Application Of Modified Titanium Dioxide Photocatalytic Coating On DC Conductor Surface Antifouling

Due to extremely unbalanced geographical distribution of electric load center and electric power resources in our country,transmission technology of ultra-high voltage DC has achieved rapid development in recent years,and many uHVDC projects have been built and become operational.However,during the operation of the transmission line,due to the existence of dust or haze and other weather conditions,atmospheric particles are easy to accumulate and adsorb to the surface of the wire under the action of the electric field around the wire,which seriously worsens the surface state of the wire,increases its roughness,and eventually leads to the decrease of corona voltage.Therefore,it is of great significance to effectively remove particles on the surface of contaminated conductors to reduce the roughness of the surface,and to extend the operating life of HVDC lines.In this paper,in order to realize self-cleaning of surface particles under natural light,TiO2 nanomaterials were modified to act as photocatalytic coating material for wires,and the improvement effect of coated wires on surface state and corona characteristics of polluted wires was studied through experiments.The main research contents include:Firstly,non-doped and titanium dioxide nano-powders with different proportions of nitrogen doping were prepared.The phase structure,surface composition,light absorption and photocatalytic properties of each sample were characterized,and the doping proportions with the best catalytic activity under UV and visible light were evaluated.The supercell models of undoped,N-substituted doped and N-gap doped were constructed.The electronic structures and optical properties of the three structures were calculated based on first principles,and the microscopic mechanism of N-doped modification extending the photoresponse range of anatase titanium dioxide was revealed.Secondly,in order to facilitate the characterization of roughness of a large number of wire samples in subsequent experiments,a method was proposed to process wire surface images taken by high-definition cameras,obtain the gray matrix and gray coexistence matrix of the gray image and the corresponding characteristic parameters to evaluate the state of wire surface,and the reliability of the method was verified.Finally,the improvement effect of the photocatalytic coated wire on the surface state and halo characteristics of the fouling DC wire was experimentally studied,and the influence rule of different catalytic duration and different catalytic electric field on the photocatalytic process was obtained.The difference of the performance of the unmodified titanium dioxide coating and the modified titanium dioxide coating under ultraviolet and visible light conditions was explored.In addition,the effect of the photohydrophilicity of the modified titanium dioxide coating on the water droplet morphology and corona initiation voltage of the wire surface was investigated.