RU2834455C1 - Arrester with multi-electrode system - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to lightning arresters for elements of electrical equipment or power transmission lines. Arrester comprises an insulating body made using a dielectric, and two electrodes, mechanically connected to the insulating body and arranged so that to enable formation, under the influence of lightning overvoltage, electric discharge between electrodes in a chamber located inside the insulating body and having an outlet or outputs to the surface of the insulating body. In the chamber there is a multi-electrode system (MES) consisting of alternating insulating and conducting bodies, between which discharges occur under the effect of overvoltage, which contribute to the development of a discharge between the electrodes.

EFFECT: increased strength of discharger, efficiency and reliability of its operation.

8 cl, 4 dwg

Description

Field of technology to which the invention relates

The invention relates to arresters for protection against overvoltages, such as lightning, electrical installations, high-voltage power lines and electrical networks. The invention also relates to high-voltage power lines that have elements equipped with such arresters.

State of the art

Lightning discharges are one of the most dangerous phenomena for the operation of high-voltage power lines. During lightning overvoltage, the air gap between the current-carrying element of the power line and the grounded element is blocked. After the end of the lightning overvoltage impulse, this blockage, under the action of industrial frequency voltage applied to the current-carrying element, turns into an industrial frequency power arc.

A surge arrester is known for limiting overvoltage on a power transmission line based on a protective air spark gap formed between two metal rods (see High Voltage Engineering / Ed. D.V. Razevig - M: Energiya, 1976, p. 285). One of the rods of the known surge arrester is connected to the high-voltage wire of the line, and the second - to a grounded structure, for example, to the body of a power transmission line support. When an overvoltage occurs, the spark gap breaks down, the lightning overvoltage current is diverted to the ground, and the voltage on the device drops sharply. In this way, the lightning current is diverted and the overvoltage is limited. However, the arc-quenching capacity of a single gap is insignificant, so that after the overvoltage has ended, the accompanying current continues to flow along the arc of the spark gap. Therefore, the switch must come into operation and break the circuit, which is highly undesirable for consumers receiving electricity from this line.

As a solution to the problem of the formation of a power arc during lightning overvoltage, in the international application WO 2010082861 a lightning arrester for lightning protection of electrical equipment or a power transmission line was proposed, comprising an insulating body made of a solid dielectric, two main electrodes mechanically connected to the insulating body, and two or more intermediate electrodes made with the possibility of forming a discharge (for example, a streamer) between each of the main electrodes and the intermediate electrode adjacent to it and between adjacent intermediate electrodes, wherein the adjacent electrodes are located between the main electrodes with a mutual displacement, at least along the longitudinal axis of the insulating body.

When such a multi-chamber arrester is exposed to a lightning surge voltage pulse, electrical discharges break through the gaps between the electrodes. Due to the fact that the discharges between the intermediate electrodes occur inside the chambers, the volumes of which are very small, when the channel expands, high gas pressure is created, under the action of which the spark discharge channels between the electrodes move to the surface of the insulating body and are then blown out into the surrounding air.

Due to the resulting blowing and lengthening of the channels between the electrodes, the discharge channels cool down, the total resistance of all channels increases, i.e. the total resistance of the arrester increases, and the lightning surge current is limited. The lightning surge current is diverted through the support into the ground, and the accompanying current of industrial frequency flows after it. When the current passes through zero, the arc goes out, and the power transmission line continues to operate without interruption.

This principle of operation of a multi-chamber arrester is quite effective, since the arrester design is simple, reliable and inexpensive. At the same time, the above-described arrester has such a disadvantage as insufficient mechanical strength at high current pulses flowing through the discharge chambers, during direct lightning strikes in the power transmission line. Arrester ruptures often occur along the surface of the connection of the two halves obtained during its manufacture in two stages. In addition, due to the relatively small size of the electrodes located inside the insulating body, they burn out when the arrester is triggered, and the rubber adhesion to the electrodes is lost, which also leads to arrester ruptures.

The closest analogue of the present invention can be chosen as a so-called tubular arrester for limiting overvoltages on a power transmission line (see High Voltage Engineering / Ed. D.V. Razevig - M: Energiya, 1976, p. 287). The arrester is based on a tube made of insulating gas-generating material. One end of the tube is plugged with a metal cover, on which an internal rod electrode is fixed. At the open end of the tube there is an electrode in the form of a ring. The gap between the rod and ring electrodes is called the internal, or arc-quenching gap. One of the electrodes is connected to the ground, and the second is connected to the power transmission line wire through an external spark gap.

During lightning overvoltage, both gaps break down, and the pulse current is diverted to the ground. After the pulse ends, the accompanying current continues to flow through the arrester, and the spark channel turns into an arc channel. Under the influence of the high temperature of the AC arc channel, an intensive release of gas occurs in the tube, and the pressure increases greatly. The gases, rushing to the open end of the tube, create a longitudinal blow, due to which the arc is extinguished at the first passage of the current through the zero value.

As a result of repeated operation of the arrester, the discharge chamber of the tube is developed. The arrester becomes inoperative and is subject to replacement, which requires high operating costs.

Disclosure of invention

The objective of the invention is to reduce the voltage level at which discharges occur in the arrester, while maintaining increased mechanical strength and durability of the arrester.

The problem is solved using a spark gap having an insulating body, two electrodes mechanically connected to the insulating body, and a discharge chamber located inside the insulating body between the electrodes and having an outlet or outlets on the surface of the insulating body.

A distinctive feature of the invention is that a multi-electrode system (MES) consisting of alternating insulating and conducting elements is located in the insulating body. The elements are installed with the possibility of sequentially forming discharges between the electrode and the conducting element, between the conducting elements and between the conducting element and the electrode when exposed to overvoltage. The discharge chamber is formed by cutouts in the insulating and conducting elements.

The insulating and conducting elements may be made in the form of plates. The insulating and conducting elements preferably have the same transverse shape and size. In the preferred embodiment, the insulating and conducting elements are made in the form of washers.

The insulating body is preferably made in the form of a tube, in particular using a dielectric. The electrodes in the preferred embodiment are made in the form of conductive cups and are fixed at the ends of the insulating body. Between the bottoms of the cups and the conductive and insulating elements of the multi-electrode system, cavities can be made that act as pressure chambers. In the middle part of the multi-electrode system, an intermediate tube can be installed that acts as a pressure chamber.

The technical result of the present invention is to ensure strength at a reduced discharge voltage. These properties, forming the technical result, are achieved simultaneously, which is a significant technical complexity, successfully overcome by the present invention. In particular, the reduction of the discharge voltage is ensured by using a multi-electrode system, and the strength is ensured by placing the multi-electrode system inside the insulating body. The placement of the MES in the insulating body becomes possible due to the fact that it consists of alternating conductive and insulating elements, provided with cutouts so that they form a discharge chamber. The presence of discharge chamber outlets outside the insulating body allows excess pressure from the discharge to escape, which also ensures the strength of the arrester, which cannot be destroyed when passing through the discharge.

The presented design also ensures the compactness of the arrester, since the multi-electrode system is a dense package of alternating conductive and insulating elements placed inside the insulating body.

Brief description of the drawings

Fig. 1 shows a variant of the arc-extinguishing module of the arrester based on an insulating tube with metal cups with axial holes fixed at the ends, wherein the insulating tube is filled with alternating metal and insulating washers or tubes.

Fig. 2 shows a variant of the arc-extinguishing module according to Fig. 1, but containing end pressure chambers.

Fig. 3 shows a variant of the arc-extinguishing module according to Fig. 1, but containing a central pressure chamber.

Fig. 4 shows a diagram of the installation of arc-extinguishing modules according to Fig. 1, 2 and 3 along the perimeter of an insulating part, for example an insulator rib.

LIST OF POSITIONS

1. Insulating tube;

2. Metal washers;

3. Insulating washers;

4. Metal cups;

5. Discharge channel

6. Discharge chamber;

7. Plasma exhausts;

8. End pressure chambers;

9. Exhaust ducts;

10. Central pressure chamber;

11. Metal tube;

12. Insulating piece;

13. Insulating rod;

14. Insulation ring containing modules;

15. Lead electrodes.

Implementation of the invention

The present invention will now be described with reference to the accompanying drawings and particular embodiments. Such a description is given for the purpose of explaining the invention using particular examples and is not intended to limit the scope of protection of the present invention, as defined by the claims. At the same time, if necessary, the claims may include features from the description for the purpose of more accurately defining the scope of protection.

The arrester according to the invention has an insulating body 1, two electrodes 4 mechanically connected to the insulating body 1, and a discharge chamber 6 located inside the insulating body 1 between the electrodes 4 and having an outlet or outlets (9 in Figs. 2 and 3) on the surface of the insulating body 1.

The insulating body 1 shown in the figures is essentially the arrester body and is made using a dielectric material, preferably one with high strength. For example, these may be polymers or other materials used in electrical engineering.

Electrodes 2 in the preferred embodiment are made in the form of conductive cups and are fixed at the ends of the insulating body. The electrodes can be made using metal, for example, copper, aluminum, steel and their alloys or others. The strength of the fastening of electrodes 2 in the form of cups on the insulating body 1 is ensured by the side walls of the cups and their pressing to the insulating body, for example, by gluing, crimping or threaded connection. The bottoms of the cups ensure retention of the multi-electrode system described below inside the insulating body.

In the insulating body 1 of the arrester according to the present invention, a multi-electrode system (MES) is located, consisting of alternating insulating and conducting elements 2 and 3. Elements 2 and 3 are installed with the possibility of sequentially forming discharges between electrode 4 and conducting element 2, between conducting elements 2 (through/above insulating elements 3) and between conducting element 2 and electrode 4 when exposed to overvoltage. Discharge chamber 6 is formed by cutouts in insulating and conducting elements 2 and 3. In the figures, the cutouts are made in the center of insulating and conducting elements 2 and 3, which are, in fact, washers.

Conductive elements can be made of metal (such as copper, aluminum, steel and their alloys or others) or carbon. Dielectric elements can be made of any dielectric materials used in electrical engineering, such as polymers.

The insulating and conducting elements are preferably made in the form of plates so that they can be tightly pressed against each other and thus provide a dense package of the MES. The insulating and conducting elements preferably have the same transverse shape and size. For example, the elements can have a square, rectangular or round shape. In the preferred embodiment shown in the figures, the insulating and conducting elements are made in the form of washers having round openings (cutouts) in the center. However, in other embodiments, the cutouts in the conducting and dielectric elements can be made in other places, for example, from the edges. It is preferable that the cutouts in the elements are in the same places to form a single discharge chamber when assembling the elements in the MES so that the discharge products can be removed from the discharge chamber through one or two openings.

Between the bottoms of the cups 4 and the conductive and insulating elements 2 and 3 of the multi-electrode system, cavities 8 can be formed that act as pressure chambers, as shown in Fig. 2. In the middle part of the multi-electrode system, an intermediate tube 11 can be installed that acts as a pressure chamber 10, as shown in Fig. 3.

To manufacture the arrester, first assemble the multi-electrode system by assembling alternating insulating and conducting elements 2 and 3 into a package (column), placing the MES in the insulating body 1 and securing the electrodes 2 to the ends of the insulating body. One of the electrodes 2 can be secured to the insulating body 1 before placing the MES in it.

Fig. 1-3 shows variants of the implementation of arresters with multi-electrode systems (MES) located inside a durable insulating tube 1. The MES is a set of alternating metal 2 and insulating 3 washers (or tubes).

At the ends of the tubes 1, metal cups 4 are installed. When overvoltage (U-0) is applied to cups 4, a cascade discharge occurs between metal washers 2 inside insulating washers 3, then with an increase in current, a single through channel 5 is formed, connecting both cups 4. With a further increase in current, the diameter of the channel tends to increase, but it is limited by the diameter of a single through discharge chamber 6 passing through washers 2 and 3. The pressure inside the discharge chamber 6 increases sharply, and the discharge channel 5 is blown out in both directions in the form of plasma exhausts 7. As a result of very rapid movement in cold air, plasma 7 and channel 6 cool down, lose their conductivity, and the discharge goes out.

Fig. 2 shows a variant of the spark gap, which differs from the spark gap in Fig. 1 in that it has end pressure chambers 8, made inside the cups 4. In addition, exhaust channels 9 are made, which pass through the side surfaces of the cups 4 and through the insulating tube 1 to the discharge chamber 6. In this way, the direction of the plasma exhaust is ensured not along the axis of the module, as in the module in Fig. 1, but in a perpendicular direction.

When the discharge develops inside the discharge chamber 6, high pressure is also created in the pressure chambers 8. After the plasma 7 escapes from the channels 9, low pressure is created in them. Cold, non-ionized air from the pressure chambers 8 enters the channels 9 and helps to cool the plasma in them and quench the discharge.

Fig. 3 shows a variant of the discharger, which differs from the discharger in Fig. 2 in that it has a pressure chamber 10, made in the middle part of the MES by installing a metal tube 11 between two metal washers 2. In this variant, after the plasma 12 has escaped, cold air from the pressure chamber 10 spreads to both sides of the discharge chamber 6, and helps to extinguish the discharge.

In order to increase the quenching voltage, the arresters can be connected in series. Fig. 4 shows a diagram of the installation of arresters according to Figs. 1, 2 and 3 along the perimeter of an insulating part, for example, an insulator rib 12 installed on an insulating support rod 13. An insulating ring 14 is installed along the perimeter of the insulating part 12, into which arresters are mounted, for example according to Fig. 3. The ring 14 can be made, for example, of silicone rubber. The arresters are connected in series by means of contact between the cups 4. Taps 15 are connected to the outer cups 4 of the outer modules, through which the arrester is connected to the object affected by the overvoltage, for example, to the power transmission line wire and grounding. When exposed to overvoltage, the arresters operate and provide its limitation.

Claims (8)

1. A spark gap comprising an insulating body, two electrodes mechanically connected to the insulating body, and a discharge chamber located inside the insulating body between the electrodes and having an outlet or outlets on the surface of the insulating body, characterized in that a multi-electrode system is located in the insulating body, consisting of alternating insulating and conductive elements installed with the possibility of sequentially forming discharges between the electrode and the conductive element, between the conductive elements, and between the conductive element and the electrode when exposed to overvoltage, wherein the discharge chamber is formed by cutouts in the insulating and conductive elements. 2. A spark gap according to item 1, characterized in that the insulating and conductive elements are made in the form of plates. 3. A spark gap according to item 1, characterized in that the insulating and conductive elements are made in the form of washers. 4. The arrester according to item 1, characterized in that the insulating and conductive elements have the same transverse shape and size. 5. A spark gap according to item 1, characterized in that the insulating body is made in the form of a tube. 6. A spark gap according to item 1, characterized in that the electrodes are made in the form of conductive cups and are fixed at the ends of the insulating body. 7. A discharger according to item 6, characterized in that between the bottoms of the cups and the conductive and insulating elements of the multi-electrode system there are cavities that act as pressure chambers. 8. A spark gap according to item 6, characterized in that an intermediate tube is installed in the middle part of the multi-electrode system, which acts as a pressure chamber.