Minimal Reduction of Unscheduled Flows for Security Restoration: Application to Phase Shifter Control

Abstract

More and more transmission system operators, noticeably in Europe, equip their systems with phase shifting transformers to counteract transit flows that take place in a large meshed interconnection. This paper proposes algorithms for the coordinated control of several phase shifters by one operator with the objective of reducing the unscheduled flow through its system. Minimum reduction of unscheduled flow and minimum deviation with respect to present operating point are sought in order to minimize the trouble caused, while ensuring secure operation. Attention is paid to combining pre- and post-contingency controls. The resulting algorithms, simple and compatible with real-time applications, are illustrated on a realistic test system.