Optical voltage transformer

Abstract

The invention discloses an optical voltage transformer which is composed of a light source, a coupler, a polarizer, a phase modulator, a polarization delay optical cable, a collimating lens, a faraday rotary mirror, an electro-optical sensing unit, a photoelectric detector and a signal processing module, wherein the electro-optical sensing unit is composed of a bismuth germinate and an A and a B electrodes which are respectively installed on an upper and a lower panels of the bismuth germinate. The invention adopts the technical proposal that an electric field leads to the change of the refractive index of the sensing bismuth germinate in the electro-optical sensing unit, the phase difference of two cross-line polarized lights passing through the bismuth germinate is changed due to the Pockels effect, and the magnitude of the electric field can be indirectly measured by measuring two coherent lights.

Description

technical field [0001] The invention relates to a voltage sensor, in particular to an optical voltage transformer. Background technique [0002] Voltage transformer is an important equipment for electric energy measurement and relay protection in power system. Its accuracy and reliability are closely related to the safe, reliable and economical operation of power system. However, with the development of the power industry, the capacity of the power transmission system continues to increase, and the operating voltage level is getting higher and higher. At present, the highest voltage level of my country's power grid has reached 500kV, and it is developing to a higher voltage level. The principle of the traditional electromagnetic voltage transformer is based on the electromagnetic induction similar to the principle of the transformer. Due to its working principle, there are some technical difficulties that are difficult to solve. Such as: [0003] (1) The increase of the vo...

AI Technical Summary

Problems solved by technology

[0003] (1) The increase of the voltage level increases the difficulty of insulation, resulting in complex insulation structure, larger volume and weight, inconvenient installation and transportation, and the cost rises exponentially

[0004] (2) Due to the limited magnetic properties of the iron core, the iron core may be seriously saturated under the action of some large operating voltage or fault voltage, which will cause unacceptable deviations in the measurement results and provide wrong information to the power system

[0005] (3) At present, the traditional voltage transformer is mostly filled with mineral oil as the insulation and heat dissipation medium, and there is a danger of sudden failure that may cause combustion and explosion

[0006] At present, most of the voltage transformers are electromagnetic or capacitive voltage divider voltage transformers, which have defects such as small dynamic range, low sensitivity, and large insertion loss.

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