Noise Suppression Method for Pulsed Eddy Current Measurement of Substation Grounding Grids

The grounding grid of a substation serves as the primary discharge path for fault currents and is a critical component in ensuring the safe and stable operation of power systems. in recent years, the pulsed eddy current (PEC)method has gained attention as a research hotspot for grounding grid detection due to its non-destructive and efficient characteristics. However, during practical measurements, the signal is often severely affected by the complex electromagnetic environment of substations, and the presence of noise significantly increases the difficulty of data analysis. To address electromagnetic interference, this paper proposes a combined denoising approach targeting both power-frequency and random noise in substation grounding grid detection. First, the periodic nature of powerfrequency noise is utilized, and a bipolar cancellation technique is applied for effective suppression. Then, the Minimum Noise Fraction (MNF) algorithm is introduced to identify and reconstruct noise components in the signal, enabling initial suppression of random noise. Finally, denoising experiments are conducted using simulated noise and compared with several representative noise suppression algorithms from recent literature. The results demonstrate that the proposed method offers significant improvements in the quality of PEC data.