Simulation of Transmission Grid Operation Incorporating Flexibility at Distribution Level

The ongoing structural changes in the power system are characterized by an increasing share of renewable energy sources, energy storages and demand flexibility in distribution grids. This is associated with growing interactions between transmission and distribution system operators and requires mechanisms to coordinate and exchange flexibility for providing ancillary services. This contribution analyzes the impact of flexibility of generation and storages at distribution level on the congestion management in the transmission grid. For this purpose, distributed flexibility is aggregated at high-voltage level and modeled as a separate energy storage system equivalent at each high-voltage node. The storage system equivalents allow temporal power shifts and are integrated in a congestion management simulation considering further grid-and market-related measures. The model is exemplarily showcased for a future scenario of the German energy system with a detailed representation of subordinate grid structures to analyze the impact of distributed flexibility on the congestion management in large-scale transmission systems. The results illustrate the high potential of distributed flexibility to contribute to congestion management and partially substitute conventional redispatch measures and the curtailment of onshore and offshore wind parks.