RU2299508C2 - Current-carrying device for lightning protection of electrical equipment and power transmission lines equipped with such device - Google Patents

Abstract

FIELD: lightning surge protection of various structures and pieces of equipment.

SUBSTANCE: proposed device has insulation body 1 made of solid insulating materials, two main electrodes 2, 3 mechanically coupled with insulation body 1, and intermediate electrodes 5 disposed on insulation body between main electrodes and relatively offset at least on longitudinal axis of insulation body. Preferable design alternate of device has each intermediate electrode 5 made in the form of ring and is provided with pair of projections disposed on opposite butt-end sides of ring and spaced at least 90 deg. apart over their circumference. Insulation body and additional electrode can be made in the form of shielding insulation layer section and wire section, respectively, disposed between main electrodes. First main electrode in this design alternate is made in the form of piercing clamp installed on shielding insulation layer and second main electrode is grounded either directly or through spark gap.

EFFECT: enhanced reliability and simplified mechanical design of lightning surge protective gear.

25 cl, 12 dwg

Description

Technical field

The present invention relates to down conductors for protecting electrical equipment and various structures and structures from lightning surges. Such devices can protect, for example, high-voltage installations, insulators and other elements of high-voltage power lines, electrical equipment, as well as structural elements of radars (especially aircraft) and other structures and devices requiring lightning protection.

State of the art

A current-conducting device is known for limiting overvoltages on a power line in the form of a protective spark gap consisting of two metal rods and an air gap between them (see High Voltage Technique / Edited 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 diverted to the ground and the voltage across the device drops sharply. In this way, thunderstorm 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 switch must come into operation and break the circuit, which is very undesirable for consumers receiving electricity from this line.

A collector is also known, which differs from the one described above in that a third rod intermediate electrode is located between the first and second main electrodes (rods) (see, for example, US patent No. 4665460, 12.05.87, H01T 004/02). Thus, instead of one air spark gap, two such gaps are created. Thanks to this, it was possible to slightly increase the arc-suppressing ability of the collector and to suppress small (of the order of tens of amperes) accompanying currents during single-phase earth faults. However, this device cannot disconnect currents of more than 100 A, which usually occur during two- and three-phase earth faults during lightning overvoltages.

In order to overcome this difficulty, more sophisticated down conductors for protecting power lines based on pulsed spark collectors have been developed (see, for example, US Pat. 001/00).

However, since most of the known down conductors of this purpose are based on the use of a set of nonlinear elements, they have a complex structure and high cost.

An important and rather difficult problem is also the lightning protection of aircraft radars, since a lightning strike causes serious damage to the conductive elements and components of the radar, up to their complete destruction. In addition, with such a shock, as a result of a sharp increase in pressure inside the shell (fairing) of the radar antenna, damage to the structure of the radar, especially its fairing, is possible.

To prevent such a danger, various down conductors have been developed that are installed on the radar fairing (such devices are described, for example, in US Pat. Nos. 4,445,161, 04.24.84, H02H 003/22 and 4583702, 04.22.86, B64D 045/02). Known devices of this type typically use a strip of dielectric material, which is fixed on the outer surface of the fairing (in some known devices, for example, according to US patent No. 4796153, 01/03/89, B64D 045/02; H05F 003/00 there are several such strips) . A single or each such strip carries electrodes mounted on it, for example, square or round in shape, between which a large number of discharge gaps are connected in series.

As the closest analogue of the present invention, a down conductor device for lightning protection of fairings of aircraft radar fairings according to US patent No. 4506311, 03.19.85, H05F 003/00 can be selected. This device also contains a strip of solid dielectric, which performs the function of an insulating body, with which many electrodes are located mechanically connected (by installing on it), located with mutual displacement along the longitudinal axis of the insulating body. The two extreme electrodes serve as the main electrodes, and the rest, located between them, the electrodes are intermediate electrodes. When lightning strikes the specified device, spark gaps between the electrodes overlap and the lightning current flows through the formed channel to the metal body of the aircraft, bypassing the fairing and the electrical equipment located underneath. To reduce the discharge voltage in the analog device, rhomboid-shaped electrodes oriented vertices to each other are used; The uneven arrangement of the intermediate electrodes along the insulating body serves the same purpose. By dividing the interval between the main electrodes into many spark gaps, this downstream device has a higher arc suppression ability than devices with one or with a small number of discharge gaps (see, for example, AS Taev, “Electric arc in low voltage apparatuses,” ed. "Energy", 1965, p. 85). However, as will be explained in the further description, the discharge voltages in the known device are too high, which limits its scope only to the protection of aircraft radars. However, it cannot be used, for example, as a collector to protect power transmission elements from overvoltage.

Disclosure of invention

Accordingly, the problem that the present invention solves is the creation of a reliable and low cost in the production and operation of a collector device characterized by low discharge voltages. This will make it possible to use the device according to the invention for solving a wide range of problems, and, first of all, not only for efficient removal of lightning current while protecting electrical equipment from direct lightning strikes, but also as a lightning current-collecting device capable of extinguishing the accompanying current arc at large, actually encountered in practice values of this current.

Thus, the achieved technical result is to increase the reliability and simplify the design of means of protection against lightning impacts.

Another problem solved by the present invention is to create a power line having reliable lightning protection due to its equipping with reliable and inexpensive current-conducting devices characterized by low discharge voltages.

The first problem was solved mainly by creating a down conductor device for lightning protection of electrical components, power lines, structures or structures containing an insulating body made of a solid dielectric, at least two main electrodes mechanically connected to the insulating body, and m intermediate electrodes, located on the insulating body between the main electrodes with mutual displacement, at least along the longitudinal axis of the insulating body. Moreover, the device according to the invention is characterized in that an additional rod electrode is installed inside the insulating body, along its axis, electrically connected to one of the main electrodes and located opposite at least one of the intermediate electrodes. In addition, the thickness Δ _{i of the} layer of the insulating body between the ith intermediate electrode (i = 1, 2, ... (m) and the main electrode electrically connected to the additional electrode is selected to satisfy the condition

where U _{p, i} is the discharge voltage between the i-th intermediate electrode and the main electrode, electrically connected to the additional electrode; E _CR - breakdown voltage of the insulating material from which the insulating body is made (hereinafter, for greater certainty, the main electrode, which has a higher potential when the discharge current flows through the device, will be called the first main electrode; accordingly, the main electrode, which when the discharge current flows through the device has a low, for example, zero, potential, will be called the second main electrode).

In order to make the most efficient use of the material from which the insulating body is made, in one of the preferred embodiments of the device, the insulation thickness between the additional electrode and the corresponding intermediate electrode is directly related to the distance between this electrode and the main electrode electrically connected to the additional electrode.

In one embodiment of the device, preferred for technological reasons, the insulating body, which is the insulation of the cable section, is U-shaped, and the additional electrode is a core of this cable section, i.e. has a length equal to the length of the insulating body. The first main electrode in this embodiment, it is advisable to perform in the form of a metal tube, covering the insulating body in its curved part. Accordingly, the second main electrode can be mechanically connected to one or both ends of the insulating body and electrically connected to the additional electrode. The intermediate electrodes can be located on one or both shoulders of the insulating body.

Depending on the specific requirements for the quality of lightning protection and on the conditions of use of the device according to the invention, intermediate electrodes of various designs can be used in it. For example, these electrodes can be made in the form of metal plates with rounded edges or pieces of insulated wire. In this case, the line along which the intermediate electrodes are located with mutual displacement can be oriented parallel to the longitudinal axis of the insulating body. However, in embodiments in which the insulating body and the auxiliary electrode have a circular cross-section at least in the area where the intermediate electrodes are installed, it may be appropriate to arrange the intermediate electrodes along a line that has the shape of a spiral covering the surface of the insulating body. In the latter embodiment, it may be especially convenient to fix the intermediate electrodes on a tape of insulating material and fix this tape by spiral winding on the surface of the insulating body.

One of the most effective embodiments of the intermediate electrodes is to give each (or at least one) of them a ring shape and to supply each or a single electrode in the form of a ring with a pair of protrusions located on its opposite end sides. The length of each such protrusion should be less than the distance from the end plane of the ring to the adjacent intermediate electrode. In this case, the protrusions are preferably mutually displaced around the circumference of the ring, preferably 180 °, but at least 90 °. When using two or more intermediate electrodes in the form of rings provided with protrusions, protrusions facing adjacent electrodes on adjacent electrodes are preferably arranged without mutual displacement around the circumference of the ring.

In addition, the rings can be made of resistive material (for example, nichrome), and it is desirable to cover their side surface with a layer of insulation. In this case, it is preferable to cover with a layer of insulation both the surface of the insulating body and the side surface of the rings, with the exception of the protrusions made on them.

In a variant of a collector specially designed to protect electrical equipment and radar radome, the main electrodes and an additional electrode, it is advisable to perform in the form of parallelepipeds. The insulating body in this case has the form of a hollow parallelepiped, the cavity of which corresponds to the shape of an additional electrode, which fills this cavity. The second main electrode in this case is electrically connected to the radar housing and to the additional electrode.

In an embodiment of a collector specifically designed to protect overhead power line (VL) power line elements, at least one first main electrode can be connected directly or through a spark gap to a protected element, and a second main electrode directly or through a spark discharge gap is connected to ground. Moreover, if the overhead line is designed for a voltage of 10 kV, it is recommended that the diameters of the insulating body and the additional electrode be selected with components of 8-60 mm and 3-50 mm, respectively. The distances between the main and intermediate electrodes in this case, it is recommended to choose respectively 600-1000 mm and 1-100 mm components.

The second problem posed by the invention is solved by creating a power line containing supports with insulators, at least one wire under electrical voltage, connected to the insulators by means of fixing devices, and at least one current-conducting device for lightning protection of power line elements. In accordance with the present invention, such a collector for lightning protection of power line elements (and, preferably, each of a plurality of such collectors) is made in the form of a collector of the present invention.

In the event that the live wire of the line is located inside the insulating protective layer, the first main electrode can be made in the form of a biting clip installed on the insulating protective layer and electrically connected to the wire, and the insulating body and the additional electrode, respectively, in the form of a piece of insulating a protective layer and a piece of wire located between the main electrodes.

Alternatively, when at least one fastening device is made in the form of an insulating strapping, the intermediate electrodes of the collector can be made in the form of metal rings mounted on this strapping with mutual displacement along its length. In this embodiment, the second main electrode is located near the line insulator, and the first main electrode is made in the form of a biting clip, electrically connected to a live wire.

According to another embodiment of the construction of the power line, the current-conducting device for lightning protection included in it comprises a length of cable, the insulation of which forms an insulating body, and the metal core is an additional electrode. In the collector there are two first main electrodes, which are made in the form of terminators of the cable segment, as well as clamps, through which the ends of the cable segment are attached to the line wire. The second main electrode is made in this embodiment in the form of a metal tube mounted in the middle of the cable and attached to the support insulator. The intermediate electrodes are made in the form of rings mounted on an insulating body between the first main electrodes and the second main electrode with mutual displacement along the length of the insulating body. An auxiliary electrode is mounted on the support for forming, together with the second main electrode, a spark discharge gap.

Brief Description of the Drawings

The invention is illustrated by drawings, where:

on figa given a schematic representation of the device according to the invention in front view;

on figb the device of figure 1 is presented in cross section, in side view;

Fig. 1c shows a circuit diagram of a device according to the invention;

figure 2 explains the voltage distribution between the electrodes of the device;

figure 3 shows an embodiment of a device with intermediate electrodes arranged in a spiral;

figure 4 illustrates a variant of the device with intermediate electrodes from pieces of insulated wire;

figure 5, in cross section, shows a variant of the device with intermediate electrodes in the form of rings;

Fig.6, in cross section, shows a variant of the device, similar to the variant of Fig.5, but with an insulation layer covering the insulating body and the intermediate electrodes in the form of rings;

7, in cross section, shows a variant of the device with an insulating body and an additional electrode made in the form of a loop;

Fig. 8 illustrates an embodiment of an overhead power transmission line (VL) according to the invention with a collector constructed using a protected line wire;

Fig. 9 illustrates an embodiment of an overhead line according to the invention with a collector constructed using an insulating harness of a protected overhead line;

figure 10 shows, at various scales and in a perspective image, partial types of OHL 10 kV, which includes a collector device according to the invention.

The implementation of the invention

As shown in figa, 1b, the down conductor device for lightning protection according to the invention contains an elongated insulating body 1 made of a solid dielectric, for example polyethylene. 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. On the insulating body 1 are fixed m intermediate electrodes 5. The minimum value of m is equal to unity, while the optimal number of intermediate electrodes is selected taking into account the specific form of their implementation, the calculated value of the overvoltage and other conditions of their work. In this embodiment of the device, the intermediate electrodes 5 are made in the form of 7 metal plates having rounded edges and offset one relative to the other along the longitudinal axis of the device (connecting the main electrodes 2, 3). As can be seen from fig.1b, inside the insulating body 1 there is an additional electrode 6 in the form of a metal rod, which is electrically connected to one of the main electrodes (in the embodiment of figa, 1b - with the second main electrode 3). As shown in figb, the length of the additional electrode 6, it is advisable to choose such that it is located opposite all the intermediate electrodes 5. However, the beneficial effect created by the additional electrode will be significant in the case when its length is at least half the distance between the main electrodes 2, 3. In any case, in order to achieve a positive effect, the minimum length of the additional electrode 6 must be such that it is located opposite at least one (in FIG. 1 b lower) weft electrode.

The thickness of the insulation layer, i.e. the thickness Δ _{i of the} insulating body 1 between the ith intermediate electrode 5 (i = 1, 2, ... m), the main electrode electrically connected to the additional electrode 6 (in this case, the second main electrode 3), is determined from the condition

where U _{p, i} is the discharge voltage between the i-th intermediate electrode and the main electrode, electrically connected to the additional electrode 6; E _CR - breakdown strength of the insulating material from which the insulating body 1 is made.

In the case where the collector according to the invention is used for lightning protection of a radar (mainly aircraft), i.e. when the elements to be protected are the electric equipment of the radar and the fairing of its antenna, the device according to the invention (as well as known devices of a similar purpose) is fixed to the surface of the fairing using fastening means not shown in FIG. The main electrode, which is electrically connected to the additional electrode 6 (in the embodiment shown in FIG. 1, the second main electrode 3), is also connected to the radar housing and, in the process of operation of the device, acts as an electrode having a low (zero potential). Moreover, the longitudinal axis of the device according to the invention is preferably oriented parallel to the axis of the fairing. With regard to this use of the device according to the invention, it is desirable to give the cross-section of the additional electrode 6 a rectangular shape. Accordingly, it is advisable to give the main electrodes 2, 3 a shape close to the shape of a parallelepiped, and the insulating body 1 - a shape close to the shape of a hollow parallelepiped, the cavity of which is filled with an additional electrode 6.

In other applications, for example, when protecting high-voltage installations or power lines, the collector is connected by one main electrode (for example, the first main electrode 2) to a high-voltage power element, for example, to wire 4 (directly or through a spark discharge gap), and the other, respectively, the second , the main electrode 3 (directly or through the spark discharge gap) to the ground.

From the circuit diagram of the collector (shown in Fig.1c) it is clear that with the described connection of the main electrodes 2, 3 in the case of exposure to the device overvoltage pulse (corresponding to voltage U), a spark discharge gap first breaks between the high-voltage wire 4 of the protected overhead line and the first the main electrode 2, and then the discharge develops from the first main electrode 2 towards the second main electrode 3, sequentially punching the gaps between the 5 electrodes.

Благодаря относительно большой площади поверхности промежуточного электрода 5, обращенной в сторону дополнительного электрода 2, а также вследствие того, что диэлектрическая проницаемость твердого диэлектрика ε значительно выше, чем диэлектрическая проницаемость воздуха ε₀ (обычно ε/ε₀≈2÷3), емкость промежуточного электрода 5 на дополнительный электрод 6 (т.е. емкость этого промежуточного электрода на землю) существенно больше, чем его емкость на основной электрод 2, т.е. С₀>C₁ и, соответственно, C₁/C₀<1.Figure 2 shows a detailed fragment of the circuit diagram of figure 1B, containing the first main electrode 2, the intermediate electrode 5 closest to it, and the additional electrode 6. There is a capacitance C ₁ between the electrodes 2 and 5, and a capacitance between the electrodes 5 and 6 C ₀ . These capacitances are connected in series, and when exposed to an overvoltage pulse, voltage U is applied to them. Voltage U ₁ on capacitances C ₁ , i.e. the voltage at the spark gap between the first main electrode 2 and the intermediate electrode 5 closest to it, in relative units, is determined by the formula:

Due to the relatively large surface area of the intermediate electrode 5 facing the side of the additional electrode 2, and also because the dielectric constant of the solid dielectric ε is much higher than the dielectric constant of air ε ₀ (usually ε / ε ₀ ≈ 2 ÷ 3), the capacity of the intermediate electrode 5 to the additional electrode 6 (i.e., the capacity of this intermediate electrode to earth) is significantly larger than its capacity to the main electrode 2, i.e. C ₀ > C ₁ and, accordingly, C ₁ / C ₀ <1.

When the values of the ratio C ₁ / C ₀ lying in the range C ₁ / C ₀ = 0.1 ÷ 0.9, the voltage U ₁ is in the range U ₁ = (0.53 ÷ 0.91) U. Therefore, when the voltage U is applied to the collector, the main part (at least more than half) of the voltage drop falls on the first spark gap between the electrodes 2 and 5. Under the influence of this voltage U _1, this gap breaks through, and the intermediate electrode 5 is the first to the main electrode 2 acquires the potential of the main electrode 2, and the next intermediate electrode 5 adjacent to the first intermediate electrode acquires the potential U ₀ . Further, the physical picture of the breakdown of the spark gap is repeated. Thus, cascading, i.e. sequential overlapping of the gaps between the intermediate electrodes 5 with the formation of an arc discharge (arc) 7. Due to the cascade of operation of the discharge gaps, the required low discharge voltage of the operation of the collector is provided.

It should be noted that the circuit diagram shown in FIGS. 1c and 2 is also applicable to the closest analogue of the invention discussed above. However, in this case, C ₀ is the capacitance of the intermediate electrode 5 to the ground, which is at a significantly greater (tens and hundreds of times) distance from the intermediate electrode 5 than the distance between adjacent intermediate electrodes 5, which determines the capacitance C ₁ between them. Therefore, C ₀ is several times less than C ₁ . For example, when the values of the ratio C ₁ / C ₀ lying in the range C ₁ / C ₀ = 5 ÷ 10, the voltage U ₁ is in the range U ₁ = (0.09 ÷ 0.17) U. Thus, it can be seen that in the prototype, the uneven distribution of voltage across the spark gaps between the intermediate electrodes 5 is significantly less, and the discharge voltages of the entire device as a whole are significantly greater than in the device according to the invention.

Under the influence of overvoltage U on the collector, it is not permissible to break through the solid insulation between the intermediate electrodes 5 and the additional electrode 6, i.e. it is necessary that the discharge between the main electrodes develops, passing only through the intermediate electrodes and through the air spark gaps. Thus, the discharge voltage of the collector (spark gaps located on its surface) should be less than the breakdown voltage of solid insulation U _p <U _pr The breakdown voltage can be expressed in terms of the insulation thickness Δ (i.e., the thickness of the layer of insulating body) and the breakdown voltage of the material E _pr from which the insulating body is made: U _pr = Δ · E _pr Therefore, the thickness of the insulation must meet the condition

Thus, in order to ensure the necessary dielectric strength of the insulation, the thickness Δ _{i of the} insulating body 1 between the additional rod electrode 6 and the ith intermediate electrode 5 (i = 1, 2, ... m) should be selected from the condition

where U _{p, i} is the discharge voltage between the i-th intermediate electrode and the second main electrode;

E _CR - breakdown strength of the insulating material from which the insulating body 1 is made.

In order to reduce the cost of the device, as well as to further reduce discharge voltages, the insulation thickness between the intermediate electrodes 5 and the additional electrode 6 can be made different for different intermediate electrodes. The further the i-th intermediate electrode is from the second main electrode 3, the greater should be the discharge voltage U _{p, i} between them and, accordingly, the thicker the insulation layer Δ _i should be. In other words, the thickness of insulation between the additional electrode 6 and the ith intermediate electrode 5 should be directly related to the distance between the ith intermediate electrode and the second main electrode (in the general case, that main electrode that is electrically connected to the additional electrode).

The closer the additional electrode 6 to the intermediate electrode 5, the larger the capacitance C ₀ , and the lower the discharge voltage of the collector. Therefore, in order to reduce discharge voltages, it is advisable to arrange an additional electrode 6 along the entire insulating body 1 so that each intermediate electrode 5 is opposite the additional electrode 6. However, there may be cases where the guaranteed absence of insulation breakdowns is more important than reducing discharge voltages. In this case, the additional electrode may not be located along the entire length of the insulating body 1, but only overlap some part of it. In this embodiment, a part of the intermediate electrodes 5 located closer to the second main electrode 3 will be opposite the additional electrode 6, and the other part of the intermediate electrodes will be displaced along the longitudinal axis of the additional electrode. In this case, the distances between these intermediate electrodes 5 and the end of the additional electrode 6 (insulation thickness) will be significantly greater than when the additional electrode is located over the entire length of the insulating body 1. And in this case, the discharge voltage in the device according to the invention will be lower than in analogues, but not to such a significant extent, as in the case of the location of the additional electrode 6 along the entire insulating body 1. Obviously, the maximum increase in insulation thickness between the intermediate electrodes 5 and up olnitelnym electrode 6 while reducing the discharge voltage is reached at the location opposite the additional electrode only one intermediate electrode 5 closest to the second main electrode 3.

Figure 3 shows a variant of a collector with intermediate electrodes 5 arranged in a spiral. This arrangement makes it possible to place a greater number of intermediate electrodes 5 on the collector than in the embodiment of FIG. 1, and thereby further improve the arc-suppressing ability of the collector. Obviously, in this embodiment (as in other options discussed below), the insulating body and the additional electrode, at least in the installation area of the intermediate electrodes, preferably have a circular cross-section that facilitates the uniform distribution of the intermediate electrodes 5 on the outer surface of the insulating body 1 and equal thickness of the insulating layer in all radial directions.

Figure 4 shows a variant of a collector with intermediate electrodes in the form of pieces of insulated wire. The use of pieces of insulated wire as intermediate electrodes 5 makes it possible to place them closely on the surface of the insulating body 1 and thereby further increase the number of gaps into which the arc 7 is divided. Thus, the arc-suppressing ability of the collector can be further increased.

Figure 5 shows a variant of the collector device with intermediate electrodes 5 made in the form of rings covering the insulating body 1. Due to this arrangement of the intermediate electrodes, their capacitance to the additional electrode 6 is increased and, as shown above, the cascade effect of the operation of the collector device is enhanced , i.e. its discharge voltages necessary for the breakdown of interelectrode gaps are reduced. The performed experimental studies have shown that for the extinction of the arc, it is important that its individual sections (arches), which are formed due to the use of intermediate electrodes in the form of rings, are located as far as possible from each other. With this mutual arrangement of the arc sections, it is difficult to form a single arc channel when it is inflated during the flow of current and, therefore, the extinction of the arc is facilitated. It is important to fix the place of initiation of the arc. For this purpose, projections 8 on the annular intermediate electrodes serve. As can be seen from FIG. 5, each intermediate electrode 5 is preferably provided with two such protrusions located on opposite end faces of the ring, i.e. facing two adjacent electrodes. The length of each protrusion 8, of course, should be less than the distance from the end plane of the corresponding ring to the adjacent intermediate electrode 5 or (for extreme intermediate electrodes) to the adjacent main electrode 2, 3.

For the spatial separation of the arc sections along the lateral surface of the insulating body 1, the protrusions 8 on each intermediate electrode 5 are mutually offset along its circumference. Figure 5 shows that the offset of the protrusions 8 preferably corresponds to 180 °, but in any case it should not be less than 90 °. However, in order to facilitate the formation of discharge channels between adjacent intermediate electrodes 5, the protrusions 8 on adjacent electrodes facing each other are located opposite each other, i.e. without mutual displacement around the circumference of the ring.

An additional increase in the arc suppression ability can be achieved if the side surface of each ring-shaped intermediate electrode 5 is coated with an insulation layer and the rings themselves are made of a resistive material, for example, nichrome.

Figure 6 shows another variant of the collector, similar to the embodiment of figure 5. To provide a more reliable fixation of the place of development of the overlap between the protrusions 8 of the intermediate electrodes 5, and also so that after the formation of the discharge channels (arc segments 7) between the protrusions 8 to exclude the merging of individual arc segments into a single arc channel, the surface of the insulating body 1 and additional electrodes 5 are jointly coated with an insulation layer 18. On the surface of said layer 18, only projections 8 remain, between which a discharge develops. Thus, in comparison with the embodiment of FIG. 5, at a slightly increased cost (due to the application of an additional insulating layer 18), a higher arc-extinguishing ability of the collector device according to the invention is provided.

In Fig.7 shows a variant of the collector, resembling the variant of Fig.5. However, the insulating body 1 and the additional electrode 6 inside are made in this case in the form of a loop (i.e., have a U-shape). The length of the additional electrode 6 is preferably chosen equal to the length of the insulating body 1, and the first main electrode 2 is made in the form of a metal tube covering the insulating body 1 in its middle part. The second main electrode 3 in this embodiment can be mechanically connected to one or both ends of the insulating body 1 and electrically connected to the additional electrode 6. Depending on the specific conditions of use of the current-collecting body, for example, on the required number of intermediate electrodes, they can be located on one or on both shoulders of the insulating body. This design makes it possible to use a piece of cable as a blank for the collector device, in which the metal core acts as an additional electrode 6, and the cable insulation acts as an insulating body 1. Due to this, the manufacturability of the collector device is significantly increased, since the production of cable products is well technologically debugged, moreover, a very high quality of insulation can be ensured.

On Fig shows an embodiment of the collector device, which can be implemented on overhead lines with protected wires. A support insulator 12 is mounted on a support 13 of conductive material (reinforced concrete, steel, etc.), to which a wire 4 having an insulating protective layer is attached using a metal fastener (which in this embodiment also functions as the second main electrode 3). At the appropriate distance from the wire fastening, a biting clamp is installed, acting in this embodiment as the first main electrode 2. The insulating layer of wire 4 acts as an elongated insulating body 1, and wire 4 itself serves as an additional electrode 6. On the surface of the protected wire 4, intermediate electrodes 5 are installed .

According to one of the possible options, the intermediate electrodes 5 can be pre-mounted on a tape of insulating material, which is then fixed on the wire (for example, by winding onto it) between the first main electrode 2 and the second main electrode 3. In this case, the set of intermediate electrodes 5 is located in a spiral, similar to that shown in Fig.3. When the overvoltage acts on the wire 4, the insulator 12 is first blocked, and the fastening means (the second main electrode 3) is under the ground potential, i.e. under zero potential. The wire 4 and, accordingly, the biting clamp are under a surge potential. Thus, between the second main electrode 3 and the biting clamp (the first main electrode 2), an overvoltage occurs, under the action of which all the gaps between the main electrodes 2, 3 and the intermediate electrodes 5 sequentially overlap.

Fig. 9 shows an embodiment of a down conductor device based on an insulating strapping 17, by means of which a protected overhead power transmission wire is attached to an insulator 12 mounted on a support 13. At least one of the shoulders of the strapping 17 has intermediate electrodes 5 made in the form of metal rings, and the ring closest to the insulator 12, performs the functions of the second main electrode 3. The end of the strapping 17 is attached to a biting clip, i.e. to the first main electrode 2. As in the previous version, the insulating layer of the wire performs the function of an elongated insulating body 1, and the wire itself (passing inside the insulating layer) serves as an additional electrode. Similarly to the previous embodiment, when exposed to overvoltage, the overlap channel 7 first develops along the insulator 12 between the support and the second main electrode 3, and then there is a cascade overlap of the air gaps between the intermediate electrodes 5 installed on the strapping 17.

Figure 10 shows partial views of a 10 kV overhead line, for which lightning protection is used another version of the collector according to the invention. The down conductor device in this embodiment is made in the form of a piece of cable having insulation forming an insulating body 1, and a metal core inside the insulation, acting as an additional electrode 6. In the middle part of the piece of cable, a metal tube is installed on top of the insulating body 1, which serves as the second main electrode 3 and the cable terminators perform the functions of the first main electrodes 2. The ends of the cable core (that is, the additional electrode 6) are attached to the 4 VL wire using clamps 11. The second main electrode 3 by means of a bracket 15 and a wire 16 is attached to an insulator 12 mounted on a support 13 of the overhead line. An electrode 14 is also mounted on the support 13, forming a spark discharge gap S with a second main electrode 3 (for a 10 kV OHL, S = 2 cm). On the length of the cable there are metal rings forming intermediate electrodes 5.

When the overvoltage acts on the wire 4 of the overhead line, the cable core (i.e., additional electrode 6) connected to wire 4 receives high potential through the terminators. Due to the strong capacitive coupling between the additional electrode 6 and the metal tube, this tube also acquires high potential. The VL support 13 and the electrode 14 connected to it have zero potential, because the support 13 is grounded. A potential difference (high voltage) occurs between the second main electrode 3 (metal tube) and the electrode 14, under the influence of which the spark air gap S breaks through, so that the second main electrode 3 acquires zero potential (earth potential). After that, all the overvoltage appears to be applied between the cable core and the second main electrode 3. Under the action of this overvoltage on the cable surface in one or both directions, depending on the magnitude of the overvoltage, slip discharge channels develop, sequentially overlapping the gaps between the rings, i.e. between the intermediate electrodes 5. After the overvoltage passes through the discharge channels, an accompanying current of industrial frequency flows, which heats up the overlap channel and transfers the spark discharge into an arc. Due to the breaking of the arc with the help of intermediate ring electrodes 5 into separate sections (arches), cooling of the arches on cold metal rings takes place. Due to this, the collector with rings extinguishes a much larger current than the collector without rings. In other words, the collector device according to the invention with a fairly simple design (and therefore low cost) has an increased arc suppression ability.

This conclusion is confirmed by experimental verification. For this purpose, down conductors were manufactured and tested for a voltage class of 10 kV, both with intermediate ring electrodes and without rings. The main parameters of the tested down conductors are as follows:

- a cable of the PIGR-8 type manufactured by the Sevcable plant with an aluminum core of 9 mm diameter and 4 mm thick polyethylene insulation;

- the length of one shoulder (from the edge of the metal tube to the edge of the clamp) 800 mm;

- the distance between the rings is 50 mm.

Tests have shown that both tested down conductors (with rings and without rings) protect the overhead line insulator from thunderstorms, however, the down current device without rings ensures the extinction of the accompanying current arc at currents up to 150 A, and the collector with rings - at currents up to 600 A. This means that a collector without rings can be put into operation on a 10 kV overhead line only if the accompanying current does not exceed 150 A, for example, if the support grounding resistance is greater than or equal to 40 Ohms. In operation, however, there is a fairly large number of supports having a resistance of 10 to 30 ohms. Such supports are used, for example, when passing overhead lines in a populated area. As for the collector with rings, it can be placed on a support with a low ground resistance, up to 10 Ohms, i.e. almost any support. Thus, the scope and reliability of the collector of the present invention is significantly increased.

Experimental studies and calculations also showed that the diameters of the insulating body and the additional electrode are preferably selected in the ranges of 8-60 mm and 3-50 mm, respectively. The distance between the main electrodes, for example, for a 10 kV overhead line, it is advisable to choose between 600-1000 mm. An acceptable discharge distance between adjacent intermediate electrodes is in the range of 1-100 mm, and a preferred interval for this distance is 1-80 mm. Thus, the total number of intermediate electrodes can actually be from 8 to 1000. Naturally, in relation to other voltage classes and other specific tasks of lightning protection (for example, in relation to protection against inducted voltages or from direct lightning strikes), such (probably, other ) device parameters that are optimal specifically for the particular problem being solved. Moreover, the more intermediate electrodes are used, the better arc extinction is. However, with an increase in the number of intermediate electrodes with a constant total length of the discharge gaps, the dimensions and cost of the collector device increase. The optimal design of the collector, as applied to a specific task, should therefore be decided on the basis of the given initial parameters: the type of structures or equipment to be protected, voltage class, equipment protection level, etc.

The variants and modifications of the execution of the collector device according to the invention and the power line constructed using such devices described in this description are presented 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 (25)

1. A down conductor device for lightning protection of electrical components, power lines, structures or structures, comprising an insulating body made of a solid dielectric, at least two main electrodes mechanically connected to the insulating body, and m intermediate electrodes located on the insulating body between the main electrodes with mutual displacement, at least along the longitudinal axis of the insulating body, characterized in that an additional body is installed along the axis of the insulating body along its axis terzhnevoy electrode electrically connected to one of main electrodes and is located opposite the at least one of the intermediate electrodes, wherein the layer thickness of the insulating body between the additional electrode electrically connected with the main electrode, and the i-th intermediate electrode is selected satisfying

where Δ _i is the insulation thickness between the additional electrode electrically connected to the main electrode and the ith intermediate electrode (i = 1, 2 ... m); U _{p, i} is the discharge voltage between the i-th intermediate electrode and the main electrode, electrically connected to the additional electrode; E _CR - breakdown strength of the insulating material from which the insulating body is made. 2. The collector according to claim 1, characterized in that the line along which the intermediate electrodes are located with mutual displacement is oriented parallel to the longitudinal axis of the insulating body. 3. The collector according to claim 1, characterized in that the insulating body and the additional electrode, at least in the area of installation of the intermediate electrodes, have a circular cross section. 4. The collector according to claim 3, characterized in that at least one intermediate electrode is made in the form of a ring. 5. The collector according to claim 4, characterized in that the single or each intermediate electrode, made in the form of a ring, is equipped with a pair of protrusions located on the opposite end faces of the ring and mutually offset by its circumference by at least 90 °, the length of each protrusion is chosen less than the distance from the end plane of the ring to the adjacent intermediate electrode. 6. The collector according to claim 5, characterized in that the mutual displacement of the protrusions around the circumference of the ring is chosen equal to 180 °. 7. The collector according to claim 5, characterized in that the side surface of each ring is coated with a layer of insulation. 8. The collector according to claim 4, characterized in that at least two adjacent intermediate electrodes are made in the form of rings and provided with a pair of protrusions, and the protrusions facing each other on adjacent electrodes are located without mutual displacement around the circumference of the ring. 9. The collector according to claim 8, characterized in that the surface of the insulating body and the side surface of the rings, with the exception of protrusions made on them, are coated with an insulation layer. 10. The collector according to claim 1, characterized in that the insulation thickness between the additional electrode and the corresponding intermediate electrode is directly related to the distance between this electrode and the main electrode electrically connected to the additional electrode. 11. The collector according to claim 2, characterized in that the insulating body is U-shaped, the length of the additional electrode is chosen equal to the length of the insulating body, the first main electrode is made in the form of a metal tube covering the insulating body in its curved part, and the second main the electrode is mechanically connected to one or both ends of the insulating body and electrically connected to an additional electrode, while the intermediate electrodes are located on one or both shoulders of the insulating body. 12. The collector according to claim 11, characterized in that the additional electrode is a core of a segment of an electric cable, and the insulating body is an insulation of said segment of an electric cable. 13. The collector according to claim 1, characterized in that the intermediate electrodes are made in the form of metal plates with rounded edges. 14. The collector according to claim 1, characterized in that the intermediate electrodes are made in the form of segments of an insulated wire. 15. The collector according to claim 1, characterized in that the line along which the intermediate electrodes are located with mutual displacement has a spiral shape covering the surface of the insulating body. 16. The collector according to claim 1, characterized in that the intermediate electrodes are mounted on a tape of insulating material fixed to the surface of the insulating body. 17. The collector according to claim 16, characterized in that said tape of insulating material is spirally wound onto the surface of the insulating body. 18. A collector according to any one of claims 1 to 9, characterized in that the elements to be protected are overhead power line elements of a voltage class of 10 kV, while the diameters of the insulating body and the additional electrode are selected to be 8 ÷ 60 mm and 3 ÷ 50 mm, respectively and the distances between the main and intermediate electrodes are 600–1000 mm and 1–100 mm, respectively. 19. The collector according to claim 1 or 2, characterized in that the protected elements are the elements of the electrical equipment of the radar and the radome of the radar antenna, the second main electrode is electrically connected to the body of the radar and to the additional electrode, while the main and additional electrodes are made in the form of parallelepipeds, and the insulating body is in the form of a hollow parallelepiped, the cavity of which is filled with an additional electrode. 20. A collector according to any one of claims 1 to 9, characterized in that the elements to be protected are power line elements, wherein at least one first main electrode is connected directly or through a spark discharge gap to the element to be protected, and the second main electrode directly or through a spark discharge gap connected to the ground. 21. A power line comprising supports with insulators, at least one electrically conductive wire connected to the insulators by means of fastening devices, and at least one current-conducting device for lightning protection of power line elements, characterized in that the current-conducting device for Lightning protection is made in the form of a down conductor device according to claim 20. 22. The line according to item 21, wherein the energized wire is located inside the insulating protective layer, the first main electrode is made in the form of a biting clip installed on the insulating protective layer and electrically connected to the wire, and the intermediate electrodes are installed on the surface of the insulating protective layer. 23. The line according to item 21, characterized in that at least one mounting device is made in the form of an insulating strapping, and the intermediate electrodes are made in the form of metal rings mounted on an insulating strapping with an offset along the length of the strapping relative to adjacent main electrodes, the second main electrode is located near the insulator. 24. The line according to item 21, characterized in that the down conductor device for lightning protection contains a length of cable, the insulation of which forms an insulating body, and a metal core - an additional electrode, the first two main electrodes made in the form of terminators of the length of the cable, clamps, through which the ends the cable section is attached to the wire of the high voltage line, and the second main electrode, made in the form of a metal tube mounted in the middle of the cable section and attached to the support insulator, while Meth electrodes are in the form of rings mounted on the insulating body between the second main electrode and the first main electrodes mutually displaced along the length of the insulating body and mounted on a support for forming the auxiliary electrode with the second main electrode of the spark discharge gap. 25. A power line containing supports with insulators, at least one electrically conductive wire connected to the insulators by means of fastening devices, and at least one current-conducting device for lightning protection of power line elements, at least one the main electrode of the collector directly or through the spark gap is connected to the protected element, and at least one other main electrode directly or through the spark discharge ny gap is connected to earth, characterized in that the collector device for the lightning protection is designed as a collector device according to any one pp.10-18.

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