Abstract: Given the current operating condition of a power-generating system (obtained from real-time data), the near-term (e.g., after 25 min.) load demand at each bus (obtained from short-term load forecast) and the generation dispatch (based on economic dispatch), a load margin measure (MW and/or MVAR) is determined in order to assess the system's ability to withstand the forecasted load and generation variations. The invention has a method to predict near-term (e.g., after 25 min.) system voltage profiles. The proposed look-ahead measure and/or the system voltage profiles are then applied to contingency selections for the near-term power system, in terms of load margins to collapse and bus voltage magnitudes. The proposed load margin measure and the voltage profiles are based on the power flow technique and the saddle-node bifurcation theory.

Abstract: A method for on-line dynamic contingency screening of electric power systems employs a sequence of contingency classifiers which are based on a method for finding the controlling unstable equilibrium point of the power system known as the boundary of stability region based controlling unstable equilibrium point method (BCU method). Dynamic security assessment of the power system is accomplished by evaluating the power system's response to a plurality of postulated disturbances known as contingencies. The BCU classifiers determine which of these contingencies are definitely stable, and require no further analysis. Other contingencies which are either classified as being unstable or undecided are then applied to a time-domain simulation program to determine if they are in fact unstable, and therefor warrant further action.