Generalized Discrete-Time Equivalent Model for Representing Interfaces in Wide-Area Power Systems

Area control centers can effectively utilize the dynamic model of wide-area power systems when large power system areas are subjected to major disturbances. However, as the modeling of individual areas could be performed at different time scales, the boundary power flows between areas may not satisfy power system conditions as individual equivalent area models are merged to represent the wide-area system. In this paper, individual areas are represented by a generalized discrete-time equivalent model (GDEM). In particular, this paper considers the impact of modeling interfaces (MIs) for linking several GDEMs in which boundary power flows would be considered exclusively when individual area models are merged. The practical use of MI in GDEM is to represent widely-encountered power transfer paths in the Western Electricity Coordinating Council, including a two-area radial system for the Washington-Montana flow, and a three-area star-connected system for the Pacific AC Intertie. Based on the detailed two-area radial system and three-area wyeconnected system, we propose a generalized framework for an n-area connected system. The China Electric Power Research Institute system is also studied to verify the application of the proposed method which shows the use of MI in GDEM for analyzing the dynamic characteristics of wide-area power systems.