New results on stability monitoring on the large electric power system

This paper summarizes an efficient two stage monitoring technique for power system stability which was developed in the course of a DOE sponsored project [9] at Washington University. The process utilizes an unusually effective technique [6] for identifying coherent dynamic clusters within a power system and the connections between the clusters and critical swings in the power system. In the first stage transient energy injected into the power system is compared with critical energies which can drive the cluster into separation. Failing this sufficiency test the condition then is evaluated by testing the initial states position directly with respect to the stability boundary. An efficient expansion which is easily derived on the computer is used. Only one scalar value needs to be computed for each candidate. Theoretical basis for this work was developed in [9] and is to be published soon in the AC Transactions [4]. New theoretical, computational results on identifying order N-1 equilibria is also given in this paper.