An Experimental Study on the Mobility Characteristics of Corona Ions Produced by a HVDC Test Line

This paper reports experimental results of the continuous mobility spectrum and mean mobility of corona ions by using a Gerdien tube and the integral equation method. The effects of voltage polarity, nominal electric field on the conductor surface, temperature, humidity and airborne suspended particles on the mobility spectrum and mean mobility are studied. The results show that the positive and negative mean ion mobilities are 1.06 -1.20 cm2V−1s−1 and 1.74-2.04 cm2V−1s−1, respectively, when the temperature is 25 °C and the relative humidity (RH) is 20%. The electric field on conductor surface has little impact on the mean ion mobility in the range of +23.1-+28.2 kV/cm and -20.5–25.6 kV/cm, while increasing temperature and humidity leads to a decrease of the negative mean ion mobility. The results also show that airborne suspended particles have impacts on the mean ion mobility and mobility spectrum, and the impacts are density reliant, which are ascribable to the capture of ions by particles, leading to the variation of the weights of all ion species in the spectrum.