Non-Contact Voltage Reconstruction Method Based on Dual-Pin Type Probes Structure and Measuring Point Optimization for AC Overhead Transmission Lines

With increasing requirements for online monitoring of overhead transmission lines (OTLs) in smart grids, contact-free measurement technologies have been updated these decades. However, the contactless sensors in past research are still limited to the application environment like wind deflection. This article proposes an advanced detection approach with a novel structure to enhance the possibility of implementation and reduce cost. Three pairs of detection probes arranged in a curved pattern can collect differential voltage signals based on the principle of electric field radiation. With three-phase vector decomposition, the nine unknown variables including the voltage to be measured and the status of lines (sag and wind deflection) in nine equations can be constructed. The voltages to be measured can be calculated by solving this nonlinear equation system by iteration. Also, the position of the device installation is optimized by the particle swarm optimization (PSO) algorithm regarding accuracy. The whole measurement device can be easily implemented on the towers according to the distance of insulation requirement regardless of the position of lines. The simulation of level 110 kV is investigated and a model system is built to measure a lower-level voltage for verification. The results show that the proposed non-contact OTL voltage approach can reach the desired accuracy with low costs and monitor the status of lines.