Combined Optimization of Steady-state Operation and Small-signal Dynamics in Hybrid AC/DC Power Systems

This paper presents an approach for calculating optimized operating conditions in hybrid AC/DC systems while considering constraints on the small-signal dynamics. The implementation is based on a closed form power flow optimization considering the steady-state operating conditions and the damping of the eigenvalues calculated from a linearized system model. The optimization utilizes the eigenvalue parametric sensitivities to calculate the next time steps' operating points. The small-signal modelling for the calculation of the eigenvalues and their sensitivities are based on a modular approach that facilitates the scalability to larger systems. An implementation in AMPL and Matlab is presented to assess convergence and computational performance. Finally, the methodology and the software implementation are validated numerically on an example hybrid AC/DC system with a multi-terminal HVDC grid. Simulation results show that the combined optimization allows to improve the steady-state operating point according to dynamic system behaviour.