Optical Fiber Current Transformer Temperature Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional optical fiber current transformers suffer from low accuracy in current measurement due to temperature effects such as variations in magneto-optical coefficients, fiber optic wave plate retardation, internal strain, and temperature effects on analog circuit devices, leading to inaccurate current readings.
Innovation Solution
An optical fiber current transformer with fiber optic temperature acquisition and two-temperature source compensation, utilizing a broadband light source, depolarizer, beam splitter, temperature acquisition unit, current acquisition unit, modulation waveform generating unit, data processing unit, and calculating compensation unit, which derives a compensation factor from pre-calibrated temperature-current compensation curves to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical fiber current transformer is used without temperature compensation, then the device complexity is low, but the measurement precision deteriorates due to temperature effects
Solution Approach 1:
The system is divided into separate functional modules: temperature acquisition unit with temperature sensing element, current acquisition unit with photoelectric detector, and calculating compensation unit with compensation curve storage. Each module independently performs its specific function, allowing for modular implementation that improves measurement precision while keeping individual module complexities manageable.
Solution Approach 2:
The compensation curves are pre-calibrated and stored in the calculating compensation unit before actual measurement operations. This preliminary preparation of compensation data allows the system to quickly apply temperature compensation during operation without performing complex calculations in real-time, thereby improving measurement precision while maintaining reasonable device complexity.
2Measurement precision
If dual-mode processing with separate temperature and current processors is implemented, then the measurement precision improves to 0.1%, but the device complexity increases
Solution Approach 1:
The processing functions are segmented into two separate processors: a data processing unit that handles current measurement data and a calculating compensation unit that handles temperature compensation calculations. This segmentation allows each processor to be optimized for its specific task, achieving 0.1% measurement precision through specialized processing while managing overall system complexity through clear functional separation.
Solution Approach 2:
The calculating compensation unit receives temperature data from the temperature acquisition unit and applies compensation based on pre-stored curves. This feedback mechanism continuously corrects measurement errors caused by temperature variations, improving real-time current measurement accuracy to 0.1% while using a relatively simple lookup-based compensation approach rather than complex real-time calculations.
3Measurement precision
If optical fiber temperature acquisition and two-temperature source compensation are implemented, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The temperature measurement function is segmented into a dedicated temperature acquisition unit with temperature sensing element that operates independently from the current measurement path. This unit acquires two temperature values (first and second temperature values) and provides them to the calculating compensation unit, enabling precise temperature compensation while maintaining a clean separation between temperature and current measurement functions.
Solution Approach 2:
The system uses two different temperature sensing elements that measure different temperature parameters (first temperature value and second temperature value). By acquiring multiple temperature parameters and using pre-calibrated compensation curves, the system can more accurately compensate for temperature effects on the magneto-optical coefficient and other temperature-sensitive parameters, thereby improving measurement precision.
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 achieves high accuracy in current measurement up to 0.1%, facilitates high-voltage insulation, modularization for easy fault detection, and enhances system response time in tri-phase systems, making it suitable for high-voltage and high-current power networks.
Implementation Method 1
The temperature acquisition unit acquires two digital temperatures DT1 and DT2 from the temperature sensing element and delivers DT1 and DT2 to the calculating compensation unit. In the temperature acquisition unit, there is a temperature sensing element, which is based on a principle of birefringence-temperature effect of polarization maintenance fiber.
Implementation Method 2
The optical fiber current transformer is based on the Ampere's law and Faraday magneto-optical effect. It can indirectly measure the current value by measuring the phase difference, induced by the current magnetic field, between two orthogonally polarized light beams transmitting in the sensing fiber.
Data Source
AI summary
An optical fiber current transformer includes a broadband light source, a depolarizer, a beam splitter, a temperature acquisition unit, a current acquisition unit, a modulation waveform generating unit, a data processing unit and a calculating compensation unit. The broadband light source is connected with the beam splitter by the depolarizer. A first output of the beam splitter is connected with the calculating compensation unit by the temperature acquisition unit. A second output of the beam splitter is connected with the data processing unit by the current acquisition unit. The data processing unit is connected with the calculating compensation unit. The calculating compensation unit is connected with the current acquisition unit by the modulation waveform generating unit. The optical fiber current transformer uses the temperature-current compensation curve in the calculating compensation unit to synchronously process the temperature and current, thereby improving the accuracy of real-time current measurement.