Research on Insulator Defect detection by Laser Ultrasonic Numerical Simulation

With the rapid development of ultra-high-voltage power grids, the mechanical reliability of post insulators has become a critical factor in ensuring system security and stability. Addressing the prevalent issues of circumferential cracks at flange-porcelain interfaces and internal defects, this study proposes a laser ultrasound-based quantitative inversion modeling approach for defect detection. A thermoelastic numerical model was established using COMSOL Multiphysics 6.2 to simulate ultrasonic wave propagation in insulators with defects, elucidating the interaction mechanisms between defects and ultrasonic signals. For surface cracks, the propagation time models of RR and RS waves were employed to precisely invert crack locations and depths; for internal defects, a geometric model based on SS waves was derived to quantitatively calculate defect depths. Simulation results demonstrated significant quantitative correlations between the propagation times of RR, RS, and SS waves and the depths of cracks and defects, validating the reliability of the proposed method. This research provides theoretical and technical support for insulator defect detection, offering insights to optimize detection system design, enhance detection accuracy, and ensure the safe operation of power grids.