NOX EMISSION MODELING USING THE ITERATIVELY REWEIGHTED LEAST-SQUARE PROCEDURES

NOx emission dispatching is a method to reduce the amount of oxide of nitrogen produced by thermal generating units to meet given power demands. This requires adequate models relating NOx emissions to the active power generation of the unit. Least-squares estimation procedures work best when measurement errors are Gaussian. For the non-Gaussian errors and Gaussian errors, the iteratively reweighted least-squares (IRWLS) procedure with optimized weight functions and their associated weight constants can be used to estimate, refine and fine tune parameters of identified models. The form of the emissions model is restricted to those with monotonically increasing derivatives due to subsequent minimization process requirements. We explore the application of some transformations to the form of model chosen. Moreover, emission models ale developed using the IRWLS procedure. The results obtained using the iteratively reweighted least-square procedures are compared with the least squares.