Overhead conductor with thin insulation layer

Abstract

The invention discloses an overhead conductor with a thin insulation layer. The overhead conductor comprises an overhead conductor core (1) and a thin insulation layer (2) coating the periphery of theoverhead conductor core (1). The center of the overhead conductor core (1) is formed by twisting of one or more galvanized steel wires, aluminum-clad steel wires, or aluminum alloy wires. And then one or multiple layers of aluminum wires or aluminum alloy wires are twisted outside the overhead conductor core based on a conventional method. The center of the conductor plays a role in bearing the tensile force; and the outer aluminum wire or aluminum alloy wire play a role in electric conduction and partial tensile resistance. According to the invention, the conductor is easy to construct and corona occurrence as well as icing or snow accumulation is avoided. With the thin insulation layer, the diameter and self-weight of the ordinary overhead insulated cable are reduced; the tower has thelow load, the sag is small, the wind load coefficient is small, the vibration is low, and the safety factor is high. Moreover, entrance of rainwater or salt mist in the conductor is avoided; the strand is protected from chemical corrosion; and thus the service life of the conductor is prolonged.

Description

technical field [0001] The invention relates to a power transmission line, especially a high-voltage and ultra-high-voltage overhead wire, in particular an overhead wire with thin insulation. Background technique [0002] At present, there are two types of known overhead wires: the first type is the bare metal overhead stranded wire, which is generally made of concentric twisted round wires, and the center part is galvanized steel wire, aluminum-clad steel wire or high-strength aluminum alloy wire The outside is aluminum wire or high-strength aluminum alloy wire layered and twisted in sequence; the other is to extrude the insulation layer on the basis of the first type. According to the different voltage levels, it is divided into low-voltage overhead insulated cables and medium-voltage overhead insulated cables. cable. Low-voltage overhead insulated cables have only insulation, medium-voltage overhead insulated cables have conductor shield and insulation layer, or conducto...

AI Technical Summary

Problems solved by technology

During the use of the first type of overhead conductors, one is directly twisted with the same or different metal wires. During the laying and setting out process, the wire strands are easy to loose due to the residual stress, which causes construction difficulties or leaves behind. The second is that the surface of the wire is composed of round single wires, which are uneven and easy to form corona. Especially when used on high-voltage and ultra-high-voltage overhead lines, corona is more likely to occur. In order to reduce corona discharge, it is often used The third is that due to the uneven surface of the conductor, it is easy to accumulate snow, and because the metal single wire is directly exposed to the air, the temperature drops quickly, and it is easy to accumulate ice under unfavorable weather conditions. The line is damaged; the fourth is that the contact surface between the round single wires is small, and the rainwater almost surrounds the entire single wire. The strands will be broken due to chemical corrosion, which will cause difficulties in power transmission or the danger of disconnection. When used on islands, rain or salt spray will be more corrosive

Although the second type of overhead insulated cable adds an insulating layer (or insulating layer and shielding layer) outside the bare conductor, it can overcome some of the shortcomings of the bare conductor, but it causes the tower load to increase, the arc sag to decrease, and the wind load coefficient to be large. The vibration is aggravated and the safety factor is small, so it can only be used on medium and low voltage overhead lines

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