Application of glass insulators in power transmission lines

Mar. 29, 2022

The transmission line is a power facility that uses insulators and corresponding fixtures to overhang wires and overhead ground wires on towers to connect power plants and substations for the purpose of transmitting electricity. Mainly by the wire, overhead ground line, insulators, fixtures, towers, foundations, grounding devices and other components.

1. Conductor: Its function is mainly to transport electrical energy. Line wire should have good electrical conductivity, sufficient mechanical strength, vibration fatigue and resistance to chemical impurities in the air corrosion ability. Line conductors are often used in steel-core aluminum stranded wire or steel-core aluminum alloy-stranded wire. In order to improve the transmission capacity of the line, reduce corona, reduce interference with radio communications, often using two or four wires per phase consisting of split wire type.

2. Overhead ground line: the main role is to protect against lightning. Due to the shielding of the wire overhead ground, and wire, overhead ground coupling between the cooperation, which can reduce the chance of lightning directly hitting the wire. When lightning strikes the tower, the lightning current can be shunted through the overhead ground part, thus reducing the top potential of the tower, improving the level of lightning resistance. The overhead ground line is often used galvanized steel-stranded wire. At present, often using steel-core aluminum strands, aluminum-clad steel strands, and another good conductor, can reduce the asymmetric short circuit frequency overvoltage, reduce the potential supply current. Also has a communication function using optical composite overhead ground wire.

3. Insulator: is the wire insulated fixed and suspended in the tower objects. Insulators commonly used in transmission lines are disc-shaped porcelain insulators, disc-shaped glass insulators, rod-shaped suspended composite insulators.

(1) Disc-shaped porcelain insulators: domestic porcelain insulators, there is a high rate of deterioration, the need to test the zero value, maintenance workload. When encountering lightning strikes and fouling flash, it is prone to drop string accidents and has been gradually eliminated.

(2) disc-shaped glass insulators: with zero value self-detonation, but the self-detonation rate is very low (generally a few ten thousandths). Maintenance does not require detection, tempered glass parts in case of self-detonation after their residual mechanical strength still reaches more than 80% of the damage pull, still ensuring the safe operation of the line. Encounter lightning strikes and dirty flash will not happen to drop the string accident. In the Ⅰ, Ⅱ taint area has been commonly used.

(3) rod-shaped suspension composite insulator: with good anti-fouling flash performance, lightweight, high mechanical strength, less maintenance and other advantages, has been commonly used in the Ⅲ and above tainted areas.

4. Hardware

Power transmission line fixture, according to its main performance and use can be divided into wire clip class, connection fixture class, connection fixture class, protection fixture class, pulling wire fixture class.

(1) line clip class.

A. Suspended wire clip: used to fix the wire in a straight line tower on the hanging insulator string, or overhead ground wire suspended in a straight line tower on the overhead ground wire bracket.

B. Tensioning line clip: is used to fix the wire or overhead ground wire on the tensioning insulator string, playing an anchoring role. Tensioning clips have three categories, namely: bolt-type tensioning clips; compression-type tensioning clips; wedge-type clips.

C. Bolt-type tension-resistant clamps: is to borrow the vertical pressure of the U-shaped screws and clamps the friction effect of the wavy wire groove to fix the wire.

D. Compression type tensile wire clip: it is composed of an aluminum tube and steel anchor. Steel anchor is used to connect and anchor the steel core of the steel-core aluminum strand and then set on the body of the aluminum tube to pressure the metal to produce plastic deformation, so that the line clip and the wire combined as a whole, the use of hydraulic pressure, the application of the corresponding specifications of the steel mold to the hydraulic machine compression. The use of burst pressure can be used once burst pressure or secondary burst pressure, the wire clip and wire (overhead ground) pressed into a hole.

E. Wedge wire clip: used to install the steel strand, fasten the overhead ground wire and tie wire tower tie wire. It uses the splitting force of the role of the wedge so that the steel strand is locked in the line clip.

(2) connection of the gold class: connection of the gold is used between the insulator string and the tower, between the wire clip and insulator string, overhead ground wire clip and the tower for connection of the gold. Commonly used connection fittings have: ball head hanging ring, bowl head hanging plate, U-shaped hanging ring, right angle hanging plate, etc.

(3) jointing gold class: for the connection of the conductor and overhead ground wire connection, tension-resistant tower jumper connection. The stereotyped jointing fixture has: clamp pressure jointing fixture, hydraulic jointing fixture, bolt jointing fixture, burst pressure jointing fixture.

Hebei Yipeng Line Equipment Manufacture Co., Ltd. is a high-tech enterprise specializing in production, R&D and sales. Founded in 1995, the company is a professional manufacturer of electric power fittings, especially overhead line fittings and insulation fittings, composite insulators, lightning arresters, drop fuses, transmission and distribution and other electrical equipment products. If you want to buy high-quality overhead line fittings and so on, welcome to choose us.

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