Influences Of Water Droplets On Corona Discharge Characteristics Of Transmission Line

Conductor corona,which will result intremendous negative impacts,is one of thosemajor factorsthat should be taken into consideration during the design and operationprocedure of transmission lines.So far, extensive studies have been conducted onatmospheric parameters and electromagnetic environment changescaused by conductorcorona. However, no research has focused on improving the corona of transmissionlines in rainy weather, also the deformation and the process of water in the electricfield is not clear. Because of the low surface energy of hydrophobic coatings that canreduce the number of the water droplets attached on the coated material surface, amethod to improve transmission line corona in rainy weather by using varioushydrophobic coatings on the wire is proposed for the first time in this study. The resultsare expected to improve the corona of transmission lines in rainy weather and thedischarge mechanism of water, so it is of important academic significance andengineering practical worthiness.AC corona test has been carried out in this article which is aimed to figure out thecorona characteristics of the coated conductor with water drops adhered to its surfaceinside a small corona cage. The deformation and the process of water in the electricfield is attained. The force vibration mechanism of water is analyzed. The electric fielddistribution of coated conductor attached with water is calculated. The followingconclusions are found:â‘ Because of the roll angle of superhydrophobic coating was extremely smalland the surface energy was extremely low, no droplet on the lower surface of theconductor covered with superhydrophobic coating was observed. The coronadevelopment of drying wire and the superhydrophobic coating conductor with watersis similar; it can be divided into two stages: corona-free zone and conductor coronazone. Howerver The corona development of drying wire and the superhydrophobiccoating conductor with waters is different. a) There are few waters attached on itssurface, it can be divided into four stages: corona-free zone, transient water dropletcorona zone, steady water droplet corona zone and conductor corona zone. b) it can bedivided into three stages: corona-free zone, transient water droplet corona zone andconductor corona zone when the conductor are full of waters.â‘¡Water droplets will vibrate at twice the frequency of AC electric field. In addition, during the vibration process, different position of water droplet leads todifferent distortion of space electric field, which will result in intermittentcoronadischarge. According to the burst types of the water droplets, the breakup voltage andthe minimum micro-drops jetting voltage are used to represent the characteristicparameters of the stability of the drops in the electric fieldâ‘¢According to the intensity of corona and time, the stable corona inceptionvoltages of conductor under different circumstances are defined.â‘£To certain extent, the PRTV coatings can reduce the breakup voltage andincrease the minimum micro-drops jetting voltage. Both of the PRTV coatings and thesuperhydrophobic coatings can improve the corona inception voltage of the conductorin the rain. The corona inception voltage can be improved from approximately8.9%~17.4%by PRTV coatings. The improvement is11.0%to24.6%withsuperhydrophobic coatings.