Degraded Composite Insulator Detection Method based on Spatial Electric Field Measurement

Composite insulator degradation poses severe risks to power grid stability, rendering live detection of internal defects critically significant. The electric field detection method, as a non-contact solution, suffers from lack of field measurement data and unclear criteria for electric field-based degradation identification. To address this challenge, field samples of composite insulators with decayed and carbonized core rods are selected, and electric field distribution tests are conducted to capture the fundamental distortion characteristics induced by degradation. Subsequently, artificial simulation experiments are performed to investigate local electric field distortion characteristics under varying degradation severities, positions, detection distances and different installment configurations. Based on these findings, a four-array local electric field detection method and criteria are proposed and validated through testing on field-degraded insulators. The results indicate that the four-array detection method effectively identifies carbonization and decay defects in composite insulator core rods, with characteristic criteria being that the ratio of maximum to minimum electric field amplitudes Q1satisfies 112satisfies 12