Oscillation Suppression Strategy of Wind-thermal Bundled Delivery System Based on Accurate Locating of Optimized Controllers

With high proportion of renewable energy and high proportion of power electronic equipment, the traditional thermal power units have decreased. The structure and the operating state of the power system have changed significantly, leading to the reduction of the ability to operate stably under small disturbances. The wind-thermal bundled DC delivery system has the problems of multiple grid-connected units influencing each other and complex harmonic transmission, easily causing the small disturbance instability. In this paper, the small-signal stability of a multi-port system which has the characteristic of multi-input and multi output is analyzed based on the maximum peak Nyquist stability criterion. The grid-connected unit that plays a leading role in the system is studied, and an oscillation suppression strategy based on the accurate locating of the dominant controller is further proposed, suppressing the oscillation by fine-tuning parameter of the located controller. The effectiveness of the proposed method is verified by simulation cases.