On the Forecast of the Voltage Sags: First Stages of Analysis on Real Systems

This paper refers to the voltage sags, which are among the most critical Power Quality disturbances. Thanks to the availability of measured voltage sags for four years in the same regional electric system, the work is our first attempt of using the registered voltage sags in three years for forecasting the expected voltage sags in the fourth year. The approach of the paper follows that proposed very recently by the professor M.T. Correia de Barros. Several intermediate results are similar to those obtained by her researches. The final results in terms of forecasts reveal that some improvements are needed for obtaining predictions with increased precision. The paper also presents the first improved results.