BG4398U1 - System for the protection of high-voltage conductors of overhead power lines from corona effect - Google Patents

Abstract

This utility model relates to the area of electrical engineering and accordingly to a system for the protection of utility elements, more specifically for the protection against the harmful impacts which the corona effect has on high-voltage overhead power lines rated from 220 V to 400 V. The described system consists of a protective body which has openings attached to a non-conductor and is provided with a connective terminal, wherein the protective body (1) is made of silicon, has the shape of a trapeze and includes two symmetrical lids with three chutes such that the lids are connected to one another by insulator pins (4) and form in the ends of the protective body (1) three openings (1а, 1б and 1в), wherein inside the body (1) is accommodated the connective terminal (6) which, through one opening (1a) of the body (1) is connected to the lower end of the insulator circuit (7) and, through the other two openings (1б and 1в), the connective terminal (6) is connected respectively to the two ends of the conductor (5) which is coated in tubular silicon insulation (2) (coating), wherein the two ends of the conductor (5) are hermetically sealed to the connective terminal (6) by means of self-curing silicone tape (3) and the protective body (1) overlaps the conductor (5) on each side of the connective terminal (6) by a section 2–3 centimeters long, while the tubular silicon insulation (2) of the conductor (5) covers the two sides of the conductor (5), and wherein the lower end of the insulator circuit (7) is equipped with an anti-arc screen (8). The system is also suitable for a glass insulator or for a silicone insulator, in particular for a suspended glass insulator with a load-bearing connective terminal (6) as well as for a tensioning insulator with a tensioning connective terminal (6). The system according to this utility model ensures full protection against the corona effect, improves the electrical and mechanical performance of the power grid, prevents the infliction of losses on power supply organisations caused by the corona effect, reduces the losses of energy, and achieves a significant economic effect by extending the service life and the reliability of high-voltage overhead transmission lines.

Description

Field of technique

The utility model relates to the field of electrical engineering, respectively to a system for the protection of equipment elements, in particular for protection against the harmful influence of the "corona" effect on overhead power lines of high voltage from 220 to 400 kV.

Prior art

It is known that the air between the transmission lines during the transmission of electrical energy acts as a dielectric medium (ie it is an insulator between the conductors of the power lines). However, when a voltage is induced between the conductors of an alternating character, a charging current also flows between them. The resulting line voltage of the conductor is the main determining factor for corona discharge in transmission lines. As the voltage increases, the "corona" effect in the transmission line caused by the ionization of the atmospheric air around the conductors is mainly influenced by the condition of the cable, the distance between the conductors, as well as the physical condition of the atmosphere. The "corona" effect is observed in all types of transmission lines, but becomes noticeable at higher voltages (220 kV and higher). The gradient of the resulting electric field is greatest at the surface of the wire and at a smaller diameter. The resulting corona discharge leads to a loss of power. Energy is lost in the form of light, sound, heat and chemical reactions. Although these losses are individually small, over time they lead to significant power losses in high-voltage networks. Hanging and tension insulators are mainly used to suspend power line conductors to supporting structures and are an important item of overhead power line equipment to isolate and protect energized conductors from grounded poles. In this way, live wires that are part of the electrical installation approach the insulator perpendicular to the axis of the insulator of the suspension or one wire approaches perpendicularly and the other linearly to the axis, being fixed at the lower end of the insulator circuit. In order to ensure the safety and efficiency of operation of the power transmission network, insulators are usually equipped with various items of equipment such as bird protection elements, arc screens, etc.

Known from RU 2766554 are screen fittings (arc protection screens) for high-voltage insulation structures, containing at least two rings of different diameters, connected to each other by a spacer, and a fastening element, where the ring with a smaller diameter is made with an arcuate section in the form of a toroidal segment whose arc radius centers are located in the inner region of the screen reinforcement, while the smaller diameter ring has a cross-section in the form of a plane bounded by a circle, oval, polygon. The disadvantage of this technical solution is the insufficient efficiency of screen fittings in equalizing the electric field of a high voltage insulator.

Also, from RU 2749074 a device for protecting birds from electric shock is known, provided with an elongated housing made of dielectric designed to accommodate a part of the wire attached to the insulator and/or at least part of the member for attaching the wire to the insulator, in addition, it has an opening or cut-out in the side wall of its middle part of the housing, designed to accommodate an insulator terminal and/or at least part of the wire-to-insulator fastener. The body has a length of 1000 to 3000 mm. The described device is in the form of a monolithic body or a body assembled from several elements, but without the possibility of separating them from each other, connected by welding or by bonding. In the case of the monolithic housing, at least one cut is provided in its middle part, through which, for example, an end fitting can be passed. The device can also be demountable, consisting of two, three or more parts. The cover can be additionally equipped with spikes in its upper part, or with other protrusions that make it unattractive for birds to land on. The device can be provided with the possibility of fixing by means of plastic clamps, connectors fixed on both sides of the middle part and covering the housing together with the conductor. The lower part of the housing is formed with openings allowing the passage of fixing elements such as clamps, ties, wire, bolts and/or screws.

This device provides only the protection of birds landing on a wire fixed with only one type of insulator (hanging) from electric shock, and does not provide reliable protection of an electrical installation at high voltages. The housing is intended only for operation with voltage up to 36 kV.

The purpose of the present utility model is to provide such a device that gives full protection against the occurrence of the "corona" effect and at the same time reduces the mechanical load on the poles of overhead power lines for high voltage (220 - 400 kV) with a guaranteed reduction in energy losses in conditions of high operating voltage.

Technical nature of the utility model

This problem is solved by means of a system for protecting against "corona" effect on high-voltage power lines of an overhead power transmission network, consisting of an insulating body, which is a trapezoidal protective housing with three openings, including two symmetrical covers equipped with three channels for the openings, which are connected to each other by means of insulating pins by means of dielectric glue. The housing is made of silicone rubber (SiR) with a dielectric strength of 14 kV/mm. The inside of the housing houses a connecting terminal, which through one hole of the housing is connected to the lower end of an insulator circuit, and through the other two holes of the housing, the terminal is connected to both ends of the conductor, on which silicone pipe insulators (covers) are located. , which are hermetically sealed at both ends to the connection terminal by means of self-curing silicone tape. The housing overlaps a 2 cm - 3 cm section of the silicone tube insulator insulated wire on both sides of the connection terminal. The system is suitable for glass and silicone insulators of hanging or tension type, respectively equipped with bearing or tension terminals. Silicone pipe covers cover the conductor with a 2.5 m - 3.5 m section on both sides or its entire length between two tension terminals on a pole. The lower end of the insulator circuit from the insulator is equipped with an arc shield. The length of the silicone coating for the wires generally varies from 5 m to 7 m for one phase and from 15 m to 20 m for one pole.

The system, according to the present utility model, by means of the used silicone casing and silicone coating of the conductors, provides reliable protection from the "corona" effect, is applicable to power lines for voltage 220-400 kV using standard insulators and terminals, and generally improves the electrical and mechanical parameters of the electrical network. The use of the silicone material for the proposed construction greatly eases the installation, as it is easily connected to the insulators pre-fitted to the conductors of the power line. With the use of this system, the need for bundled wires is eliminated, which in turn reduces the mechanical load on the poles by 2-3 times, without reducing the carrying capacity of the power line. When building new power lines, the described device guarantees a reduction in costs for 2-3 wires in a bundle, where the economic effect reaches up to 70%. The system thus constructed generally prevents damage to power supply organizations arising from the "corona" effect, reduces energy losses, achieves a significant economic effect by achieving increased service life and reliability of overhead power lines for high voltage from 220 to 400 kV.

Explanation of the attached figures

Figure 1 represents an exemplary embodiment of the protection system with a hanging insulator and a vertical section of the housing, according to the utility model;

Figure 1-1 is a view of a silicone housing cap with connecting pins for a pendant insulator;

figure 2 represents an exemplary embodiment of the protection system with a tensile insulator and a vertical section of the housing;

figure 2-1 shows a vertical section of a case with a silicone strain insulator cap;

Figure 2-2 shows an insulating case for a strain insulator.

Examples of implementation of the utility model

The system for protecting against corona "effect" of power lines according to the presented figs. 1 and fig. 2 of the present utility model consists of an insulating body, which is a trapezoidal protective housing 1, including two symmetrical covers (halves) provided with three channels 1a, 1b and 1c, which are designed to hold the wire covered with silicone tubular insulation 2 5 and the lower end of the insulating circuit 7, where the two covers of the housing 1 are connected to each other by means of insulating pins 4 by means of dielectric glue, defining three holes 1a, 1b and 1c inside the protective housing 1. Inside the protective housing 1 is housed a supporting (fig. 1) or tension connection terminal 6 (fig. 2), which is connected to the lower end of the insulating circuit 7 through one opening 1a of the housing 1, and through the other two housing openings 1b and 1c, the terminal 6 is connected to both ends of the conductor 5, on which is placed a silicone pipe insulation 2 (cover) for the conductor 5, hermetically sealed at both ends to the terminal 6 by means of a self-vulcanizing silicone tape 3.

The conductor 5 has two covered sections with 2.5 m - 3.5 m of silicone pipe insulator 2, located on both sides of the connecting terminal 6. The connection of the insulator by means of the lower end of the insulator circuit 7 to the phase conductor 5 of the power line is carried out with using standard connecting terminals 6. The lower end of the insulator circuit 7 is also equipped with an arc protection screen 8.

The protective housing 1 is designed to be attached to a tension or carrier terminal for a wire and is made of silicon rubber SiR with a dielectric strength of 14 kV/mm, and the connection of the two covers of the housing 1 is by means of composite pins and insulating glue.

The connection terminal 6 is a standard carrier terminal (Fig. 1) or a standard tension terminal (Fig. 2), respectively, for hanging and tension insulators made of glass or silicone.

Installation is done in several steps:

1. There is no pre-assembly on the ground;

2. At the place of installation:

• place the two silicone tube covers 2 on the conductor 5 tightly next to the supporting connection terminal 6 (fig. 1) or the tensioning (fig. 2) connection terminal, then place the housing 1 so that it overlaps a 2 cm section of the two sides of silicone pipe insulation 2;

• Before closing the pipe cover 2 and the two housing covers 1, the wire 5, the connection terminal 6, the lower part of the insulator circuit 7, the inner part of the silicone pipe cover 2 and the silicone covers of the housing 1 are sprayed with semiconducting spray to avoid the occurrence of partial discharges;

• The silicone tube cover 2 on the side of the bare conductor 5 (only for carrying insulator circuits (fig. 1)) and to the connecting terminal 6 are covered with a self-vulcanizing silicone tape 3 for hermetically closing the system;

• The silicone pipe cover 2 is closed by means of a zipper previously coated with a dielectric glue with a dielectric strength of 14 kV/mm and pressed;

• The silicone housing 1 and the terminal itself 6 are covered with semiconducting spray;

• The outer edges of one cover from the housing 1 and connecting pins 4, are covered with dielectric glue with a dielectric strength of 14 kV/mm, pressed to the second treated with dielectric glue in the same way cover from the housing 1 and to the conductor 5, which hermetically and electrically closes the two covers and insulates the housing 1 so that the housing 1 overlaps a 2 cm section on both sides of the silicone pipe insulation 2;

• The part of the cover from the housing 1 to the lower end of the insulator circuit 7 is covered in its contact surface with the other half of the cover 1 of the housing with a self-vulcanizing silicone tape 3 to hermetically close the system.

The length of the silicone pipe insulation 2 depends on the voltage of the power line. In case of hanging, insulating circuits (Fig. 1), it is 2.5 m for 220 kV and 3.5 m for 400 kV. In tension circuits (Fig. 2), the silicone pipe insulation 2 for conductor 5 covers the entire length between two tension connection terminals 6 on one pole. The two ends of the silicone pipe insulation 2 are hermetically sealed using a self-vulcanizing silicone tape 3.

The silicone housing 1 is common to the connecting terminal 6 and the wire 5 in both types of insulators, overlapping a 2 cm section of the wire on both sides of the gripping connecting terminal 6.

The system is suitable to be used to protect against the "corona" effect for circuits made of glass and silicon (composite) insulators.

The length of the silicone coating for the wires is generally from 5 m to 7 m for one phase and from 15 m to 20 m for one pole.

The system provides complete, reliable protection against the "corona" effect. It is applicable to power lines for voltage 220 - 400 kV using standard insulators and terminals, which leads to improvement of its electrical and mechanical parameters. The silicone coating used on the wires eliminates the need for bundled wires, thereby reducing the mechanical load on the poles by 2-3 times, without affecting the carrying capacity of the power line.

The silicone material used significantly eases the installation, the silicone housing is easily connected to the pre-installed insulators on the wires of the power line. Assembly takes place in a short time and one operator is sufficient.

Claims (1)

A system for protecting against corona effect on high-voltage power lines of an overhead power network, consisting of a protective housing with openings attached to an insulating circuit, provided with a connecting terminal securing a conductor to the insulator, characterized in that the protective housing (1) is trapezoid-shaped silicone and includes two symmetrical covers equipped with three channels, which covers are connected to each other by means of insulating pins (4) so as to form at the ends of the protective housing (1) three holes (1a, 1b and 1c), and a connecting terminal (6) is located inside the housing (1), which is connected to the lower end of an insulating circuit (7) through one hole (1a) of the housing (1), and through the other two holes ( 1b and 1c) the connecting terminal (6) is connected respectively to the two ends of a wire (5) which is covered with silicone pipe insulation (2), where both ends of the wire (5) are hermetically sealed to the connecting terminal (6) by means of self vulcanizing a silicone strip (3) is spread, with the protective housing (1) overlapping the wire (5) on both sides of the connecting terminal (6) with a section of 2 cm - 3 cm each, and the silicone pipe insulation (2) of the wire (5 ) is covering the conductor (5) on its two sides, and the lower end of the insulator circuit (7) is equipped with an arc protection screen (8).