Dynamic behavior of combined 100% IBR transmission and distribution networks with grid-forming and grid-following inverters

Abstract

A new era of the electrical grid began due to the high integration of the inverter-based resources. Typically, resources are connected to the electrical grid using grid-following control techniques. Overall system inertia reduces as these resources replace rotating synchronous machines. Grid-forming control is one of the solutions introduced to overcome the challenges in the electrical grid due to the increase in inverters. With the increase of inverter-based resources in both transmission and distribution networks and the introduction of new inverter controls, it is important to understand how power system voltage and frequency dynamics are affected. In this paper, a 100% inverter-based resource electrical network is studied across both transmission and distribution networks while considering different inverter control configurations and different methods of current limiting. Moreover, the increasing penetration of inverter-based resources poses challenges to transmission planning as the dynamic interaction between distribution and transmission can no longer be ignored. In this regard, an aggregated distribution network model is proposed for transmission planning studies to accurately represent the distribution network's dynamic behavior at different grid-forming and grid-following inverter ratios.