Optical Voltage and Current Measuring System for Electric Power Systems

To achieve linear measurement of electro-optic phase delay and improve the accuracy and measurement range of the optical voltage transducer (OVT), this paper proposes a linear phase delay detection method for an optical voltage transformer based on a strip S-wave plate. Using the strip S-wave plate, the phase delay can be directly converted into the displacement of the dark stripe of the strip spot, and the displacement is located by the dual-quadrant detector. Using the Jones matrix, we confirm the linear relationship between the position of the dark stripe and the phase delay, and propose a positioning method and error compensation scheme of the dark stripe and set up an experimental system to verify its performance. The experimental results show that the OVT realizes the measurement of the electro-optic phase delay; the measuring range of the phase delay is up to ±40°, and the measurement error is less than 0.5%.

Section: Introductionmentioning

confidence: 99%

Linear phase delay detection method for optical voltage transformer based on S-wave plate

Xie¹,

Zhu²,

Xu³

et al. 2021

“…An optical voltage sensor (OVS) can be modulated in a transverse or longitudinal mode [1][2][3][4]. The pertinent advantages of the transverse mode are therefold: the half-wave voltage can be adjusted in accordance with electro-optic crystal dimensions; the design of the electrodes is simple; and the structure is compact and easy to install [5][6][7][8][9]. However, the measurement accuracy and stability are susceptible to the external electric field non-uniform distributions [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Pockels electric field in transverse modulated optical voltage sensor

Huang¹,

Xu²,

Chen³

et al. 2018

This paper investigates the possibilities of optimizing the Pockels electric field in a transverse modulated optical voltage sensor with a spherical electrode structure. The simulations show that due to the edge effect and the electric field concentrations and distortions, the electric field distributions in the crystal are non-uniform. In this case, a tiny variation in the light path leads to an integral error of more than 0.5%. Moreover, a 2D model cannot effectively represent the edge effect, so a 3D model is employed to optimize the electric field distributions. Furthermore, a new method to attach a quartz crystal to the electro-optic crystal along the electric field direction is proposed to improve the non-uniformity of the electric field. The integral error is reduced therefore from 0.5% to 0.015% and less. The proposed method is simple, practical and effective, and it has been validated by numerical simulations and experimental tests.

“…Faraday-effect-based optical current transformers (OCTs) have become important in the electrical power industry because of their non-contact, highly insulating and fibre-remote sensing features [1,2]. Most requirements on OCTs for the electrical power industry lie in the measurements of heavy currents (>10 A) in power cables or small currents (<1 A) such as zero phase or leakage currents.…”

Section: Introductionmentioning

confidence: 99%

A very sensitive Faraday effect current sensor using a YIG/ring-core transformer in a transverse configuration

Yoshino¹,

Minegishi²,

Nitta³

2001

A new and unusual type of Faraday cell/ring-core optical current transformer characterized by a transverse configuration of the light beam and current-induced magnetic field is developed. A fibre-linked current sensor system is constructed using a small bulk yttrium iron garnet as the Faraday cell. It is shown that the sensor has the highest ever reported sensitivity of about 20% A-1 in modulation depth of the output light power with a very good linearity for currents below 1 A and has a very good isolation from surrounding currents.