In order to study the ablation mechanism of buffer layer of corrugation aluminum (Al) sheath high voltage cross-linked polyethylene (XLPE), firstly, we analyzed a ablation failure of 110 kV XLPE insulated cable, and proposed that the concentrated radial current was the cause of ablation failure. Secondly, a simulation model of the faulty cable was established. The current density and its distribution of the contact part of buffer layer and corrugated Al sheath were simulated, and the simulation results were proved by model experiment and calculation. It was found that the size and distribution of radial current were affected by the embedded depth of Al sheath in the buffer layer and the volume resistivity of the buffer layer. Finally, simulation experiments were designed to prove that the radial current concentrated was one of the causes of buffer layer ablation, and the experimental conditions of the simulated ablation experiment were controlled in the thermostat. The surface morphology of the experimental sample and the ablated Al sheath were compared by optical microscope. The results show that the ablation process in the ablation experiment is the same as that in the actual faulty cable, and with the increase of the current density in buffer layer, the ablation start time decreases. This paper reveals the physical mechanism of radial current concentration in the ablation fault of corrugated Al sheath, which provides guideline for relevant fault diagnosis and protection.
| 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 |