Effect of Humidity on the Properties of Frequency Domain Spectroscopy of Rotating Machines Epoxy/mica Insulation

To study the effect of humidity (M) on frequency domain spectroscopy (FDS) test of rotating machines epoxy/mica insulation, the stator bar was put in different humidity container and was tested with FDS. Cole-cole model was built to study the effect of humidity on FDS test of epoxy/mica insulation with the microscopic relaxation. The results show that with M increasing, epsilon' and epsilon '' of epoxy/mica insulation increase and move towards higher frequency in 10(-3)similar to 10(3)Hz, besides, interface polarization and dipole steering polarization are strengthened and the band interfacial polarization plays a leading role gradually widens. Interfacial polarization relaxation time constant tau(1) show a linear exponential relationship with M. It can eliminate the influence of humidity on FDS test of the epoxy/mica insulation with relationship between tau(1) with M in the process of data analysis, which can make it easier to diagnose the status of generator insulation with FDS technology.