Differential Structure to Improve Performance of DC Electric Field Sensors

The electric field is an essential electromagnetic environmental parameter in designing and constructing high-voltage direct-current (HVDC) transmission lines. In this article, a differential structure is proposed to improve the performance of the field mill sensor. Two groups of vanes with the same characteristics generate induced currents with opposite phases, and the difference operation calculates the ground electric field. We calculated the charges and induced currents and optimized the number of vanes of the sensing electrode using the simulation model. Then, we designed the
${I}/{V}$
circuit and amplifier based on the differential structure and conducted circuit simulation and sensor calibration experiments. Compared with the single input electric field sensor, the noise of the sensor with the differential structure is significantly reduced, and the sensitivity reaches 0.085 V/(kV/m). The results indicate that the field mill sensor with improved differential structure enhances the anti-interference ability and sensitivity.