Probabilistic analysis of total transfer capability considering security constraints

Total transfer capability (TTC) indicates the power transfer capability among different systems or different subsystems. TTC is limited not only by the violation of system thermal and voltage limits, but also restricted by transient stability limits. Due to the uncertainty of power system behavior, it is impossible to give a fixed TTC results under all conditions. Specifically, in system operation, transmission risk analysis needs a statistical forecast for an expected range of transfer capability. It is, therefore, worthwhile to study the TTC problem from a probabilistic point of view. In this paper, an algorithm to incorporate security constraints in calculating TTC is proposed. Monte Carlo simulation is used to accomplish the probabilistic calculation of TTC with consideration of stochastic features of transient stability. The WSCC-9 bus system is used as the test system to demonstrate the methodology