This paper investigated the generation laws of characteristics gases at the cross-linked polyethylene-silicone rubber insulation interface of cable accessories under different types of discharge faults, and proposed gas diagnostic criteria for discharge fault types at the cable accessory interface based on this. Firstly, a gas generation experimental platform for insulation interface discharge of cable accessories was established, different types of discharge faults were distinguished by the high-frequency current transformer method, and the characteristics of the escaping gases from insulation interface discharge faults were analyzed by gas chromatography. Then, a real-type discharge fault gas generation platform of cable accessory was built to experimentally verify the generation laws of characteristic gases under interface discharge faults. Finally, the diagnostic criteria for discharge faults in cable accessories were proposed based on characteristic gas formation laws. The results show that the insulation interface mainly generates H2, CO2, CO, CH4, and C2H6 under low-energy discharges (partial discharges), while additionally produces C2H4 and C2H2 under high-energy discharges (arc discharges). Based on this, a comprehensive gas diagnostic criteria is proposed: when the concentration ratio of CO to CO2 is between 0.10 and 0.69, it is considered as low-energy discharge; when it is greater than 0.70, it is considered as high-energy discharge. Only the first five gases are present in the gas composition, it is considered as low-energy discharge; while both C2H4 and C2H2 are detected, it is considered as high-energy discharge. Quantitative indicators show that the proportion of unsaturated hydrocarbons in high-energy discharges ranges from 0.07 to 0.16, and the concentration ratio of unsaturated hydrocarbons to H2 ranges from 0.08 to 0.30.
| 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 |