Diagnosis of Instrument Faults for Nonlinear Coordinate Systems

A new scheme for instrument fault diagnosis in nonlinear systems is presented. Since the basis functions of Laguerre filter are orthonormal, the parameters of filter can be converged rapidly and accurately. Hence, the plant can be modeled via Laguerre filter. The output of plant can be predicted according to the modeling plant, then the residual between the real output and predicted output can be obtained. Consequently, three kinds of instrument faults are diagnosed by analyzing the residuals. Finally the scheme is used to identify the instrument faults in a nonlinear boiler-turbine coordinate system, the simulation shows the results are satisfactory.