Epoxy resin impregnated crepe paper (ERICP) insulating materials are widely used in power equipment insulation, and moisture is an important reason affecting their insulation state. In this paper, the frequency domain spectroscopy (FDS) technology was used for insulation condition evaluation. Firstly, ERICP samples with different moisture content were prepared and carried out FDS tests. Then, according to the FDS spectrum curves, the variation law of FDS characteristic parameters with moisture content was analyzed. Finally, the dielectric modulus spectrum and modulus factor were introduced, and the insulation condition evaluation method of ERICP was proposed. The results show that the change of moisture content affects the overall change law of FDS curves. The dielectric modulus can effectively suppress the influence of DC conductivity to characterize the internal relaxation process. The dielectric modulus spectrum of ERICP samples has obvious relaxation peak in the low-frequency range, and the characteristic frequency of relaxation peak increases with the increase of moisture content. The integral area of the imaginary part of dielectric modulus can be used as a characteristic parameter to characterize the insulation condition of ERICP. The relationship between the modulus factor and moisture content has 0.997 5 of goodness of fit with the exponential function.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |