Dynamic equivalents from on-line measurements

This paper presents the results of a feasibility study of a technique for identifying dynamic equivalents of portions of a power system from measurements made only within a restricted Study System without intentional perturbation of the system. The Maximum Likelihood technique is used to identify parameter values for a specified equivalent structure which is suitable for direct use in standard transient stability programs. The identifier was tested using measurements from simulations tuned to match field measurements. The field measurements, identification algorithm, and program test results are described. The expected benefit of this technique is in overcoming a major block in the development of an on-line technique for the evaluation of transient stability contingencies by power system operators.