reduction in the cost of the device due to the abandonment of part of the equipment for measuring gas pressure and gas injection / pumping;

- facilitation of manufacturing and maintenance technology during operation.

The solution of the problem and the corresponding technical effect are achieved by the fact that in a high-voltage voltage transformer containing an insulating porcelain body mounted on a metal base and filled with insulating gas, an insulating cylinder made of high-strength insulating material with a magnetic core with shields and a metal current lead inside it is installed, with at least one main and additional low voltage windings wound on the rod, and with high-voltage current, which is wound over the main winding and closed by an electrostatic shield connected to its linear end, and connected to the upper metal cover tightly closing the insulating cylinder of high-strength insulating material, by means of a metal current-conducting pipe fixed in a cylindrical electrostatic screen, while at least one through hole is made of the walls of the insulating cylinder of high-strength insulating material.

The presence of through holes in the walls of the insulating cylinder allows you to simultaneously fill or pump out both volumes and, therefore, maintain the same pressure in them during normal operation. In the event of an emergency increase in pressure in an insulating cylinder made of high-strength insulating material, through holes made in its walls, the diameters of which are selected experimentally or calculated, can simultaneously limit the rate of increase in gas pressure in the insulating cylinder itself and the pressure inside the porcelain body.

Comparison of the proposed voltage transformer with the prior art and the lack of a description of similar technical solutions in known sources of information allows us to conclude that the proposed device meets the criterion of "novelty."

The figure schematically shows in section an example of a practical implementation of the proposed design of a gas-filled voltage transformer.

Proposed in FIG. The high-voltage transformer contains: an insulating porcelain case mounted on a metal base (not shown) - 1, filled with an insulating medium (gas); magnetic circuit - 2, for example, of rectangular shape; electrostatic screens - 3, 4 and 5, covering two side and one lower yoke of magnetic circuit 2; metal pipe - 6 current leads; main winding - 7 low voltage (LV); additional winding - 8 low voltage; high voltage winding (VN) - 10; electrostatic screen - 11, covering the high voltage winding 10; insulating cylinder - 12, made of high-strength insulating material; ring - 13; metal cover - 14; bottom flange - 15 transformers; lower metal ring - 16; half rings - 17 and 18 for attaching the lower flange 15 to the porcelain body 1; upper flange - 19 transformers; the upper half rings - 20 and 21 for attaching the upper flange 19 to the porcelain body 1.

In this case, the electrostatic screen 11 can be made in the form of a cylinder with a through cut along its generatrix.

In addition, the transformer is equipped with a contact rod - 22, which galvanically connects the metal cover 14 with the upper flange 19.

At the same time, the insulating cylinder 12, in which the magnetic circuit 2 with electrostatic shields 3, 4, 5 and the current lead pipe 6 is placed, as well as the main 7, additional 8 low voltage windings and high voltage winding 10, is installed inside the insulating porcelain case 1.

Moreover, at least one main 7 and additional 8 low-voltage windings are wound on the rod 9 of the magnetic circuit 2, and the high-voltage winding 10, which is wound on top of the main winding 7, is closed by an electrostatic shield 11 connected to its linear end.

The insulating cylinder 12 is tightly closed by means of the ring 13 with a metal cover 14 and mounted on the lower flange 15 of the transformer by means of the lower metal ring 16.

At the same time, at least one through hole is made in the walls of the insulating cylinder 12 — 23 of a small diameter, the value of which is determined experimentally or by calculation.

Proposed in FIG. high voltage voltage transformer operates as follows.

When pumping the air of their transformer, the through holes 23 made in the walls of the insulating cylinder 12 from high-strength insulating material allow evacuating the air at the same residual pressure in both volumes formed:

- the inner surface of the porcelain body 1, the outer surface of the insulating cylinder 12 of high-strength insulating material and facing the porcelain body 1 side of the metal cover 14, the upper flange 19 and the lower flange 15;

- the inner surface of the insulating cylinder 12 of high-strength insulating material, the lower flange 15 and the inner side of the metal cover 14, hermetically closing the insulating cylinder 12, made of high-strength insulating material.

When filling the volumes evacuated in one go with insulating gas, the gas pressure in both volumes also turns out to be the same, which requires the use of only one set of control and measuring equipment for measuring gas pressure or its density and one set of equipment for pumping and filling the transformer volumes with insulating gas.

In the emergency mode that occurs inside the insulating cylinder 12 of high-strength insulating material, the rate of increase in pressure inside the volume limited by the inner surface of the porcelain body 1 and the outer surface of the insulating cylinder 12 is significantly lower than the rate of increase of pressure inside the volume bounded by the inner surface of the insulating cylinder 12. And, as a consequence, the pressure in the volume bounded by the inner surface of the porcelain body 1, due to the throughput capabilities of the through holes 23, is also substantially less than the pressure inside the volume bounded by the inner surface of the insulating cylinder 12 of high-strength insulating material.

Therefore, the presence in the walls of the insulating cylinder 12 of at least one small hole 23 leads to an increase in the reliability of both the proposed transformer during its operation, and by reducing the number of complex vacuum equipment and control and measuring equipment used. In addition, a significant reduction in cost of the device is achieved by reducing the number of used instrumentation and process equipment needed to prepare the voltage transformer for testing and operation.

Claims (1)

A high-voltage voltage transformer containing an insulating porcelain body mounted on a metal base and filled with insulating gas, inside of which an insulating cylinder of high-strength insulating material is installed, with a magnetic circuit inside of it with screens and a metal current lead pipe, with at least one main and additional low windings voltage wound on the rod, and with a high voltage winding that is wound over the main winding and closed by an electrostat a shield connected to its linear end and connected to the upper metal cover tightly covering the insulating cylinder of high-strength insulating material, by means of a metal current lead pipe fixed in a cylindrical electrostatic screen, characterized in that the walls of the insulating cylinder are made of high-strength insulating material, at least one through hole.

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