Power Supply Reliability Assessment in UPFC-installed Transmission System for ATC Enhancement Considering Transient Stability

With recent development of power electronics technology, power system stability enhancement and optimal power flow control by using Flexible AC Transmission System (FACTS) devices have so far been studied. The FACTS devices to relieve multiple constraints can also make it possible to enhance Available Transfer Capability (ATC) without construction of new transmission lines. The previous research revealed that ATC is expanded by avoiding multiple constraints in OPF using Unified Power Flow Controller (UPFC). For long-term operation of such ATC-expanded power system, it is necessary to evaluate power system reliability. In this paper, the evaluation method of supply reliability for UPFC-installed power system is proposed. Both thermal capacity and transient stability constraints are considered. The effectiveness of the proposed method is shown by numerical examples for IEEJ East10-machine test system.