A Noise Interference Suppression Method With Optimized Frequency Adjustment for Impedance Measurement

Impedance measurement based on small signal injections is an effective method to obtain impedance/admittance characteristic curves of the renewable power generation equipment (RPGE), which is essential to stability analysis. The safe operation of the power grid requires a limited duration of perturbation injection. To accelerate measurement process, adaptively adjusted frequency intervals can be utilized to facilitate the measurement points distribution and reduce the number of perturbation injections. However, the noise interference will degrade the obtained impedance results and derive unreasonable frequency distribution. To address this issue, this article proposes a noise interference suppression method with optimized frequency adjustment to enhance impedance measurement accuracy and efficiency. First, the noise characteristic is analyzed and modeled in the fitting algorithm based on Gaussian process regression (GPR) to obtain accurate impedance results. Second, the reflected curve tendency and error characteristics will be utilized to optimize the frequency distribution. Finally, the experiments based on control-hardware-in-loop (CHIL) are conducted to verify the effectiveness of the proposed method.