Research on forced oscillations disturbance source locating through an energy approach

Abstract

Low-frequency oscillations (LFOs) are inherent phenomena of modern interconnected electrical power systems, essentially caused by the continuous exchange of momentum among rotating masses. It is widely recognized that LFOs can be induced by both the occurrence of multiple disturbances and the existence of periodic disturbance sources. LFOs can be classified into negative damped oscillations and forced power oscillations. The former can be suppressed by standard controllers (e.g., power system stabilizers). The latter cannot be eliminated until the disturbance source is removed or isolated. Thus, locating the forced disturbance source promptly and accurately is crucial. In this paper, a traditional energy function, simplified and improved, with a new decomposition way to show the direction of energy flow is proposed. Energy associated with the LFO is decomposed into oscillating component and quasi-steady component at the aim of analyzing the inducing multiple disturbances. The branch energy is hence decomposed into periodic and aperiodic components. By identifying the direction along which the aperiodic component is propagated and dissipated, the periodic forced disturbance source could be located rapidly and accurately. The proposed energy decomposition method provides a novel idea to judge the direction along which the dissipated energy flows. The effectiveness and feasibility of the proposed method were verified by simulation results obtained on an actual large-scale interconnected power grid in China. Copyright © 2015 John Wiley & Sons, Ltd.