Research on Influence of Voltage and Moisture on Frequency Domain Spectroscopy of Epoxy Resin

Epoxy resin and Al
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/epoxy resin composite materials are widely used in electrical equipment insulation. In order to evaluate the effectiveness of frequency domain spectroscopy (FDS) for epoxy resin and alumina/epoxy resin composite insulation damp defects, in this paper, two kinds of insulation samples are prepared to study the influence of voltage and moisture on FDS curves of two insulation materials by using dielectric response test platform. The results show that the applied voltage has little effect on the high frequency range (1Hz-5kHz for pure epoxy resin , 20mHz-5kHz for Al
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/epoxy resin) of FDS curves, while the tanδ of low frequency band decreases with the increase of voltage. With the decrease of water content, the low frequency band of FDS curve decreases gradually, while the Al
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/epoxy resin curve decreases over the entire frequency band (1mHz-5kHz). Since moisture has the greatest influence on tanδ of the two insulations at 0.01 Hz, this frequency point can be used as the characteristic frequency for diagnosing damping defects of the two insulations.