A Search for the Power System Stability Limit at a Specified Controlled Cutset by Applying a Flow Model

Currently, static aperiodic stability in the power system within operational dispatch control is maintained by monitoring active power flows through controlled cutsets. According to the existing regulatory and technical documentation, the search for the maximum flow based on the static aperiodic stability criterion must be carried out by aggravating the operation mode in a specified loading direction. For a large power system, there are many different operation mode aggravation trajectories, and the corresponding maximum flows through the cutset can vary significantly. To ensure static stability, it is necessary to consider at least three different aggravation trajectories and select the one that results in the lowest maximum active power flow through the cutset. Thus, the search for the maximum flow is an empirical search problem. The article proposes a method for determining the maximum flow in terms of static aperiodic stability through a controlled cutset using a nonlinear programming method without the need to enumerate different loading trajectories. A flow model is used as the equations describing the steady-state mode to improve the numerical performance of the method. Techniques using which the numerical performance of the proposed method can be improved are considered. Numerical experiments demonstrating the capacities of the proposed method are carried out.