Optimal power flow including voltage stability

This thesis investigates the effects of including a voltage stability index as part of Security Constrained Optimal Power Flow (SCOPF). The formulation of Optimal Power Flow (OPF) and SCOPF, and their computational features are discussed. Different types of voltage stability indices are studied and an L-index based voltage stability index is used for the investigation. Two different approaches are used in formulating the L-index in SCOPF. In one method, the L-index was formulated as a part of SCOPF constraints. In the other, the L-index is used as the SCOPF objective function. The effects of these methods on the voltage stability of the system are determined by monitoring the voltage stability margin. Simulation results based on the two methods are presented for a 6-bus system and 30-bus system. The advantages and disadvantages of both the methods are discussed. Simulation results indicate that the method with L-index as SCOPF objective function significantly improves the voltage stability margin compared to the standard SCOPF.