Research On Surface Discharge Characteristics Of Silicone Rubber/SiO₂ Nanocomposite

With the increase of transmission voltage and environmental deterioration,traditional ceramic and glass insulators are affected by many aspects,such as volume,weight,resistance to pollution and so on.These insulators have been unable to meet the basic requirement of the safe and reliable operation of power system.Silicone rubber?SiR?with the excellent hydrophobicity and migration property of hydrophobicity,has gradually replaced other organic materials and has been largely applied in the external insulation of the electric power system,achieving the considerable benefits.However,after a long period of operation,the insulating reliability of SiR is influenced by many factors,of which aging caused by surface arc discharges is one of the main influence factors.This study conducted the inclined-plane tracking and erosion test under ac voltage,analyzed the surface arc discharge from current characteristics,arc characteristics and external and internal erosion,and researched the effects of adding nano-SiO₂ particles to silicone rubber on arc discharge activities.The main contents and conclusions are as follows:1)When arc discharges occurred on the specimen,leakage currents were sampled by the data acquisition system and analyzed further.The study found that the currents were mainly composed of fundamental,third harmonic and fifth harmonic,and that the more intense the discharge was,the higher the current amplitude was.Through the calculation of cumulative charges at different frequency band,it was found that cumulative charges in the same time showed a decrease trend with the increase of nano-SiO₂ particles.2)The intense arc discharge would cause erosion on specimen surface and form the carbide channels,reducing the insulating property,and also lead to damage in the specimen,showing micro cracks,promoting the recovery of hydrophobicity.The addition of nano-SiO₂ particles into silicone rubber could reduce the surface erosion and inner damage caused by arc discharge.3)Generally,discharge would radiate visible light,which could be used to analyze the discharge position and strength.Energies generated by arcs were the main source of surface and inner erosion for the specimen,so the erosion degree could be researched by discharge energies.The tests found that with the increase of nano-SiO₂particles in silicone rubber,the discharge energies showed a decrease trend at the same period,causing less erosion to silicone rubber.Therefore,the addition of nano-SiO₂ particles can significantly enhance the resistance to arc ablation for silicone rubber.