Contactless voltage sensor for overhead transmission lines

Most traditional voltage transformers in transmission and distribution networks are installed inside the substations. Nearly no accessible voltage information in the real-time scale is available for field engineers to carry out the field measurement for the purposes of the power quality inspection and the equipment maintenance. In order to offer an on-site and easy-to-use solution for the field measurement, the authors propose a novel electric-field (EF) sensor array based technique for measuring the overhead-line voltage. Based on the EFs measured by the EF sensor array and the partially known overhead-line geometry information from utilities, the proposed voltage algorithm can accurately calculate each-phase voltage without an on-site calibration before conducting the field measurement. The simulation results demonstrate that the authors' proposed technique with only three EF sensors can accurately calculate the overhead-line voltages and successfully reconstruct the real-time three-phase waveforms. The experiment results verify the feasibility of the proposed voltage sensor for the overhead-line voltage measurement.