Method for measuring the electric field strength under UHV/EHV AC/DC parallel transmission lines

Abstract

In the measurement of hybrid electric field strength such as electric field under UHV/EHV AC/DC parallel transmission lines, simultaneous measurement of direct current component and ac electric field components is a key problem to be solved. In this paper, an improved method for AC/DC hybrid field strength measuring device (rotary voltmeter) is proposed, and a type of Bernoulli curve stator is designed. After using the new structure, when the rotor is rotating, the stator area exposed to the electric field changes sinusoidally. The mathematical expression of the change of the area is derived from the principle of mathematics, based on this, the spectral characteristics of the output of the measuring equipment under the AC and DC hybrid electric fields are studied. In addition, the corresponding relationship between the AC/DC electric field and the spectrum of the result of the measurement is established. This paper presents a method of measuring the ground electric field of AC/DC parallel transmission lines considering both AC/DC components. A calibration experiment is carried out in DC electric field, which verifies the accuracy and effectiveness of the method.