ANALYTICAL REPRESENTATION OF ELECTRICAL LOAD DURATION CURVE FOR OPTIMIZATION RESEARCH

Abstract

A method has been developed to restore the shape of the electrical load duration curve as the main predictive information on the demand for electric energy used in long-term and medium-term optimization studies of power systems. The main feature of the proposed method is the direct use in the algorithm of the basic coefficients characterizing the given form of the expression for energy demand, as well as a number of fixed points on the desired curve that are characteristic of the particular power system under study. The decision on the choice of fixed points is done with the help of retrospective historical statistics on the operation of the power system. The analytical polynomial expressions obtained using this method allow to quickly obtain the shape of the load duration curve and to simplify the procedure for entering the initial forms of curves in optimization programs, as well as to facilitate the process of predicting them for long time periods. The accuracy of the method was verified by comparison with the curves of past years obtained from the detailed hourly electrical load of the power system of the Republic of Belarus. It was found that the error value on the main part of the curve does not exceed ±1 % and slightly increases at its edges (±4–6 %), which is assumed to be sufficient accuracy for long-term energy planning.