An improved bus aggregation technique for generating network equivalents

The requirements of a network equivalent to be used in a planning tool (such as the SuperOPF being developed at Cornell) for analyzing policy options, impacts on reliability, costs and emissions for networks as vast as the entire Eastern Interconnection, are very different from those assumed in the development of traditional equivalencing procedures. In this paper, a novel network equivalencing approach using bus aggregation techniques is proposed that shows promise for modeling such large systems in the context of analyzing policy options and emissions. This approach is superior to the existing bus aggregation methods in that a) under the base case, the equivalent-system inter-zonal power flows exactly match those calculated using the full-network-model b) as the operating conditions change, errors in line flows are minimized c) the method is more computationally efficient than other bus aggregation methods proposed heretofore. The proposed method is tested on an illustrative six-bus system and promising results are observed.