Application of Recursive Least Squares Method for Parameter Identification of DEH Governing System

Abstract

Parameters identification of the governing system model has great importance for the analysis of electric power system stability. The tranditional mechnical hydraulic governing systems were studied early. Now the digital electric-hydraulic(DEH) governing system is employed for large-scale steam turbine usually. So the dynamic characteristic of double-reheat steam turbine and its govering system model should be studied based on parameter identification. For its simple principle and well estimation performance, the recursive least squares (RLS) method was employed to make the parameter identification in this work. The DEH-III A governing system model of a 300MW unit is constructed using transfer function method. Butterworth low-pass filter was applied to avoid the disadvantage of off-band signal and improve the identification precision. Also the design parameters of Butterworth low-pass filter were discussed. The calculation results based on the disturbed test data of a 300MW unit were listed using the set matlab program. And the curves of model outputs and measurement values of identification module were consistent. The calculation results showed that the RLS method has a high speed and it was efficient for parameter identification of complicated objects.