Enhanced Design of Wind Protection for 500 kV Overhead Transmission Lines in Coastal Strong Wind Areas

Abstract

[Introduction] With the increasing frequency of extreme weather in China's coastal areas, typhoon disasters pose a great threat to coastal power grids, in order to improve the lines wind protection ability, the design of coastal strong wind area lines usually take to improve the design of the meteorological return period, with the promulgation of the current standards of overhead transmission lines (DL/T 5551－2018), due to the differences in wind load calculation between the new and old codes, the compatibility of the previous wind reinforcement measures with the current code has become an urgent issue to be studied. [Method] This paper took the 500 kV important lines in the coastal strong wind area of the southern power grid as an example, and based on the grading system of wind protection reliability of lines, by formulating different wind protection design schemes, and then evaluating the level of wind resistance and reliability under different schemes, and comparing the technology and economy under different defense schemes, finally, combined with the engineering examples, it recommended the wind protection design scheme for 500 kV important lines in coastal strong wind areas. [Result] Under the premise of implementing the current standards, designing according to the 50-year return period wind speed and considering 1.1 times the importance coefficient (the third option) and the previous design based on GB 50545－2010 according to the 100-year return period, both in the wind resistance and engineering investment can be a good fit. [Conclusion] The third option is the choice of the best combination of technical and economic indicators among the fortification options and the wind-resistant capacity can reach the requirement of the medium limit of 16-stage typhoon, which is of great significance for saving resources and reducing carbon emissions.

Keywords

• coastal strong wind zones
• overhead lines
• reliability classification
• wind resistance
• windproof design