Analysis of ultra-low frequency oscillation mechanism of hydraulic turbine governor under different control modes

Abstract

As the southwest power grid with a high proportion of hydropower was transformed into UHV AC-DC network structure, some ultra-low frequency oscillations have appeared in the power grid. In this paper, according to the characteristics of the hydropower unit governor, a small disturbance model was established, and the influence of various parameters of the hydropower unit governor on the system stability in primary frequency modulation was discussed by using the eigenvalue analysis method, and the power mode and the opening mode were compared. The results showed that the parameter adjustable range of the opening mode was larger than that of the power mode. This paper lays a foundation for further research on suppression methods of ultra-low frequency oscillations.