EMT simulation of transmission systems and CIG-dominated distribution feeders

The ever-increasing share of distributed electric power generation in feeders requires adopting models of both transmission systems and active distribution feeders, which lead to a staggering increase in the total number of power grid buses/equations and of the simulation effort. We propose a numerical method that exploits a new formulation of the frequency-shifting transformation (carried out on a phase-by-phase basis), dynamic phasors, circuit partitioning, and parallel execution of multiple-threads. Overall, these solutions grant a boost in simulation efficiency of up to two orders of magnitude with respect to existing approaches. After proving this claim by simulating a relatively small benchmark with our proposed method and a commercial power system simulator, we show that the method can be efficiently used to run three-phase electromagnetic transient simulations of large-scale power systems. As a test benchmark, we picked the wnaps transmission system, modified by adding several replicas of the ieee 8500-bus feeder, each equipped with hundreds of converter-interfaced generators.