FORECASTING LOAD-DURATION CURVES

A new method is proposed for forecasting electricity load-duration cur ves. The approach first forecasts the load curve and then uses the res ulting predictive densities to forecast the load-duration curve. A vir tue of this procedure is that both load curves and load-duration curve s can be predicted using the same model, and confidence intervals can be generated for both predictions. The procedure is applied to the pro blem of predicting New Zealand electricity consumption. A structural t ime-series model is used to forecast the load curve based on half-hour ly data. The model is tailored to handle effects such as daylight savi ngs, holidays and weekends, as well as trend, annual, weekly and daily cycles. Time-series methods, including Kalman filtering, smoothing an d prediction, are used to fit the model and to achieve the desired for ecasts of the load-duration curve.