Data-Driven Time-Frequency-Domain Equivalent Modeling of Wind Farms for Wideband Oscillations Analysis

Integration of wind farms into the power system could potentially lead to wideband oscillations (WBOs), threatening the stability of power system. Due to the high dimensionality of large-scale wind farms, the equivalent model should be constructed to facilitate the analysis of WBOs. This article proposes a data-driven time-frequency-domain equivalent modeling method of wind farms. The equivalent model of the wind farm is represented by a three-phase controlled current source which consists of steady-state components and small-signal components. It is demonstrated that the two components are related to varying operating conditions. Hence, parameter identification and numerical approximation are adopted to obtain the expressions of the two components. Besides, it is found that the dynamic characteristics of phase-locked loop (PLL) used for equivalence will inevitably introduce unignorable error to the equivalent model. Therefore, a compensation method is further proposed to guarantee the equivalent accuracy in both time and frequency domain. The proposed equivalent model can be constructed without knowing the structure or parameters of the wind farm, and is adaptable to varying operating conditions. Simulation results have verified its accuracy in both time and frequency domain.