Short Term Load Forecasting For An Interconnected Power System

Abstract

Accurate load forecasting is very beneficial for the efficient and economical operation of a power supply utility. The power system load forecast can be categorized into long-term forecast and short-term forecast. Long term forecast usually covers a time span of one year to ten years and is needed for decision making regarding capacity expansion and long term capital investment return studies. Short term forecast on the other hand provides information about system load characteristics from one hour to twenty four hours or upto a few days into the future. Short term forecast is necessary for the efficient and reliable operation of an electric utility. It is needed for economic dispatch, unit commitment, energy sale/purchase decision and load management. Keeping in view the importance of accurately forecasting the system load an improved algorithm has been developed for short term load forecasting of an electric utility. In this perspective the approach adopted is based upon time series analysis. Emphasis is on modeling the interconnected power system in state space form. Stochastic Approximation algorithm and Kalman Predictor are applied for load forecasting upto one hour. A software package is developed with the proposed implementation method for electric supply utilities. The application of this software package to real load data obtained from WAPDA (Water and Power Development Authority) has shown good results. The salient feature of this software package is that it can provide a breakup of load demand at each grid station, which is not currently available with WAPDA. This breakup can result in reduced transmission losses with corresponding economic benefits.