A Novel UPFC Model and its Convexification for Security-Constrained Economic Dispatch

• Published in: IEEE transactions on power systems Vol. 37; no. 6; pp. 4202 - 4213
• Main Authors: Wu, Xi, Wang, Rui, Wang, Yifei, Wang, Liang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: binary expansion method; Constraints; Economic models; Load flow control; Mathematical models; Mixed integer; mixed integer second-order cone programming (MISOCP); Physical properties; Power flow; Power generation dispatch; Power system security; Preventive security-constrained economic dispatch; Security constrained power dispatch; Sensitivity analysis; Taylor series; three-terminal power injection model; unified power flow controller (UPFC); Voltage control
• ISSN: 0885-8950; 1558-0679
• DOI: 10.1109/TPWRS.2022.3148090

Unified power flow controller (UPFC) gains growing application in power systems due to its power flow regulation ability. However, there is still a dilemma in the incorporation of UPFC into security-constrained economic dispatch (SCED). The modeling of UPFC involves nonlinear and nonconvex operational constraints, which is difficult to solve efficiently and accurately. Conventional methods adopted Taylor expansion or sensitivity analysis to realize the convexification of UPFC models, which leads to a loop structure and is subject to initial point choice. In this paper, a novel three-terminal injected UPFC model is proposed. In the proposed model, the voltage source variables are eliminated completely. Instead, only power injection variables are introduced to equivalently describe physical characteristics and constraints of UPFC. The nonlinear and nonconvex operational constraints of UPFC are transformed into mixed integer second-order cone form. Moreover, compared with conventional UPFC models, the control characteristic of UPFC is considered in a more accurate and practical manner in the proposed SCED, which helps to prevent potential risks of power flow over-limit under N -1 contingencies. Simulation results show the effectiveness and efficiency of the established solution.