| Popis: |
Outdoor insulators, one of the vital electrical equipment related to the operating security and stability of power system, play an essential role in electrical insulation and mechanical support. Therefore, it's very necessary to study the faults of outdoor insulators, especially contamination flashover, which regularly happens due to the contaminated particles depositing on the insulator surface. Furthermore, the characteristics of contamination deposition on outdoor insulators are demanded to prevent the contamination flashover. In this paper, Fluent software was used to establish the fluid mechanic model of outdoor insulator with contaminated solid particles. In the model, the air around the insulator was set as a continuous phase for transient turbulent fluid simulation calculation, and the contamination particles were set as discrete phase for coupled steady state calculation with air to obtain the collision rate. The characteristics of collision rate in relation to wind speed, particle size, particle concentration and the gravity was analyzed through studying the distribution of air flow around the insulator. The obtained results reveal that the movement trajectory of the particles that attached to the insulator surface mostly depends on the flow of air, especially the gravity and the wind speed. The maximum value of static pressure increases as the wind speed increases which appears near the edge of the windward side of the two large sheds. The minimum value appears at both ends of the insulator and decreases as the wind speed increases. The airflow velocity of the leeward side of insulator is small. Furthermore, the larger the particle size is, the more obvious the effect of gravity sedimentation is, the greater the collision rate is. When the wind speed is higher, the collision rate will increase firstly and then decrease. When the concentration of the contamination particle increases, the deposition of contamination particles gets more seriously, but the collision rate is generally unchanged. |
