  In this paper, we propose a combined Online Feedback Optimization (OFO) and
dynamic estimation approach for a real-time power grid operation under
time-varying conditions. A dynamic estimation uses grid measurements to
generate the information required by an OFO controller, that incrementally
steers the controllable power injections set-points towards the solutions of a
time-varying AC Optimal Power Flow (AC-OPF) problem. More concretely, we
propose a quadratic programming-based OFO that guarantees satisfying the grid
operational constraints, like admissible voltage limits. Within the estimation,
we design an online power flow solver that efficiently computes power flow
approximations in real time. Finally, we certify the stability and convergence
of this combined approach under time-varying conditions, and we validate its
effectiveness on a simulation with a test feeder and high resolution
consumption data.
