To address the issue of degradation in modal parameter identification accuracy caused by mode aliasing and noise contamination in power system disturbance recordings
a power oscillation modal parameter identification method based on enhanced variational mode decomposition (VMD) and Bayesian inference is proposed. First
a sparsity constraint is introduced into VMD
and a genetic algorithm is employed to optimize the number of modes and the penalty parameter
thereby improving the separation performance of oscillatory components. Then
a Bayesian inference model based on Markov chain Monte Carlo sampling is established. Moreover
the time-domain oscillation model is taken as the likelihood function
the posterior distributions of amplitude
frequency
damping factor
and phase are estimated
and the corresponding confidence intervals are obtained. Simulation cases and measured disturbance recordings from the Hunan power grid show that the proposed method can still be adopted to identify modal parameters accurately when the signal-to-noise ratio is no lower than 10 dB
while exhibiting good noise robustness and uncertainty quantification capability. The proposed method can provide supports for oscillation mechanism analysis and dynamic stability assessment in power systems.