Development of reduction program for bulk power system stability study

Reduction of a power system provides an effective tool to efficiently analyze its stability, among others, bulk power system models. This paper proposes a practical reduction method for power systems. The principal feature of the proposed method, which is based on a coherency technique, is its capability to match a short-circuit current after the reduction of the power system to that of the original system and to reduce any radial or loop sub-system. A zero-sequence network can be also reduced in parallel. Usefulness of the reduction method has been verified through its application to a test system.