Tie-line Security Regions in High Dimension for Renewable Accommodations

TL;DR

This paper introduces a fast, decomposition-based method to compute high-dimensional tie-line security regions, enabling efficient renewable accommodation and reducing curtailments in interconnected power systems.

Contribution

It proposes a novel decomposition approach that simplifies high-dimensional security region calculations by leveraging dispatch levels and tie-line aggregation.

Findings

Method reduces computational burden significantly.

Effective in multiple test systems including IEEE 9-bus and 661-bus.

Helps in minimizing renewable curtailments.

Abstract

Tie-line power exchanges among regional power systems facilitate renewable accommodations. Power exchanges can be calculated via a tie-line security region that provides the feasible region of the coupling parameters among regional power systems. However, a tie-line security region is a high-dimension polytope due to multiple time periods and border buses inherently in power system operations, leading to the considerable computational burden. A fast calculation method for tie-line security regions in high dimension 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. Also, minimum renewable curtailments are preserved by incorporating an additional dimension in the tie-line security region. For the coupling parameters located within our tie-line security region, a feasible decision of the regional power system exists. Finally, the tie-line security region is used to reduce renewable curtailments in an interconnected power system under a decentralized and non-iterative framework. The performance of the presented methods is corroborated in the IEEE 9-bus system, a 661-bus utility system and a five-region system.