| Running UHV transmission lines will inevitably bumped in the constructionprocess leading to scratch the wire or wire itself exists prominent metal, forminglocal corona discharge point sources. At present, in order to reduce the corona loss,widely used increasing the wire diameter or the number of split or method ofincreasing tower height. Although these methods can achieve the effect of reducingthe corona loss, but the investment is large, and to large-scale replacement of wiresor raise the tower height is unrealistic, there are some limitations in practice.Therefore, for the transmission line conductor made late repair inevitably a kind ofeffective shortcut to reduce the corona loss. This paper discusses use RTV coatingto improve the transmission line corona discharge phenomenon.Studying transmission line corona loss by corona cage is a cost-effectivemethod. Corona cage can simulate conductor surface field strength conditions oftransmission line. Corona cage is widely used in conductor corona characteristicsstudy. Paper based on the laboratory small corona cage, use ultraviolet imagingtechnique to monitor corona discharge of smooth conductor and LGJ400/50underscratches and protrusion surface state, and the influence of discharge after paintingcoating. Use corona loss measurement system measuring resistance current andcorona loss, using the method of tangent play the corona onset voltage, analysis theeffect of coating on the corona loss.The result shows that corona onset voltage of wire under scratch is105kv,after painting coating the voltage become120kv, increased14.29%. When thevoltage is130kv, corona loss decreased55.0%; Under the condition of the surfacecoated carbon particles, after painting coating the corona onset voltage from96kvto109kv, increased13.54%, when the voltage is130kv, corona loss dropped24.6%. The existence of the scratches and protrusions, make the conductor coronainception voltage dropped, let the wire can reach corona onset voltage under lowervoltage, paint cover changed the surface condition of the wire, improved the coronaonset voltage, and under the same voltage, the conductor surface dischargephenomenon blunts, the corona loss is reduced. |
