Stability of multi-hydro-turbine governing time-delay systems with sharing tailrace surge tank

In this paper, we focus on the stability of the hydropower plant with sharing tailrace surge tank. Considering the interaction between hydro-turbines and time-delay of hydraulic servo system, a nolinear dynamic model of multi-hydro-turbine governing time-delay systems with sharing tailrace surge tank is first established. The model can predict the transient characteristic of the hydro-turbine governing system, promoting the development of transient analysis, and safe operation of the governing system. Then, bifurcation characteristics of the system with different governor parameters and time-delays are studied. Moreover, the effect of time-delay on the stability intervals of governor parameters are investigated and its optimal value with different time-delays are obtained. All of the above analytical results can provide theoretical guidance for the actual operation of a hydropower plant with sharing tailrace surge tank.