A Measurement Method for the Charging Potential of Conductors in the Vicinity of HVDC Overhead Lines Based on a Non-Contact Electrometer

Charging potential appears when a conductor insulated to the ground is exposed to an electrostatic field. A modified measurement method based on a non-contact electrometer is presented in this article. This system is appropriate for measuring the charging potential of a conductor near high-voltage direct-current (HVDC) overhead lines. Compared with the contact measurement method, the modified method is hardly affected by the internal resistance of the electrometer, which helps ensure measurement accuracy in the electrostatic field. In contrast with the traditional non-contact electrometer, the electric field generated by HVDC lines and the space charges around the electrometer probe are shielded using a grounding cage. The effectiveness of the modified measurement method was verified via experiments. The impacts of the structure and position of the measurement system on the measured charging potential are discussed.