Real-time measured fault impedance and EMS based transient stability on-line forecasting

An on-line forecasting algorithm for transient stability of power systems, based on real-time measured fault impedance and EMS, is put forward in this paper. The proposed algorithm combines PMU measurements and EMS models organically. Models, initial states and fault information are three basic aspects of time-domain simulation for transient stability. Once a fault occurs, models and initial states are obtained from EMS, while fault information is calculated with the help of PMU measurements. Then time-domain simulation with a super-real-time speed is carried out, to forecast transient stability of the system. Forecasting algorithms are given, and several main factors affecting the accuracy are studied. A binary search method is present to decrease errors caused by different sampling types. The proposed algorithm is tested on IEEE 39-Bus system. Simulation results demonstrate its effectiveness and feasibility.