The micro-water content in transformer oil is an important factor to measure whether the transformer can operate stably for a long time. Based on multi-frequency ultrasonic detection combined with artificial neural network algorithm, a method for predicting micro-water content in transformer oil was proposed in this study. Firstly, the micro-water content in 210 groups of oils was determined by Carl Fischer titration. Secondly, 210 groups of oil samples were detected by multi-frequency ultrasound to analyze the relationship between micro-water content in oil samples and amplitude and phase signals in multi-frequency ultrasonic data. Finally, the original 242-dimensional multi-frequency ultrasonic data was reduced to 23-dimensional by PCA. Two prediction models for micro-water content in transformer oil based on PCA-GA-BPNN and PCA-PSO-GRNN were established by combining with BPNN and GRNN artificial neural networks as well as GA and PSO optimization algorithms. The prediction results were compared with the actual results. The results show that the forecast accuracy of both models is higher than 90%, which indicates that the method proposed in this study can effectively detect the moisture content in transformer oil.
| 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 |