The characteristic ellipsoid methodology and its application in power systems

The characteristic ellipsoid (CELL) method to monitor dynamic behaviors of a power system is proposed. Multidimensional minimum-volume-enclosing characteristic ellipsoids are built using synchronized phasor measurements. System dynamic behaviors are identified by tracking the change rate of the CELL's characteristic indices. Decision tree techniques are used to link the CELL's characteristic indices and the system's dynamic behaviors and to determine types, locations and related information about the dynamic behaviors. The knowledge base of representative transient events is created by offline simulations based on the full Western Electric Coordinating Council (WECC) model. Two case studies demonstrate that the CELL method combined with the decision trees can detect transient events and their features with good accuracy.