Towards a Transmission Line Limit Preserving Algorithm for Large-Scale Power System Equivalents

Power system equivalents have long been used for reducing the size of power systems networks. While there are a number of equivalencing methods, little attention has been paid on how to retain thermal line limits from the original system. This paper presents an approach to develop an equivalent network for a large scale power system that preserves the thermal line limits from the equivalenced lines. The proposed method is able to assign limits to equivalent lines with inexpensive computation and is operating point independent even with a loaded system. The algorithm is applied to create a backbone type equivalent system of the Eastern Interconnection in North America.