Feasibility Research of Aging Status Assessment of Steam Turbine Generator Insulation by Frequency-Domain Dielectric Spectroscopy

To study the feasibility of applying frequency domain dielectric spectroscopy method to the diagnosis of generator insulation aging state. Dielectric spectrum of motor stator bar sample was measured using frequency domain dielectric spectroscopy method under different aging degree and different temperature. Then the relationship of dielectric loss factor and complex dielectric constant with aging state was researched. The influence of temperature on the frequency domain dielectric characteristic was also analyzed. Results show that dielectric spectrum at low frequencies are sensitive to the aging state of bar sample, which can assess the aging state. Temperature had a great influence on the measured results. Spectrum curves increase with the rising of temperature and moves to higher frequency. The influence of the temperature should be considered.