Dynamic Rating Analysis of Overhead Line Loadability Driven by Meteorological Data

Abstract

Traditional static thermal rating of overhead transmission line adopts combination of solidified and harsh meteorological parameters to calculate unalterable maximum thermal loadability and the calculation result is often conservative. Therefore, in this paper, a method of statistical analysis driven by meteorological data is used to convert constant annual loadability to seasonal or monthly loadability, and to shorten time scale of thermal rating. Based on CIGRE standard line thermal equilibrium equation, key meteorological parameters are determined with control variate method. Historical data of key meteorological parameters are analyzed statistically to determine thresholds for meteorological parameters and corresponding line thermal rating in a subset of meteorological data at different confidence levels and different time scales (monthly, quarterly, and yearly). Real annual meteorological data are used to analyze operational risk of thermal ratings. Results show that appropriate time scale, reasonable meteorological parameter confidence level and corresponding thermal rating can be easily determined according to allowed operational risk of power grids. Thermal rating of overhead transmission line driven by meteorological data improves loadability of the line.