Temperature Effect on Dielectric Characteristics of Large Rotating Machines Insulation

Dielectric characteristics of insulation system of large rotating machines can be affected by operational and environmental conditions. Temperature, humidity and contamination affect dielectric parameters such as insulation resistance, polarization index and dissipation factor in certain degrees. In order to investigate temperature effect on characteristics of different insulation materials, time and frequency domain dielectric spectroscopy were conducted on five pieces of different bars and polarization and depolarization currents and dissipation factor were studied at different temperatures. Also temperature effect on insulation resistance of the samples is studied and accuracy of different temperature correction coefficients is investigated.