Electrification current and voltage on a cylindrical object in the presence of an ion flow field in an air stream

The paper is concerned with the assessment of the electrical environment in the vicinity of HVDC transmission facilities; the ion flow electrification phenomenon has been recognised as the subject of extensive research. The determination of current and electric field at ground level under the facilities and the estimation of electrification quantities on objects placed in an ion flow field is the basis of the design of conductor geometries. It has been found from measurements of current and field using the model-scale and full-scale transmission lines, that the current distribution at ground level is strongly influenced by wind, although the effect of wind on electrification quantities on an object placed in the ion-flow field is not understood in detail. In the present study, the electrification current and voltage on a cylindrical object placed in an air stream containing unipolar ions are estimated from analytical and numerical calculations, and the influences of wind, the leakage resistance and the object arrangement on the ion trajectory and electrification quantities are discussed.