Unified Sensitivity-Based Heuristic for Optimal Line Switching and Substation Reconfiguration

TL;DR

This paper introduces a unified sensitivity-based heuristic for optimal transmission reconfiguration that combines line switching and bus splitting, leading to significant economic benefits in power system operation.

Contribution

It formulates a new OTR problem incorporating bus splitting, develops a sensitivity framework, and demonstrates its effectiveness through extensive simulations.

Findings

Incorporating bus splitting yields greater cost savings than line switching alone.

The proposed sensitivity method is highly effective across various IEEE test systems.

Unified treatment of line switching and bus splitting simplifies analysis and enhances reconfiguration strategies.

Abstract

Optimal transmission switching (OTS) determines which transmission lines to remove from service to minimize dispatch costs. Unlike topology design, it alters the operational status of operating lines. Sensitivity-based methods, as advanced optimization techniques, select lines whose outage yields a significant cost reduction. However, these methods overlook bus splitting, an effective congestion management strategy that our work incorporates to achieve improved economic gains. In this work, we formulate an optimal transmission reconfiguration (OTR) problem that incorporates both line switching and bus splitting. We develop a novel approach to quantify the sensitivity of the OTR objective to line switching and bus splitting, establish connections between the proposed sensitivity framework and existing heuristic metrics, prove the equivalence between bus splitting and a generalized line switching to enable unified treatment, and provide a simpler derivation of Bus Split Distribution Factor (BSDF). Simulations on nine IEEE test systems spanning 118 to 13,659 buses demonstrate the high effectiveness of our proposed sensitivity method. They also demonstrate that incorporating bus splitting into transmission reconfiguration achieves greater cost savings than line switching alone. The results confirm the economic advantage of this comprehensive approach to transmission system operation.