The Study On The Identification Of The D-axis Transient Open Circuit Time Constant And Its Application

With the application of modern power technology used in the power system,more and more process of the power system needs to be identified to provide areference for operation, control and forecasting and so on. Therefore, it is verynecessary to research the power system identification in both theoretical significanceand practical value.This paper researched the identification of the d-axis transient open circuit timeconstant of synchronous generator, which is the core components of the powersystem , With the identified model used in the electrical braking of shut downprocess of the synchronous generator sets. This paper briefly introduced theapplication and development of the identification of the d-axis transient open-circuittime constant. In order to identify the parameters accurately and efficiently, Theelectromagnetic and voltage equation of synchronous generator in no-load conditionswas analyzed and the mathematical model of the synchronous generator, whichcontained the main parameters and variables such as the terminal voltage, theexcitation voltage, the excitation current，the d-axis transient open circuit timeconstant and the excitation time t in the excitation test, was derived. It got the actualmeasured data by the MATLAB SIMULINK simulation platform to build synchronousmotor excitation test simulation model and the parameter identification of d-axistransient open circuit time constantT’_d0was done by the least square method,simulation results show that the mathematical model derived scientific and the leastsquare identification method affection.In addition, according to the problem of how to determine the size of the brakingcurrent of the synchronous machine stator of the winding three-phase short-circuitelectrical braking，The electrical braking time-tested platform was developed by thehybrid programming between MATLAB and VB to investigate the application of thebraking current of the excitation in the electric braking，which was obtained by theidenfied mathematical model of synchronous generator above.