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In this study, a long‐distance non‐contact current measurement method is proposed based on the non‐contact sensor array measurement technology, combined with a new current algorithm. The sensor array is a vertical array composed of three three‐axis magnetic field (MF) sensors that is placed on the ground plane below the measured overhead line. The proposed current algorithm can optimize the geometry of the overhead line using the spatial MF values measured by the sensor array and then the three‐phase currents can be calculated. To improve the accuracy of current measurement, the spatial MF model in the algorithm considers the influence of cable sag. It enables a more accurate coupling matrix between the measured overhead line and the sensor array to be established. Additionally, the current algorithm architecture is designed using a composite algorithm to more optimally obtain the best three‐phase current values. A scale‐down overhead‐line measurement system is developed to test the proposed current measurement method. The results show whether a cable sag exists when the three‐phase currents are approximately balanced, with errors less than 2.0%. Moreover, it can be determined whether cable sag exists when the three‐phase currents are unbalanced, with less than 3.4% errors. [ABSTRACT FROM AUTHOR]

With the growing infrastructure for overhead lines, the demand for overhead‐line condition‐monitoring technologies has become increasingly urgent. Traditional current transformers used to measure three‐phase currents are bulky and difficult to install, which further increases the cost of monitoring. In order to meet the current state assessment needs of transmission and distribution networks, this study uses a novel magnetic‐field sensor array to realize nonintrusive overhead‐line current detection. Based on the magnetic fields measured by magnetic‐field sensors placed on the ground under the overhead line, the proposed algorithm can be used to calculate the three‐phase current values. The proposed method does not require on‐site calibration before the field measurements are conducted. With partially known overhead‐line geometry specifications from utilities, the algorithm can optimize the overhead‐line geometry and finally achieve accurate current detection. The simulation and experimental results verify that the proposed current‐detection technique can accurately calculate the three‐phase currents of the overhead line with only three three‐axis magnetic‐field sensors. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]