Finding congestion modes of future grids with diverse power exchanges

Future power exchange scenarios will become more diverse as more renewable generation, energy storage, and flex-ible loads get integrated into market-dispatched power grids. Transmission network expansion planning (TNEP) practices must be updated to consider the resulting diversity of power in-jection scenarios in the future. In previous work, we quantified grid adequacy to host diverse power exchanges by characterizing the power flow infeasible set. We did this in the context of TNEP to help in the preliminary assessment of existing grids and in the identification of network expansion interventions that help improve grid adequacy. In this work, we present another approach to characterize the infeasible set using what we call grid congestion modes. We visualize how these modes arise from the constrained DC power flow problem and present a method to find them in small- to medium-sized power grids. Case studies using a six-bus test system and a reduced approximate model of the Philippine Luzon grid illustrate the benefits of this approach in TNEP: (1) give insights on grid bottlenecks when power ex-change scenarios become more diverse and (2) identify power exchange scenarios that trigger different congestion patterns that can be used in TNEP.