A Fitting Method of Fault Transient Signal in Power System

A new fitting method of fault transient signal in power system is proposed based on shifted Legendre polynomial. Compared with the existing fitting methods, this new method can directly develop the nth derivative, instantaneous amplitude and instantaneous phase of the fitted fault transient signal, and at the same time can reflect the attenuation characteristic of the fault signal. In this paper, basic concepts and principles of modeling, fitting and Legendre polynomial are firstly introduced. Secondly, the establishment of the new model and its three important characteristics are analyzed. Finally, the validity and accuracy of the method are verified by two simulation test signals as well as the field fault signal.