A Smart Power Flow Adjustment Method with Phase Shifting Transformers for Long Term Generation Outages

This paper assumes significant amount of protracted local loss of the generation capability (approximately 20% of the total capacity), and examines the resulting load changes in the loop system, which likely result in creating considerable power flow differences in such a system. We then propose the use of phase shifting transformers (PSTs) to alleviate load differences among transmission lines, allowing more effective use of the loop system. Specifically, we propose the concept of active power flow sensitivity (APFS) and active power flow sensitivity 2 (APFS2). By installing and operating PSTs at optimal locations with proper phase angles, which are determined by a branch and bound method, we mitigate load differences between heavily and lightly loaded transmission lines. The validity of the proposed method is confirmed by using a modified IEEJ EAST 30 model.