Basin insulator is an important part of gas insulated closed combination switchgear (GIS) device, and its quality has an important impact on the construction and operation of power grid. In this paper, the failure causes of basin insulators were described, and the existing detection methods were compared in common cracking locations. According to the material characteristics of basin-type insulators and field test conditions, the probe frequency, K value, and chip size were calculated theoretically. An ultrasonic water immersion focusing oblique probe device was developed, a method of detecting cracks near the bolt holes of basin insulator by using the low-frequency dual-probe ultrasonic detection technology was proposed, and the test results were verified by laboratory penetration and ray detection. The results show that the ultrasonic refraction transverse wave with high signal-noise ratio can be generated in the basin insulator by using dual probes with 2 MHz 18×18 mm of model size and 24.8°-35.4° of angle (αL) between the axis of the wafer emission acoustic beam and the normal line of workpiece interface. It is feasible to use special low frequency double probe ultrasonic detection technology to detect the defects of GIS basin insulators.
| 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 |