A Method to Suppress Electromechanical Oscillation Modes Based on Sensitivity of Electromechanical Loop Relevance Ratio

The electromechanical oscillation mode (abbr. EOM) is a low-frequency oscillation (abbr. LFO) mode strongly correlated to the mechanical transient of synchronous generator (abbr. SG) and has a great impact on shafting security of the synchronous generators and grid stability. By means of reducing the electromechanical loop relevance ratio ρ, the relevancy of EOM and SG can be decreased and the oscillation of SG can be restrained. On this basis, the model of the sensitivity of electromechanical loop relevance ratio to SG output was proposed, the sensitivity of ρ to the control parameter was expanded into the sensitivity of participation factors. Considering that the participation factor was composed by eigenvectors, the unique solution of eigenvector sensitivity was obtained by replenishing the amplitude and phase constraint of the latter. Considering the affection of SG output on nodal voltage and eigenvalue, however, such an affection was not shown in the state matrix, the inverse matrix of Jacobian matrix of power flow solution was led in and the sensitivity of eigenvalue and eigenvector to SG output was established, and then the analytic expression of ρ to the sensitivity of active and reactive output of the SG was put forward. Finally, by means of analyzing computing examples, the accuracy of the sensitivity model of EOM and its eigenvectors, that of the participation factor and that of ρ to the output of the SG were verified. Thus, the control effect of restraining EOM by regulating active and reactive output of the SG is validated.