High-dimension tie-line security regions for renewable accommodations

Tie-line power exchanges among regional power systems facilitate renewable accommodations. Power exchanges can be calculated based on a tie-line security region that provides the feasible region of coupling parameters. However, a tie-line security region is a high-dimension polytope due to multiple time periods and border buses in power system operations, generally leading to a heavy computational burden. A fast calculation for high-dimension tie-line security regions is studied in this paper. The high-dimension polytope across all the time periods is decomposed as a Cartesian production of lower-dimension polytopes at each time period by leveraging dispatch levels of generations. For each lower-dimension polytope, the computational burden brought by multiple border buses is alleviated by aggregating tie-line power. Minimum renewable curtailments are preserved in the tie-line security region by adding an additional dimension, providing the information for renewable accommodations based on the tie-line security region. For coupling parameters within our tie-line security region, a feasible decision of the regional power system always exists. Finally, a decentralized and non-iterative framework is demonstrated to utilize our tie-line security region for renewable accommodations in an interconnected power system. The effectiveness of our methods is corroborated in the IEEE 9-bus system, a 661-bus utility system, and a five-region system.