Insulation Aging Assessment of Low-Voltage Control Cables for Railway Vehicles Based on Dielectric Spectroscopy

To investigate aging characteristics of insulation materials used in low-voltage control cables for railway vehicles, insulation performance was evaluated through accelerated thermal aging tests combined with dielectric spectroscopy analysis. Results revealed the relationship between dissipation factor of insulating materials and frequency, especially the high sensitivity to aging in the low-frequency range (0.002~1 Hz). During aging process, the increase of dissipation factor indicated a decline in insulation performance. Additionally, a correlation model between dissipation factor and elongation at break was established, verifying the reliability of using dissipation factor to assess insulation aging. Dielectric spectroscopy test is a non-destructive inspection, which can provide new methods and technical support for the safe operation of cables, and it has broad application prospects.