Research On Low-frequency Oscillation On Resonance Mechanism In Multi-machine Power System

Low frequency oscillation is an important problem which affects the security and stabilization of power system. This dissertation concentrates on the research of power system low frequency oscillations of resonance mechanism.The effects of system's related factors on oscillations,resonant oscillations in multi-machine power systems and it's influence factors,resonant oscillations of multi-modes in close modes power systems are comprehensively studied in this paper.In accordance with the resonance mechanism of low frequency oscillations,the characters of oscillations and the effects of system's influential factors on oscillations are analysed in this paper.Using eigen analysis method,the mechanism of the low-frequency oscillation on resonance mechanism in multi-machine power system is expounded.Four-machine two-area system were taken as the research object.The simulation analysed the situation of low-frequency oscillation on resonance mechanism of each oscillation mode under the influence of disturbance source.Analysed the impact of participation fators of machine and damp of mode on the oscillation.Representative local and regional modes of multi-machine model are analyzed and compared.In accordance with the feature of close oscillation modes in power system,models of multi-machine power system were established.Studied the low-frequcecy oscillation on resonance mechanism of multi modes while frequency of multiple oscillation modes are close.The active power disturbance in related machine of two close modes caused resonant oscillation of the two modes.Due to the connection and effection of related machine of two close modes,when one of the two modes occurred resonant oscillation,another mode can also occured obvious resonant oscilation phenomenon.The impact of related machine of multi-modes on each oscillation mode which have directly relationship with participation of the machine to each oscillation mode.