Interactions among Limits during Maximum Loadability and Transfer Capability Determination

The main idea of this paper is to illustrate the interaction between various kinds of power system operational limits and corrective actions. In particular, the paper focuses on the interplay between line flow limits and active generation redispatch as the corrective action. The proposed methodology handles a wide range of flow limits by explicit inclusion of line flow equations into the set of the system model equations. Four options for active generation redispatch are discussed. The applicability of the methodology in deregulated environments for operating a power system within its security constraints by Security Coordinators or Transmission Providers is discussed. The power system model is based on a computationally efficient point of collapse power flow for tracing steady state behavior due to slow system parameter variations. Results of tests obtained with help of the IEEE-39 and IEEE-118 bus systems are given to illustrate the performance of the proposed methodology.