RU2316866C1 - Deicing device for overhead line - Google Patents

Abstract

FIELD: electrical engineering; deicing devices for overhead power transmission line conductors.

SUBSTANCE: proposed deicing device for overhead line conductors has conductor section assembled of two relatively insulated groups of wires. On one end these wire groups are interconnected and connected to next section of overhead line and on other end first wire group is connected to preceding section of overhead line and independent voltage supply is inserted between first and second wire groups.

EFFECT: enhanced reliability of deicing line conductors without load disconnection.

1 cl, 2 dwg

Description

Technical field

The invention relates to the field of electrical engineering, in particular to devices that prevent the formation of ice on the wires of overhead lines (VL) power transmission.

State of the art

It is known that ice deposition on overhead lines leads to wire breaks, short circuits, and even falls in overhead lines, which greatly complicates the supply of electricity to consumers and leads to emergency situations in providing residential areas.

One of the most common ways of eliminating ice from overhead lines is to melt ice. The disadvantages of this method are that, on the one hand, it is switched on upon the formation of ice on the wires and, on the other hand, such melting requires shutting down consumers for several hours.

In some cases, the formation of ice can be prevented by increasing the operating current on the overhead lines. However, this requires a change in the scheme of the substation to which the overhead line is connected, which in many cases is not feasible. Therefore, the previous method is more common.

A device is known in which the prevention of ice is supposed to be carried out using new wires, the design of which differs from the known standard wires [1]. According to [1], the wire is located inside the conductive sheath with a gap of 2.5 mm. This gap is filled with insulation with a given active component of the insulation resistance. The applied voltage between the sheath and the wire increases the temperature of the wire caused by the active component of the current through the gap insulation. According to [1, 2], ice formation can be prevented in this way if the heating power of the wire is only 50 W with a wire length of 100 km. As our calculations showed, for example, for AC 95/16 wire with a diameter of 12 mm and an insulation thickness between the wire and the sheath equal to 2.5 mm, the indicated power of 50 W with a wire length of 100 km will take place with an insulation tgδ of 10%, and voltage between the sheath and the wire 1 kV. The author [1] did not indicate the required value of the heating power of the wire under conditions of ice formation, for example, at a given wind speed on the overhead line.

It is known, for example, according to [3] and [4] that, with a relatively low wind speed of 3 m / s and a required temperature increase of 5 ° C above the ambient temperature, the required heating power of the specified wire 100 km long should be several hundred kilowatts, which is not comparable with the power indicated by the author [1].

On the other hand, local delamination of the insulation from the wire and the sheath can occur both during installation of the wire and during its long-term operation due to vibration and dancing of the wires, which makes it difficult to prevent icing.

SUMMARY OF THE INVENTION

The aim of the invention is to reliably prevent the formation of ice on the overhead line without disconnecting consumers.

This goal is achieved by the fact that in the considered OHL section, a wire is used in which one part of the OHL wire wires is isolated from the remaining wires of this OHL wire section.

The essence of the invention lies in the fact that the device included in the OHL section, where ice formation is possible, consists of two groups of wires isolated between each other, which are connected at one end to each other and to the wire of the next OHL section, and one (first) at the other a group of wires is connected to the wire of the previous OHL section, and an independent voltage source is connected between the first and second groups of wires. In the absence of ice formation threat, the second group of wires is connected to the first group of wires.

The implementation of the invention

The essence of the invention is illustrated using the drawing on the example of the wire ACS 95/16.

The device for preventing the formation of ice on the overhead line consists of the first 1 and second 2 groups of wires isolated between each other, which are connected at one end to each other and to the wire of the next OHL section 3, and from the other, the first group of wires is connected to the wire of the previous OHL section 4 and between the first 1 and second 2 groups of wires connected to an independent voltage source 5.

The main current of the line passes from the wire of the previous section of OHL 4 to the first group of wires 1 and then to the wire of the next section of OHL 3. From an independent source 5, a voltage is applied between the first group of wires 1 and the second group of wires 2.

As mentioned above, to prevent the formation of ice on the ACS 95/16 wire, the excess of the temperature of the wire relative to the environment should be equal to 5 ° C at a wind speed of 3 m / s. In this case, 36 kW / 10 km should be allocated on the wire. At the rated current of this wire, active losses over a length of 10 km are 28 kW / 10 km. Therefore, the power from an independent voltage source 5 should be 8 kW / 10 km. If there is no line load, then the power of independent source 5 should be 36 kW / 10 km.

If the second group of wires is an insulated steel wire with a diameter of 4.5 mm, then with a loss power of this wire of 36 kW / 10 km, the voltage of an independent source 5 will be 2.1 kV and a current of 17 A. With an isolated second group of wires made of aluminum, with a power loss of 36 kW / 10 km, the voltage of an independent source will be 0.8 kV and a current of 45 A.

An independent voltage source can be a voltage transformer, powered by a 0.38 kV network with insulation of 63 kV relative to the ground for 110 kV substation, or a transformer far from the main station, fed directly from 110 kV overhead lines.

Information sources

1. US patent No. 1182005/0167427 A1.

2. Energy abroad. 2005, T.3, p. 18-19.

3. S. S. Kutateladze. Fundamentals of the theory of heat transfer. - Novosibirsk .: Science, Siberian Branch, 1970, p.660.

4. F.N. Mamin. On the thermal regime of ice melting on wires and cables of mountain power lines. // Wind and icy effects on the construction of mountain overhead lines: Collection of scientific papers. / ENIN them. G.M. Krzhizhanovsky. M .: 1988, p. 150-155.

Claims (1)

A device for preventing the formation of ice on an overhead line, comprising a section of an overhead line wire consisting of two groups of wires isolated between each other, which are connected at one end to each other and to a wire of a subsequent section of an overhead line, and at the other end, a first group of wires is connected to a previous wire section of the overhead line, and between the first and second groups of wires included an independent voltage source.