Dynamic Equivalent of Ibr-Dominated Distribution Networks Through Multi-Port Synthesis

Distribution networks (DNs) are shifting from passive to active due to an ever-increasing share of inverter-based resources (IBRs), whose simulation is computationally demanding. To address this issue, we propose a DN reduction method that boosts simulation efficiency in two steps. First, the DN is synthesized as a multi-port circuit, with one port at the substation downstream of the transmission grid, and one for each gridfollowing IBR connected to the DN. Second, IBRs with a similar voltage dependency are clustered, and only a representative IBR per cluster is retained in the reduced DN. The method is compatible with DNs of any size (be them balanced or unbalanced, three-phase, single-phase, with or without neutral) and clusters IBRs through a numerical approach that hinges only on power flow and small-signal analysis. Thus, it is agnostic to the IBR model used and can suitably group IBRs with different power set-points and ratings. Simulation results of the IEEE 8500 node DN prove the accuracy and CPU time speed-up of the method.