Electrical Conductive Theory And Lubrication Technology Of Conductive Grease In Electric Transmission/Transformation Equipment

Electric contact exists in modern power system, automatic control system and information transmission system, and has been widely used in electro mechanical equipment, power machinery equipment and electric transmission/transformation equipment. The overheating of electric contact area often results in equipment failure, and the protection and lubrication of electric contact area is an effective solution. Although traditional grease has excellent tribological properties, it still has some disadvantages in lubrication of electric transmission/transformation equipment or mechanical equipment which are mainly based on electric contact. Working at current-carrying condition, conductive grease is applied to the electric transmission/transformation equipment, and is responsible for some important tasks, such as electric transmission and electric signal transferring at the state of fretting contact. Therefore, conductive grease is required to possess good lubricity and electric conductive capacity to ensure the power machinery equipment and electric transmission/transformation equipment operating reliability and stability. This thesis studies on conductive grease, which is applied to electric transmission/transformation equipment, and the main research contents and results are listed as follows:1. By means of coordination effect between three kinds of alkalis lithium salts (including LiBF4, LiPFe and LiNTf2)and ethers (PAG, PEG, G2 or G4), ionic liquids (ILs) were respectively "in situ" synthesied in base grease to prepare ILs-conductive greases. The influence of ILs on the conductive capacity and tribological properties of conductive greases were investigated. The experimental results reveal that conductive capacity enhances gradually with the ILs concentration increasing; the highest increasing in conductive greases conductivity is seven orders of magnitude. Meanwhile, this type of ILs-conducitve greases exhibit excellent friction-reducing and anti-wear performance.2. CNTs-conductive greases were prepared using SWCNTs, MWCNTs and CMWCNTs as additives, respectively. The experimental results indicate that CNTs can greatly improve the conductivity of conductive grease; at the concentration of 1.0%, the conductivity increases four orders of magnitude and the conductive greases exhibit the good friction-reducing and anti-wear capacity. Additionally, SWCNTs performs the best among the CNTs.3. ATO-conductive greases were prepared using nanometer ATO as additive. The experimental results show that ATO can improve the conductive capacity of conductive grease by reducing contact resistance; at the concentration of 1.0%, the contact resistance can be reduced by nearly 1/3. The friction-wear experimental results show that ATO possesses better lubricity than Cu and Ag particles at certain condition.4. Insulation greases were prepared using nanometer SiO2 and nanometer TiO2 as insulation additives, respectively. The insulation greases possess good insulation property; at the concentration of 0.1%, the conductivity of insulation greases reduce by nearly 30%, and the insulation greases also possess good friction-reducing and anti-wear properties at this concentration. Additionally, additives possess good properties can further improve the lubricity of insulation greases.