Distributed Electromechanical Oscillation Mode Online Estimation

Abstract

For the existence of low frequency oscillation phenomena in the interconnection power systems, a new style of distributed algorithm for detecting the low frequency oscillation modes was proposed to avoid the disadvantages of previous methods that require large amount of concentrated computation and communication. The whole structure of oscillation detection contains two levels, namely the substation level and control center level. In the substation level, damped sinusoid model based on atomic decomposition is employed to represent atomic library. Using the power angle trajectory, the modal parameters were identified from the atomic library by atomic decomposition method and atomic decomposition energy entropy was calculated during the identification process. In the control center level, the oscillation detection result of the substations are uploaded and combined to generate overall oscillation frequency and damping ratio by a weighted linear function. The results of a simulation case show that this algorithm can quickly detect the oscillation mode and the simulation results are identical to that of the normal form theory, and the accuracy and effectiveness of the proposed method were validated.