339 / 2022-03-15 15:53:35

Study on Moisture Distribution Characteristics of Oil-paper Insulation Based on Frequency Domain Spectroscopy

Moisture distribution characteristics,Oil-paper bushing,Frequency domain spectroscopy,Uneven damp

Purpose/Aim

Oil-paper bushing has been widely used in power system because of its good electrical and mechanical properties. Moisture is the most important factor affecting the safe and stable operation of bushing. Due to the influence of temperature and gravity, the moisture distribution in bushing is often uneven. In order to evaluate the moisture content of bushing more accurately by frequency domain spectroscopy (FDS), the variation characteristics of FDS curves of oil-paper insulation samples under uneven damp were studied.

Experimental/Modeling methods

Based on the principle of dilute material transfer, the moisture distribution model of bushing was constructed, and the moisture distribution curves under different diffusion time was calculated, which laid a foundation for studying the dielectric spectrum characteristics of uneven damp samples. On this basis, the transverse and longitudinal damp models of three element laminates were established, and the variation laws of frequency domain dielectric spectrum curves under different equivalent moisture content and different damp modes were studied.

Results/discussion

The results show that when the unevenness of the oil-paper insulation combination model increases, the overall characteristics of the tanδ-f curves show a trend of moving to high frequency and high amplitude. The overall characteristics of the curves are quite different from the dielectric characteristics of the model with low internal moisture content, and are in good agreement with the dielectric characteristics of the model with high internal moisture content.

Conclusions

In this paper, the dielectric response characteristics of oil-paper insulation with uneven damp under different operating conditions are studied by COMSOL simulation and experiment, and the reasons for the change of the curves are analyzed, which provides a theoretical basis for early warning and fault diagnosis of oil-paper insulation equipment.