The measurement of ion mobility is important for calculating the corona loss of the transmission lines

and for establishing corona loss and ion current models that take humidity and air pressure into consideration. This paper describes a needle-ring corona discharge experiment setup based on a prior study

which simulates different humidity and air pressure conditions; it is observed that the execution of the ion gate is improved in this experiment from off-on-off to off-on to achieve higher ion current amplitude. Additionally

positive and negative ion mobility under different humidity and air pressure is obtained

with the positive ion mobility measurements in the range of 1.1126 to 1.9167 cm

2

/V·s

and the negative ion mobility measurements in the range of 1.3574 to 2.5643 cm

2

/V·s. The experimental results indicate that ion mobility decreases nonlinearly with increase in humidity

but trends towards saturation in the 30%-70% relative humidity range. Finally

a parameter correction method for calibrating the relationship among the ion mobility

humidity

and air pressure is proposed.