In order to realize the accurate assessment of the ageing state of transformer insulating paper, an ageing state assessing method of insulating paper based on combined assignment and improved TOPSIS was proposed. Firstly, in order to overcome the shortcomings of single feature quantity evaluation, polymerization degree, tensile strength, elongation at break, breakdown voltage, and dielectric loss factor were selected as ageing feature quantities to establish an evaluation system for the ageing state of insulating paper. Secondly, the combined weight value of feature quantities was calculated using the combined assignment model. Finally, an improved TOPSIS model was proposed to construct the Euclidean-gray correlation distance measure. The closeness degree was calculated using the improved TOPSIS model, and the closeness degree interval was set to grade and evaluate the ageing states of insulating paper. The results show that the ageing state assessing method of insulating paper based on combined assignment and improved TOPSIS not only considers the subjective experience weight of experts, but also uses the inherent characteristics of feature quantity data for weight correction, making the weight more scientific and reasonable. At the same time, it compensates for the distance criterion deficiency of the traditional TOPSIS model, making the calculated closeness degree more reasonable. Through the electricity-heat-force combined ageing test, the evaluation method has been verified to determine the ageing states of insulating paper accurately and effectively, and the grading evaluation of ageing states can be achieved by setting a closeness degree interval.
| 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 |