Study Of Corona Phenomena And Its Influence Factor On DC Conductor In A Corona Cage

When the project of the first±800kV UHV in China has been constructed, theelectromagnetic environment has been one of the key factors to be considered in designand operation of UHV transmission lines. This paper is based on the test model of a littlecorona cage and three kind of conducting wire with different radius,utilized the methodof testing corona current and corona audible noise to observe the whole process ofcorona inception on DC conductor,then studied the influence of temperature andhumidity toward corona inception voltage on DC conductor. The results indicate that theprocess of corona inception on clean DC conductor under the effect of positive andnegative voltage is different; The corona inception voltage on clean DC conducting wireis rising with the rising of temperature, the influence of tempreature is mostly caused bythe mean free path of molecule in the air; the corona inception voltage on clean positiveDC conducting wire is rising with the rising of humidity in some sort,the coronainception voltage on clean negative DC conducting wire is rising at beginning thenreducing at end with the rising of humidity, we considered that the influence of humidityis mostly caused by the restaining effect that the strong negative water molecule or watermolecule group brings to electron collapse and its asymmetric attachment on the surfaceof electriferous wire.