Impact of Mechanical Errors on the Sensitivity of Electric Field Sensors

Field mill electric field sensors have been extensively employed for electric field measurements surrounding power transmission lines. Nevertheless, their practical application is constrained by inherent sensitivity variations. This study investigates the impact of mechanical errors on sensor sensitivity through systematic analysis. Theoretical derivation reveals that the sensor's sensitivity exhibits direct proportionality to the DC component of the absolute induced current. Three critical mechanical parameters are identified for characterization: shielding-sensing electrode tilt angle, radial displacement between shielding and sensing electrode centers, and inter-electrode distance. Comprehensive numerical simulations and experimental validations demonstrate that inter-electrode distance constitutes the dominant factor governing sensitivity characteristics, showing an inverse correlation with sensitivity magnitude. These findings suggest that structural optimization focusing on dimensional consistency of d is essential for achieving improved sensitivity uniformity in field mill sensor applications.