Optical Voltage Transformer with Closed-Loop Feedback
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Solution Overview
Problem
Existing optical voltage transformers face issues such as light source wavelength drift, optical power instability, large size, high cost, partial discharge, and reliability concerns due to temperature changes and mechanical instability, limiting their accuracy and safety in high-voltage applications.
Innovation Solution
An electro-optic effect-based optical voltage transformer with an optical closed-loop feedback control unit and a signal processing unit, integrated within GIS cavities or tank-type structures, utilizing a BGO crystal and SLD light source for stable light source output and improved signal demodulation, along with gas-tight optical fiber extraction and SF6 insulation for reduced complexity and enhanced safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional electromagnetic inductive or capacitive voltage divider transformer is used, then insulation design is complex and bandwidth is limited, but the structure is proven and reliable
Solution Approach 1:
The patent replaces the traditional electromagnetic inductive or capacitive voltage divider with an optical measurement system using the Pockels effect. The high-voltage signal is transmitted to secondary equipment via optical fiber, substituting electrical field-based measurement with optical field-based measurement, thereby simplifying insulation design and expanding bandwidth.
Solution Approach 2:
The patent introduces optical fiber as an intermediary medium to transmit the high-voltage signal from the primary side to the secondary equipment. This intermediary converts the electrical signal to optical signal, eliminating the need for complex electrical insulation design while maintaining signal transmission capability.
2Measurement precision
If longitudinal modulation structure based on Pockels electro-optic effect is used, then measurement accuracy reaches IEC 0.2 level, but insulation cost under high voltage is high and signal demodulation is difficult
Solution Approach 1:
The patent inverts the traditional longitudinal modulation structure and adopts a horizontal modulation structure where the BGO crystal is modulated horizontally by the electric field. This inversion simplifies the optical path design, makes signal demodulation more straightforward, and reduces insulation requirements while maintaining measurement accuracy.
3Ease of manufacture
If multiple discrete optical components are bonded together, then the optical system can be assembled, but micro outward movement during curing process affects azimuth accuracy
Solution Approach 1:
The patent merges multiple discrete optical components (collimators, polarizer, BGO crystal, analyzer) into a integrated optical module with a unified structure. This integration eliminates the need for separate bonding processes between components, preventing micro outward movements during curing and maintaining precise azimuth alignment.
4Reliability
If additional insulation design is added for GIS cavity integration, then withstanding voltage is improved, but system complexity and cost increase
Solution Approach 1:
The patent designs the optical voltage transformer housing to serve multiple functions: it provides structural support for the optical components, acts as the GIS cavity integration interface, and provides the necessary insulation for withstanding high voltage. This multi-functionality eliminates the need for separate additional insulation designs, reducing system complexity while maintaining reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution stabilizes light source output, enhances measurement accuracy, reduces system complexity, and improves reliability and safety by eliminating partial discharge and withstanding voltage issues, while offering flexible, compact, and cost-effective designs for various voltage levels.
Implementation Method 1
their principles of work are all using the longitudinal modulation structure based on Pockels electro-optic effect
Data Source
AI summary
An electro-optic effect based optical voltage transformer comprises an optical voltage sensor head and an electrical unit, wherein the electrical unit comprises an optical closed-loop feedback control unit and a signal processing unit, the optical closed-loop feedback control unit is connected to the optical voltage sensor head and the optical voltage sensor head is connected to the signal processing unit. In this invention, the light source output power is more stable, the light source center wavelength drift is effectively controlled and the output power coastdown caused by light source aging is prevented; the optical power fluctuation of the optical polarization caused by factors such as temperature, optical fiber vibration, etc., is eliminated, which is conductive to stability and reliability of the optical system; the accuracy of data is improved.