Study on Electromechanical Distance of Electrical Power System

The propagation characteristics of electromechanical disturbance are studied by utilizing the concept of electromechanical distance (EMD), which can be used to divide a large-scale power system into a studying one and external ones, or divide the external system into several coherent subsystems. It is a necessary premise-step for dynamic equivalence. In this paper, first, a novel composite EMD is defined, and its physical meaning and computation method are also presented. Through the New England 10-machine 39-bus test system, the composite EMDs between the corresponding generator buses are computed by PSS/E modeling approach and the definition is presented in this paper. The results show their agreement when the generator inertia is relatively closed to that of other generators. However, the computation precision still needs further improvement if the generator inertia is rather far from others.