Research On The Identification Of Synchronous Generator Parameters Based On GPS-PMU

Valid synchronous generator parameters play a very important role in the stability analysis and short-circuit calculation of power system. In this paper, the research work on the synchronous generator parameter identification is based on GPS-PMU. Taking the composite stability model as its research object, the following questions are investigated:(1) Some of power angle measurement methods are analyzed, considering the power angle measured by the method based on the rotate speed signal can be used in the synchronous generator parameter identification. The theory of identification based on GPS-PMU is described. Transfer equations between the data measured by GPS-PMU and the data used in the identification are deduced. The parameter identification flowchart is given. The simulation illustration shows that the data measured by GPS-PMU can satisfy the requirement of identification.(2) The identifiability of OLFR method is studied, several conclusions are given. Parameters in q-axis can be identified uniquely. For parameters in d-axis,Xd and X"d can be identified uniquely, the identifiability of other parameters dependon the real condition.(3) OLFR and time-domain identification method are compared. For steady-state parameters, both methods have good accuracy. For transient-state parameters in q-axis, OLFR does better than time-domain method. For transient-state parameters in d-axis, Time-domain method does better than OLFR. Altogether, the sampling rate at 50Hz can not satisfy the identification of sub-transient parameters in d-axis by OLFR method. If the frequency-domain information is rich, the OLFR method can be used, but the identifiability problem should be cared.(4) An improved load rejection method for parameter identification based on the power angle measured is advanced. On the condition of power angle measured, taking field current, terminal voltage and rotate speed as measured quantity, the whole parameters in d and q-axis can be identified through a load rejection test under an arbitrary reference.(5) All the simulation results in this paper are compared. For steady-state parameters, all the results show good accuracy. For transient-state parameters, as the disturbance manner referred to, the load rejection test gained the most accurate parameters, the step disturbance in excitation voltage lies in the second, the outer disturbance lies in the last. As the identification methods referred to, time-domain method does better than frequency-domain method as a whole, but the OLFR can not be excluded if the frequency-domain information is rich. In a word, the selection of disturbance manner and the selection of identification methods are the same important to the synchronous generator parameter identification.