A Benchmark System for Verifying the Harmonic Amplification Mechanism of Wideband Oscillations

To verify the harmonic amplification mechanism of wideband oscillations, this paper constructs a benchmark system. Firstly, the theoretical framework of the harmonic amplification mechanism for wideband oscillations is elaborated. Subsequently, the structure and parameters of the benchmark system are presented. Based on the s-domain nodal admittance matrix method, the resonant characteristics of the benchmark system, including resonance frequency, damping ratio, and nodal voltage mode shape, are calculated. Using electromagnetic transient simulation, the time-domain waveforms of current, voltage, and power of the benchmark system under typical operating conditions are obtained, and harmonic decomposition of these waveforms is performed. By comparing and analyzing the harmonic components of current, voltage, and active power with the resonant characteristic quantities, the harmonic amplification mechanism of wideband oscillations is verified. The applicability of analyzing the harmonic amplification effect based on the positive-sequence network model is demonstrated. It is shown that the resonance frequency, damping ratio, nodal voltage mode shape, and resonant peak voltage are four key factors determining the harmonic amplification effect. Finally, the relationship between the frequency of the oscillatory power component and the frequency of the harmonic source is revealed.