Contamination Characteristics of Suspension Composite Insulators in Wind Tunnel under Energized Condition

摘要

In order to study the pollution characteristics of suspension composite insulators, the wind tunnel experiments of typical big-small sheds composite insulator were carried out with different wind speed under voltages of different polarities and levels. The results showed that the NSDD (non-soluble deposit density) of composite insulator increases with the increase of wind speed, contamination degree of leeward side of insulator is greater than that of windward side, contamination degree of top surface is greater than that of the bottom surface, and NSDD of small shed surface is slightly larger than that of big shed surface. Thus, positive and negative polarities of DC voltage have similar effect on increase of contamination on insulator surface while AC voltage has almost no effect on the contamination degree. In the DC energized condition, the contamination distribution along the string is also non-uniform. In order to explain uneven distribution phenomenon along the string, the multi-physics coupling software COMSOL is used to calculate the electric field around the insulator. Furthermore, basing on field charging theory, the value of electric field force on particles around insulator surface was calculated and the mechanism of uneven contamination distribution on insulator sting was then explained. The research method and results can provide not only reference to establishing natural contaminating model but also significant meaning for the external insulation design and selection.