Spiral welded pipes for gas insulated transmission lines

Abstract

The invention discloses a spiral welded pipe for gas insulated transmission lines, which comprises a welded pipe body, wherein the welded pipe body is of a circular pipe structure welded by curling a sheet strip in a spiral manner, the outer diameter D of the welded pipe body is 800mm-910mm, and the pitch T of a spiral welding seam on the welded pipe body is 1.8m-2.5m; the ratio V / D between the rated voltage V of the welded pipe body and the outer diameter D of the welded pipe body is 0.90KV / mm-1.25KV / mm; the ratio t / D of the roundness t of the welded pipe body and the outer diameter D is 0-1.5 / 1000, and the straightness f of the welded pipe body is 0-1.5mm / m. The spiral welding seam on the welded pipe body is a double V-shaped butt joint welding seam. The pipe wall thickness of the welded pipe body is 8mm-10mm. The spiral welded pipe not only can keep uniform electric field distribution, but also is convenient to manufacture and process; and the spiral welded pipe is especially applicable to ultra-high voltage and extra-high voltage gas insulated transmission lines.

Description

technical field [0001] The invention relates to the technical field of ultra-high voltage and ultra-high voltage power transmission, in particular to an outer shell sleeve of a gas-insulated metal-enclosed power transmission line. Background technique [0002] Gas-insulated metal-enclosed transmission line is a kind of SF 6 Gas-insulated, high-voltage, high-current power transmission equipment with coaxial arrangement of shell casing and conductor, as a large-capacity, high-voltage, long-distance transmission line, compared with high-voltage cable transmission lines and overhead lines, it has high reliability, It has many technical performance advantages such as strong transmission capacity, low loss and long service life, and is especially suitable for substations, nuclear power plants, large hydropower plants and underground ultra-high voltage transmission networks. [0003] SF filled between the shell sleeve and the conductor 6 It is a new generation of ultra-high volta...

AI Technical Summary

Problems solved by technology

[0005] At present, the transmission voltage and pipe diameter of casing and casing are still limited within a limited range, which greatly restricts the application range of gas-insulated metal-enclosed transmission technology.

At the same time, in order to reduce the weld length of the shell sleeve and avoid the leakage of insulating gas, most of the existing shell sleeves adopt the structure of longitudinal butt welding of metal plate rolling. Although this structure can control and reduce the weld length, the pipe section The length is limited by the length of the plate and the width of the rolling equipment, which increases the number of connecting pipes in the transmission line and the number of connecting structural parts between adjacent pipe sections. There are more gas leakage points; especially this kind of longitudinal welding structure is difficult to ensure the roundness of the shell casing, which is easy to cause the casing out of roundness, and the roundness of the shell casing with such a large diameter is difficult to correct, giving the The uniformity of electric field distribution in use leaves hidden dangers

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