A Modelica IBM Implementation for Fast Simulation of Digital Controllers in Power Systems

The behaviour of modern power systems is more and more dictated by smart digital controllers responsible for ensuring the security, optimal operation, and stability of the systems. For the development, testing, and validation of these controllers, it is necessary to model and simulate different scenarios in power system dynamic analysis. However, digital controllers introduce discontinuities during the dynamic simulation that force the solver to reduce the time step taken to land on the discontinuity and restart the simulation. Therefore, the simulation of systems containing many digital controllers becomes very time-consuming. The Interpolation-based method (IBM) provides a fast but accurate approach for the dynamic simulation of power systems with multiple digital controllers without the need to reduce the time steps. This paper presents a fixed-step implementation of IBM in Modelica that allows to embed this method in the Modelica controller model without the need to modify the solver algorithm. The performance of the method is showcased on a single-machine infinite-bus test system.