GUI for the Analysis of Direct Flashover Shielding Failure in Overhead Power Lines

Abstract

The analysis of the performance of overhead power lines against the direct impact of lightning on phase conductors is a topic of interest in the field of transmission lines. The shielding failure flashover rate (SFFOR) measures this performance. The SFFOR is calculated after solving a set of complex equations, which may result in unintentional errors and require excessive computation time if the calculations are performed manually. In this study, a graphical user interface (GUI) was developed to compute the SFFOR. In contrast to existing similar tools, the developed GUI allows for the modelling of the probability density of the lightning current magnitude from historical data. In addition, the GUI can determine the optimal shielding angle. The equations for the SFFOR computation were obtained from the standard IEEE-1410 and -1253 and brochure 063 of CIGRE. The application of the proposed methodology to a 33 kV overhead power line located at 2700 m.s.n.m. indicated an SFFOR of 0.32 and 0.00 flashovers/100 km-year. The first result was obtained using the parameters of the log-normal function provided in the brochure 063. The second result considered the parameters of the distribution function determined by the proposed method. This shows the sensitivity of the results to the lightning current modelling. Both values were obtained in less than a second after entering the data into the GUI. Therefore, the developed GUI facilitates the analysis of the performance of power transmission shielding, allowing the evaluation of possible shielding improvements in a short time.