Study on assessment and countermeasures of induced voltage on distribution lines under EHV/UHV transmission lines

Due to the lack of transmission corridor, high-voltage transmission lines are often inevitably parallel or nearly parallel to the low-voltage distribution lines. Under distribution line maintenance conditions, high induced voltage may exit on distribution lines. If no appropriate measures are taken, the maintainers of distribution lines will be in danger. In this paper, EMTP models are adopted to calculate the induced voltages on distribution lines under EHV/UHV AC and DC transmission lines. A new induced-voltage elimination device for field application is proposed. The effect of load current of high-voltage transmission lines and the parallel length of HV lines with distribution lines on the induced voltage are slight, while the effect of offset distance between the distribution lines and HV lines tower center is significant. Induced voltages on distribution lines increase with the increase of voltage level of HV transmission lines, and they are much larger under AC lines than under DC lines. The designed elimination device can eliminate induced voltage on distribution lines effectively, and thus ensure the personal safety of maintenance workers without increasing the workload.