Impact factors in calibration and application of field mill for measurement of DC electric field with space charges

The DC electric field is sometimes accompanied by space charges caused by the partial discharge in the air, which impacts DC electric field measurements. This paper describes the impact factors in the calibration and application of the field mill for measuring the DC electric field with space charges. First, the influence of the space charges on calibration results is evaluated and discussed. Then, both the impact of the height of the meter probe above the ground and the touch resistance between the ground and the meter on the measurement results are investigated. Correct calibration and application methods are presented. The results are expected to be of use to engineers for conducting accurate measurements of the DC electric field with space charges.