A new method based on S-transform and time-frequency domain reflection (TFDR) was proposed to locate the local defect of power cable. The principle of traditional cable defect location method was analyzed firstly. The time-frequency distribution of the TFDR test waveform was obtained by S-transform, and the time-frequency cross-correlation function of time-frequency distribution was calculated. Then the location of cable local defect was estimated by the local peak of the time-frequency cross-correlation function curves. The results show that compared with the traditional TFDR methods, there is no cross-term interference problem in the time-frequency distribution for the proposed method, so the local peak of interference in the time-frequency cross-correlation function curve is eliminated, and the reliability of cable defect location results is high and the detection blind area of local defect is small. Finally, the simulation and measurement analysis were carried out on the 10 kV cross-linked polyethylene (XLPE) cable, and the results show that the proposed method can effectively locate the local defect of cable and the absolute error of defect location is small.
| 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 |