Main Article Content
Short term load forecasting is one of the fundamental parts of the electric system. Among exponential smoothing methods, the Holt-Winters method is widely used to forecast the short-term load since it is easy and simple to use, and it has high ability to adapt to the forecast of different time horizons. This paper presents a new approach by combining Holt-Winters and Walk-Forward Validation methodology to forecast the maximum power demand for Ho Chi Minh City, Vietnam. The data is divided into the training and test sets in many cases. The forecast accuracy of the mean absolute error (MAE) and the mean absolute percentage error (MAPE) are used to analyze the characteristic of forecast for each day of the week.