Measurement of Space Potential Distribution Around Overhead HVDC Transmission Lines Based on Potential Compensation on Suspended Conductor

Abstract

An ion-flow field is very important for the design of an HVDC transmission line. Due to the space ions resulting from corona discharge, there are few practical methods to measure the space electric fields around HVDC transmission lines. In this paper, a compensation method is presented to measure the space potential in the ion-flow field. The space potential can be obtained by applying an adjustable voltage source to a suspended conductor, increasing the voltage step-by-step and measuring the current flowing through the voltage source or the ground-level ion current density under the suspended conductor. When the current is equal to zero or the ground-level ion current density is equal to that without the suspended conductor, the output voltage of the voltage source is the space potential to be measured. The paper first introduces the principle of the measurement method. Then, the feasibility of the method is testified on unipolar and bipolar reduced-scale models. Finally, the measured results are discussed and are compared with the results by the numerical method.