Introduction of damping, synchronizing and inertial effects using controlled power injection devices

This paper presents a theoretical study of damping, synchronizing and inertial control laws, implemented using controllable power injection devices like HVDC, FACTS or renewable-energy/storage systems which have power-electronic grid interfaces. The approach is to use a simplified dynamical model of a power system to arrive at generalized results regarding the effect of the strategies on the electro-mechanical dynamics of the system. These results are not dependent on the size, network topology and operating condition of the power system. This paper presents a differential-algebraic formulation and generalized eigenvalue analysis to facilitate a unified study of the effects of the control laws on the electro-mechanical modes. The damping, synchronizing and inertial control laws can themselves be extended to include the possibility of mutual-damping, synchronizing and inertial effects when multiple devices are present. The control laws are not only simple and intuitive, but also are found to have a predictable and generally beneficial impact on the electro-mechanical dynamics of the grid, even when detailed models are considered.