Coordination of transmission path transfers

The transfer capability on a transmission path is limited by constraints on acceptability, voltage security, small-signal stability, and transient stability. For a large interconnected power grid, these constraints are influenced significantly by the interactions among path flows in different control areas. When a critical transmission path capability is limited by one of these constraints, it may be necessary to coordinate the interarea power transfers so as to improve the transfer capability on the constrained path without compromising on the security criteria. Based on such considerations, this paper presents a novel multiobjective methodology in which global strategies are developed for the improvement and coordination of transmission path transfers. The problem is formulated with respect to various constraints into suitable optimization problems. An efficient nonlinear programming algorithm with sufficient line search step is incorporated for finding optimal solutions while also incorporating security and stability constraints. The MW benefits for the transfer capability from the coordination procedure are explicitly demonstrated after the optimization process. The effectiveness of the methodology is illustrated by case studies on improving the capability of the California-Oregon Intertie (COI) for large-scale WECC western American power system models.