RU2510651C1 - Arrester with guide strips for protection of electric equipment from overvoltage at lightning and insulator of power line equipped with such arrester - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention presents arrester with guide strips for protection of electric equipment or power line that contains insulating body made of solid dielectric, two main electrodes connected mechanically with insulating body and two or more intermediate electrodes placed between the main electrodes with mutual displacement at least along longitudinal axis of the insulating body; they can be formed between the main and intermediate electrodes of streamer discharge. Intermediate electrodes are placed inside the insulating body and are separated from its surface by insulation layer, at that between the first and second adjoining electrodes there are exposed discharge chambers. At least three discharge chambers are equipped with guide strips made of insulating material fixed to external surface of the insulating body and installed to prevent spreading of plasma cloud formed inside chambers during discharge from one discharge chamber towards the neighbouring discharge chamber by means of plasma cloud streaming to outside air.

EFFECT: improving reliability.

9 cl, 5 dwg

Description

FIELD OF THE INVENTION

The present invention relates to arresters for protecting electrical equipment from lightning surges. Such devices can protect, for example, high-voltage installations, insulators and other elements of high-voltage power lines, as well as electrical equipment.

State of the art

Known arrester to limit overvoltages on the power line in the form of a protective spark gap, consisting of two metal rods and an air gap between them (see Technique of high voltage / Ed. By D.V. Rasevig. - M .: Energy, 1976, p. 285). One of the rods of the known device is connected to the high-voltage wire of the line, and the second to the grounded structure, for example, to the body of the support of the power line. During overvoltage, the spark gap breaks through, the lightning overvoltage current is discharged to the ground and the voltage on the device drops sharply. Thus, lightning current is removed and overvoltage is limited. However, the arcing ability of a single gap is insignificant, so that after the overvoltage over the arc of the spark gap the accompanying current continues to flow. Therefore, the circuit breaker must come into operation and break the circuit, which is highly undesirable for consumers receiving electricity from a given line.

Also known is a spark gap with the so-called multi-electrode system (MES) (patent No. 2299508 from 05.20.2007). At these arresters between the first and second main electrodes on the insulating body there are many small intermediate electrodes. To reduce the discharge voltage inside the insulating body, along its axis, an additional rod electrode is installed, electrically connected to one of the main electrodes.

Due to the division of the interval between the main electrodes into many spark gaps, this spark gap has a higher arc suppression ability than devices with one or with a small number of discharge gaps.

Nevertheless, its arc suppression ability is not large enough, which limits its scope only to lightning protection of VL 6-10. It is difficult to use for lightning protection of overhead lines of higher voltage classes, because the number of intermediate electrodes and the dimensions of the arrester become too large.

As the closest analogue of the present invention, a spark gap with the so-called multicamera system (MKS) can be selected (patent No. 2346368 from 02.10.2009). In the arrester for lightning protection of electrical components or power lines, containing an insulating body made of a solid dielectric, two main electrodes mechanically connected to the insulating body, and m intermediate electrodes (m≥2) located between the main electrodes with a mutual offset of at least , along the longitudinal axis of the insulating body and configured to form between adjacent main and intermediate electrodes of the streamer discharge, according to the invention, intermediate electrodes The odes are located inside the insulating body and are separated from its surface by an insulation layer, and discharge chambers extending to the surface of the insulating body are made between adjacent electrodes, the width of which in the zone of formation of the streamer discharge is less than the calculated diameter of the specified discharge, and the thickness of the specified insulation layer is chosen to exceed the calculated diameter of the specified discharge.

Due to the inclusion of many spark discharge chambers between the main electrodes, this spark gap has a higher arc suppression ability than devices with one, two, or even with a large number of open discharge gaps.

The specified arrester reliably works at relatively small pulse currents flowing through it, for example, when lightning strikes into a support or a cable and back overlaps from the support to the wire. With direct lightning strikes with significant currents, a breakdown between plasma clouds blown from the discharge chambers is possible, i.e. possibly arcing outside the arrester in the open air. The arc burns steadily, which leads to an emergency shutdown of electrical equipment.

Also known is an insulator equipped with the specified spark gap (patent No. 2378725 from 01/10/2010). A multi-chamber system (ISS) is strengthened around the perimeter of an insulating body, such as a plate insulator. The ends of the ISS are equipped with lead electrodes. Under the influence of overvoltage on the supply electrodes of the ISS, it triggers and the arrester damps the accompanying current. This insulator-arrester has the same drawback as the above-described arrester with the ISS - with large current pulses corresponding to a direct lightning strike into the wire, an arc can form outside the arrester.

Disclosure of invention

Accordingly, the task that the present invention solves is the creation of a spark gap having a low cost in the manufacture and operation of a high reliability. This will make it possible to use the arrester according to the invention for lightning protection of overhead lines from direct lightning strikes and to abandon the lightning protection cable. Another problem solved by the present invention is to create an insulator-discharger for a power line with high arc suppression ability.

This problem is solved in that in the arrester for lightning protection of electrical equipment elements or power lines containing an insulating body made of a solid dielectric, two main electrodes mechanically connected to the insulating body, and two or more intermediate electrodes located between the main electrodes with mutual displacement, at least along the longitudinal axis of the insulating body and configured to form a streamer discharge between adjacent main and intermediate electrodes, p When in use, the intermediate electrode disposed within the insulating body and separated from the surface of the insulation layer, wherein between adjacent first and second electrodes formed on the surface facing the insulating body discharge chambers.

A distinctive feature of the present invention is that at least three discharge chambers are provided with guides made of insulating material attached to the outer surface of the insulating body and installed with the possibility of preventing the spread of a cloud of plasma formed inside the chambers during the discharge from the discharge chamber to the side neighboring discharge chamber by directing a cloud of plasma into the external air environment.

The distances between the walls of the guides installed on opposite sides of the exits of the discharge chambers to the surface of the insulating body are mainly not less than the width of the discharge chambers. The length of the guides is predominantly greater than the depth of the discharge chambers.

The guides can be made in the form of flat plates. In another embodiment, the guides can be made in the form of semicircular in terms of walls.

A gap of 0.5-10 mm wide may be provided between the edges of said semicircular walls in terms of walls, however, the edges of semicircular in terms of walls, at least on one side, can be interconnected. In any of the above variants of the arrester, the walls of the guides at the base facing the surface of the insulating body can be made thicker than at the edges directed outward.

The objective of the present invention is also solved by using a high-voltage insulator for mounting, as a single insulator or as part of a column or a string of insulators, a high-voltage wire in an electrical installation or on a transmission line containing an insulating part and fittings in the form of first and second reinforcement elements installed at its ends, moreover, the first armature element is made with the possibility of connection, directly or by means of a mounting device, with a high-voltage wire or with a second element a the valve of the previous high-voltage insulator of the indicated column or garland, and the second reinforcement element is made with the possibility of connection with the support or with the first reinforcement element of the subsequent high-voltage insulator of the specified column or garland. A distinctive feature of the insulator is that it contains a spark gap according to any of the above options, installed with the possibility of forming, under the influence of lightning overvoltage, an electric discharge between the first element of the insulator reinforcement and at least one adjacent spark gap electrode, as well as the second element reinforcement of the insulator and at least one adjacent spark gap electrode.

Thanks to the use of guides, it is possible to achieve such a technical result as reducing the likelihood of combining individual electrical discharges into one, thereby increasing the service life of the arrester and improving the protection of electrical equipment. Thus, the achieved technical result is to increase the reliability of lightning arresters.

Brief Description of the Drawings

The invention is illustrated by drawings, where:

figure 1 shows an embodiment of a spark gap with a round insulating body and flat guide walls in cross section in front view;

in Fig.2 the arrester of Fig.1 is a top view;

figure 3 shows an embodiment of a spark gap with a round insulating body and semicircular guide walls in cross section in front view;

in Fig.4 the arrester in Fig.3 is presented in a top view;

figure 5 illustrates an embodiment of an insulator with a spark gap according to the invention installed around the perimeter of the insulating body.

The implementation of the invention

As shown in figures 1, 2, the arrester for lightning protection of electrical components or power lines according to the invention contains a circular insulating body 1 made of a solid dielectric, for example rubber. At the ends of the insulating body 1, the first 2 and second 3 main electrodes are installed, which due to this installation are mechanically connected with the insulating body. Inside the insulating body 1, m intermediate adjacent electrodes 4 are installed. The minimum value of m is two, while the optimal number of intermediate electrodes is selected taking into account the specific form of their execution, the calculated value of the overvoltage and other conditions of their operation. In this embodiment, the intermediate electrodes 4 are made in the form of segments of metal cylinders installed with the formation of spark gaps between them. To this end, the intermediate electrodes are predominantly offset relative to each other along the longitudinal axis of the arrester (connecting the main electrodes 2, 3), however, there may be other configurations of the arrangement of electrodes that allow the intermediate electrodes to form spark gaps between themselves, for example, by displacement along the other axis or by in such a way that it is impossible to select the axis along which the electrodes are displaced.

As already indicated, between adjacent intermediate electrodes 4 there is a spark air gap g with a width a of the discharge chamber, which is connected to the discharge chamber 6, which faces the surface of the insulating body 1, on the surface of which guides are fixed, mainly made in the form of walls of one form or another, the size of which in the transverse axis of the spark gap direction is predominantly larger than the width of the discharge chamber.

When protecting high-voltage installations or power lines, the arrester is connected with one main electrode (for example, the first main electrode 2) to a high-voltage power element, for example, a wire (directly or through the spark gap), and another, respectively, the second, main electrode 3 (directly or through spark discharge gap) to the ground.

When an overvoltage pulse is applied to the spark gap, the discharge develops from the first main electrode 2 towards the second main electrode 3, sequentially punching the gaps between the intermediate adjacent electrodes 4. In the process of formation and development of the spark channel 5, it expands with supersonic speed. Since the volumes of the discharge spark chambers 6 between adjacent electrodes 4 are very small, high pressure is created under the influence of which the channels of spark discharges between adjacent electrodes move to the surface of the insulating body and then air out into the surrounding spark gap in the form of clouds of conducting plasma 8. Due to the arising blast and elongation of channels between adjacent electrodes, the total resistance of all channels increases, i.e. the total resistance of the arrester increases, and the impulse current of lightning overvoltage is limited. At the end of the lightning overvoltage pulse, an industrial frequency voltage remains applied to the arrester. Due to the high resistance of the arrester, and due to the fact that the channel is divided into many elementary channels between adjacent electrodes, the discharge cannot independently exist and goes out. However, there is a danger of electrical breakdown between the clouds of the conducting plasma 8 and the development of an arc discharge outside the spark gap. This leads to a short circuit and shutdown of electrical equipment.

For the separation of plasma clouds and the formation of narrower, not merging with each other plasma clouds 8 are guides 7 according to the invention. The guides 7 are made of insulating material, for example silicone rubber, and are fixed to the surface of the insulating body 1. They can be formed, for example, by pressing the insulating body 1 and be monolithic with it. The guides 7 are installed with the possibility of preventing the spread of the plasma cloud formed inside the chambers during the discharge from the discharge chamber towards the adjacent discharge chamber by directing the plasma cloud into the external air environment. One common guide may be installed between the discharge chambers, or separate guides for each chamber can be installed, for example, if the chambers are separated by a considerable distance between themselves, as shown, for example, in FIG. 5.

The guides shown in FIGS. 1 and 2 are made in the form of flat plates mounted perpendicular to the axis of the arrester, however, the plates can also be located at an angle to the specified axis, provided that the plasma clouds do not propagate towards adjacent discharge chambers.

As shown in FIGS. 3 and 4, to effectively prevent the plasma clouds 8 from interconnecting, the guides 7 can be made semicircular in plan, that is, in the form of half-cylinders. Between the edges of the guides 7, a slit 0.5 to 10 mm wide can be formed, as shown in FIGS. 3 and 4, however, the edges of the semicircular walls, at least on one side in another embodiment, can be interconnected.

Figure 5 shows the arrester of figure 3, 4, installed around the perimeter of the ribs of the polymer insulator containing the insulating body 9, the upper terminal 10, the lower terminal 11 and the insulation rod 12. In some cases, for example to prevent water droplets from falling into the rain discharge chambers, the upper edges of the plates can be partially interconnected. It is also possible that plates with fully closed upper and lower edges, i.e. in the form of pipe segments.

In the above-described embodiments, the distances between the walls of the guides mounted on opposite sides of the outputs of the discharge chambers to the surface of the insulating body are advantageously not less than the width of the discharge chambers. The length of the guides is predominantly greater than the depth of the discharge chambers. The guide walls at the base facing the surface of the insulating body can be made thicker than at the edges directed outward.

The performance of the spark gap according to the invention is confirmed by experimental verification. For this purpose, a spark gap was made and installed around the perimeter of a single rib of a polymer insulator. The main parameters of the arrester are as follows (see figures 1-4):

- the camera is made in the form of a gap with a discharge gap of length g = 10 mm, a width of a = 2 mm and a depth of b = 15 mm;

- the guides are made semicircular in plan according to figure 3, 4 with a height of h = 20 mm and a slit width of Δ = 2 mm;

- adjacent intermediate electrodes are made of pieces of metal cylinders with a diameter of 6 mm;

- the number of cameras was 8 pcs .;

The tests showed that when tested with current pulses with a maximum value of 30 kA and a duration of 55 μs, the spark gap reliably extinguishes the pulse current without an accompanying mains current at a network voltage of 6 kV _d (effective value).

Moreover, the arrester maintains its integrity and performance when exposed to at least 10 pulses. These parameters are sufficient for the formation of polymer insulators - arresters for voltages of 110, 220 kV and higher and, accordingly, for lightning protection of overhead lines of the indicated voltage classes.

It should be noted that the spark gap without guides 7 extinguishes the pulse current without an accompanying mains current only at a voltage of 3 kV _d (effective value), i.e. at about half the voltage than with rails. At higher voltage, a breakdown occurs between plasma clouds flying out of the discharge chambers, which is eliminated when installing the guides according to the invention. Thus, the scope and reliability of the spark gap of the present invention is significantly increased.

The options and modifications of the spark gap of the invention and insulators - arresters constructed using such arresters described in this description are given only to explain their design and operating principles. Specialists in the art should understand that there may be deviations from the above examples, which are also covered by the claims.

Claims (9)

1. Arrester for lightning protection of electrical equipment or power lines, containing an insulating body made of a solid dielectric, two main electrodes mechanically connected to the insulating body, and two or more intermediate electrodes located between the main electrodes with mutual displacement, at least along the longitudinal axis of the insulating body and configured to form between adjacent main and intermediate electrodes of an electric discharge, as well as intermediate electrodes, located inside the insulating body and separated from its surface by an insulation layer, while between adjacent electrodes discharge chambers extending to the surface of the insulating body are made, characterized in that at least three discharge chambers are provided with guides made of insulating material attached to the outer surface insulating body and installed with the possibility of preventing the spread of a cloud of plasma formed inside the chambers during the discharge from the discharge chamber towards the neighboring Operating capacity chamber by means of a plasma cloud in the external air environment. 2. The arrester according to claim 1, characterized in that the distances between the walls of the guides installed on opposite sides of the exits of the discharge chambers to the surface of the insulating body are not less than the width of the discharge chambers. 3. The arrester according to claim 1, characterized in that the length of the guides is greater than the depth of the discharge chambers. 4. The arrester according to claim 1, characterized in that the guides are made in the form of flat plates. 5. The spark gap according to claim 1, characterized in that the guides are made in the form of walls semicircular in terms of. 6. The arrester according to claim 5, characterized in that between the edges of the semicircular in terms of the walls there is a gap with a width of 0.5-10 mm; 7. The arrester according to claim 5, characterized in that the edges of the walls semicircular in terms of at least one side are interconnected. 8. Arrester according to any one of paragraphs. 1-5, characterized in that the walls of the rails at the base facing the surface of the insulating body are thicker than at the edges directed outward. 9. A high-voltage insulator for fastening, as a single insulator or as part of a column or a string of insulators, a high-voltage wire in an electrical installation or on a power line, containing an insulating part and fittings in the form of first and second fittings installed at its ends, the first fittings being made with the possibility of connecting, directly or by means of a fixing device, to a high-voltage wire or to a second valve element of a previous high-voltage insulator of the decree columns or garlands, and the second reinforcement element is configured to be connected to a support or to the first reinforcement element of a subsequent high-voltage insulator of said column or garland, characterized in that it comprises a spark gap according to any one of paragraphs. 1-8, installed with the possibility of forming, under the influence of lightning overvoltage, an electric discharge between the first element of the insulator reinforcement and at least one adjacent electrode of the spark gap, as well as the second element of the insulator reinforcement and at least one adjacent to it discharger electrode.

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