Non-linear modelling and stability analysis of the PTGS at pump mode

Abstract

© 2017 The Institution of Engineering and Technology. For the sake of studying the stability of the pumped storage power station, the authors focused on the mathematical modelling of the pump-turbine governing system (PTGS) at pump mode. First of all, six transfer coefficients were introduced into the model of the pump-turbine. Furthermore, utilising the internal characteristics formulas, they obtained six analytical expressions of the transfer coefficients at pump mode. Considering the elastic water-hammer model of the penstock with hydraulic friction and the second-order model of the generator, a non-linear model of the PTGS was proposed. On the basis of a real case, they obtained the curve of bifurcation points of the system by using the stability theorem, and verified the correctness of the theoretical analysis results from numerical experiments. Moreover, the stable domains of the proportional-integral- derivative parameters kp and kd were identified and the non-linear dynamic behaviours of the governing system were studied. Finally, these methods and analytic results could help them improve the safety operation and performance of the pumped storage power station.