Research On The Influence Of Water Drops And Ice To The Corona Characteristics Of AC Power Transmission Lines

Since transmission channel of the UHV and EHV have long-distance characteristicsin China，part of the lines inevitably cross the complex environment climate zones(rain、icing、contamination and so on)．Conductor surface status will have influence on thecorona characteristics of transmission lines，while the corona effect is one of the keyissues which should be considered in the design of UHV and EHV transmissionlines．Therefore，research on conductor corona loss under water drops and ice plays animportant role on high voltage transmission line design and construction．With the help of self-developed the laboratory corona cage and optical fiber digitalcorona loss measurement system，the corona loss curve of the wire under surface waterdrops and ice can be obtained．Two type conductors(smooth pipe and ACSR) are chosenas test wires and conductor surface water drops and ice test is done with configuringthree different conductivity of icing water．In order to study corona discharge inceptioncharacteristics of the conductor surface with water drops，change the number of drops onthe test wire surface；With the help of self-designed icing test platform，by varying thelength of the icicles，the influence law of different degrees icing on wire corona dischargeare analyzed．While，using the tangent method to gain the conductor corona onsetvoltage，then we analyze influence of drop and ice to corona onset voltages．In addition，in the application of finite element method and with the ANSYS electromagnetic analysissoftware， we establish a smooth icing conductor two-dimensional electric fieldmodel．Frustum-shaped and cylindrical icing models are selected to simulate icicles．Weanalyze influence of conductor surface icing to conductor surface field strength on thethickness，icicle length and bottom diameter of the icing model．Research results show that with the increased numbers of drops，the conductorsurface corona loss increases gradually，corona loss curve＂inflection point＂is leftshift，and the corona onset voltage reduces．With the increase of icicle length，conductorcorona loss increases significantly，correspondingly，conductor corona inception voltagedecrease；When icicle length increases to about18mm，the corona inception voltage andcorona loss remain almost unchanged．The conductivity of icing water has little impacton corona inception voltage of conductor surface with drops and ice in certain range．...