Rational design criteria for weather induced loads [overhead lines]

The complete break-through of the design methods on a probability basis has been prevented up to date by the lack of a suitable data basis and by the fact that the approximations employed in the calculations leave a large gap between the actual and the calculated risk of failure. Methods have been evolved for determining on a probability basis the weather-induced design loads of transmission lines, which permit the use of traditional meteorological observation data and their necessary supplementation. An extended programme of investigation has been conducted to perfect the methods of converting meteorological characteristics to transmission line loadings. The optimum return period of the design load-furnishing the lowest total costs-has been determined from an estimate of all costs expected during the lifetime of the transmission line. The relatively wide range of near-optimum solutions permits the introduction of other practical aspects