Fast prediction of the power-swing curve across transmission lines during wide area disturbances

This paper presents a fast prediction algorithm for the power-swing angle curve across a transmission line in a multi-machine power system following a major system disturbance. The methodology views the multi-machine power system from the transmission line perspective and exploits the principles of equivalent machines at each end of the transmission line as developed for the extended equal area criteria. The algorithm expands the swing center voltage concept to obtain a closed-form relation for the power-angle difference between the equivalent machines at each end of the transmission line. A curve fitting process is invoked to find the swing-curve from pairs of the power-angle estimates and the line sample power measurements. The results are compared with the time domain integral solution of the equivalent system swing equation using the center of inertia angle of the equivalent two-machine system in the post-disturbance period.