Reliability evaluation of composite systems considering voltage stability problems

A new approach to evaluate reliability indices of composite system considering voltage stability based on Monte-Carlo simulation is presented. The adequacy analysis of each selected system state is carried out in two steps. In the first one, an optimal power flow, solved by a direct interior point (IP) method, is adopted to calculate the static voltage stability limit including maximum load and voltage limits in power systems. If the voltage instability occurs, the voltage limits are saved. In the second step, adequacy indices are evaluated considering changed load limits and voltage limits. A new software is developed based on the method mentioned above. Test of a 24-bus IEEE RTS shows that the software developed is valid.