Document Type : Original Article
Department of Industrial Engineering, Faculty of Engineering, Alzahra University, Tehran, Iran.
Department of Computer Engineering, Faculty of Engineering, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
The main aim of this paper is to emphasize on the significant role of data pre-processing phase in improving the short-term load demand forecasting. Different transformation approaches including normalization, Zscore and Box-Cox method are applied and various input selection methods including forward selection, backward selection, stepwise regression and principle component analysis are used to see how the combination of these pre-processing techniques will influence the performance of different parametric (ARIMA, ARIMAX, MLR) and non-parametric (NAR, NARX, SVR, ANFIS) predictors. The data was collected from the daily load demand of Ottawa, Canada. It was observed that the Box-Cox transformation significantly improved the performance of all predictors and the findings demonstrated the superior role of exogenous variables in accuracy improvement of all predictors. In terms of MAPE, the value of 2.27% for ARIMA model improved to 1.75% with ARIMAX using temperature, and it decreased from 1.46% to 1.334% by means of NARX model using normalized PCA which is applied on normalized data. In an overall view, the non-parametric algorithms had a considerable gain over parametric models and NARX network had the highest accuracy among all of the predictors.