Apparatus and method for out-of-step protection using the analysis of trajectories of electrical measurements in state plane

摘要

Various embodiments are described herein for a device and method for predicting an out-of-step or transient instability condition in a power system due to a disturbance, such as a fault, where the power system comprises a power generator. The method comprises determining values for a state plane trajectory for the power generator during the disturbance based on using an internal voltage angle of the power generator or an equivalent power generator and a during fault rotor speed of the power generator or equivalent power generator as state variables, determining time scale values; determining values for a critical state plane trajectory for the power generator after clearing the fault, determining values for a state plane trajectory for the power generator after clearing the fault, determining a critical clearing angle and a critical clearing time, and predicting that the power generator will be stable or unstable by comparing the time to clear the fault with the critical clearing time.