New challenges for forecasting voltage sags due to lightning phenomena in distribution networks

Voltage sags cause severe problems in distribution systems, resulting in huge economic losses; they may occur due to overvoltages and short circuits caused by lightning phenomena. The proposed research aims at developing a tool to forecast, with an adequate lead time, the main characteristics of the voltage sags caused by lightning phenomena in active distribution networks. The development of the tool requires methods for supporting decisions under uncertainty, the short-term forecasting of lightning affecting distribution systems and the modeling of: i) the lightning overvoltages and flashovers on overhead lines; ii) the line insulation withstanding characteristics to lightning overvoltages; iii) the impact of distributed generation contribution in short-circuit operating conditions; and iv) the voltage sags characteristics. All tasks are considered and described in this paper.