Optical Field Sensor Using Zeeman Gas for Temperature-Independent Measurement
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Solution Overview
Problem
Current measurement devices for electric and magnetic fields in high voltage transmission networks are susceptible to temperature variations and mechanical stress, particularly when installed at height, and are unable to accurately measure direct current transmission.
Innovation Solution
A device utilizing a measuring cell with a gas sensitive to the Zeeman or Stark effect, combined with polarimetry and absorption measurement systems, to measure electric and magnetic fields, which compensates for temperature variations and is robust enough for installation in harsh environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Pockels effect electric field sensor is used, then electric field measurement is enabled, but temperature variations affect measurement accuracy
Solution Approach 1:
The patent introduces a second light beam as an intermediary reference that does not interact with the gas in the measuring cell. This reference beam serves as a temperature-compensated baseline, allowing the system to distinguish between true electric field effects and temperature-induced measurement drift by comparing the signal beam's changes against the stable reference beam.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors temperature variations through the reference beam and adjusts the measurement accordingly. The processing unit uses the reference beam's intensity changes (caused by temperature) to compensate for and eliminate temperature-induced errors in the electric field measurement.
2Measurement precision
If a Faraday effect sensor is used, then current measurement is enabled, but temperature dependence requires correction
Solution Approach 1:
The patent uses a reference light beam as an intermediary that passes through the same gas cell but does not experience the Faraday effect. This reference beam serves as a temperature reference, allowing the system to separate temperature effects from the magnetic field-induced Faraday effect in the signal beam.
Solution Approach 2:
The system employs feedback by continuously monitoring the reference beam's intensity changes caused by temperature variations and using this information to compensate for temperature-induced errors in the Faraday effect measurement, thereby maintaining accurate current measurement across varying temperatures.
3Measurement precision
If a Hall effect detector is used, then current and voltage detection is enabled, but temperature correction is still required
Solution Approach 1:
The patent introduces a reference light beam as an intermediary that does not interact with the magnetic field but does experience temperature effects. This allows the system to measure temperature-induced changes separately from the Hall effect signal, enabling temperature-compensated current and voltage detection.
Solution Approach 2:
The system uses the reference beam as feedback to monitor temperature variations and compensates for their effect on the Hall effect detector readings. The processing unit adjusts the measurement based on the reference beam's temperature-induced changes, eliminating temperature sensitivity from the final current and voltage measurements.
4Measurement precision
If inductive transformers are used for measurement, then voltage and current measurement is enabled, but the device cannot measure direct current
Solution Approach 1:
The patent replaces the electromagnetic induction-based mechanical/electromagnetic system with an optical measurement system. By using light beams interacting with gas atoms through the Zeeman and Stark effects, the system can measure both alternating and direct current, eliminating the fundamental limitation of inductive transformers that only work with alternating current.
Solution Approach 2:
The patent changes the fundamental measurement parameter from electromagnetic induction to optical interaction. By measuring changes in light polarization and intensity caused by the Zeeman effect (magnetic field) and Stark effect (electric field), the system can detect both AC and DC components, thereby changing the adaptability parameter to support multiple measurement modes.
5Measurement precision
If windings are used to surround the electrical conductor, then measurement is enabled, but mechanical stress on supports increases
Solution Approach 1:
The patent substitutes the mechanical winding structure with an optical measurement system. Instead of physically surrounding the conductor with windings that exert mechanical stress, the system uses light beams passing through a gas cell to measure electric and magnetic fields, completely eliminating the mechanical stress problem while maintaining measurement capability.
Solution Approach 2:
The patent introduces a gas-filled measuring cell as an intermediary between the electrical conductor and the optical detection system. This intermediary allows non-contact measurement of electric and magnetic fields through optical interaction with gas atoms, eliminating the need for mechanical windings and their associated stresses on supports.
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 device provides accurate and temperature-independent measurements of electric and magnetic fields, overcoming previous limitations and ensuring reliable operation in varying climatic conditions and mechanical stress scenarios.
Implementation Method 1
a measuring cell (3) containing a gas sensitive to the Zeeman and/or Stark effect, in particular an alkali gas, and intended to be placed in a magnetic and/or electric field
Implementation Method 2
a measuring cell (3) containing a gas sensitive to the Zeeman and/or Stark effect, in particular an alkali gas, and intended to be placed in a magnetic and/or electric field
Implementation Method 3
at least one polarimetry system configured to measure a first parameter corresponding to the rotation by a polarization angle due to the passage of the beam through the measuring cell containing a gas sensitive to the Zeeman and/or Stark effect
Implementation Method 4
an absorption measuring system configured to measure a second parameter corresponding to the absorption of the beam by the gas sensitive to the Zeeman and/or Stark effect in the measuring cell
Data Source
Figure 1~2b
Figure 3~4B
Figure 5~6
AI summary
The present invention relates to a device (1) for measuring a magnetic field (B) and/or an electric field (E) comprising: - a measurement cell (3) enclosing a gas that is sensitive to the Zeeman effect and/or to the Stark effect, a polarised light source (7) the wavelength of which is tuned to an absorption line of the gas that is sensitive to the Zeeman effect and/or to the Stark effect, - at least one polarimetry system (11) configured to measure a first parameter corresponding to the rotation by a polarisation angle caused by the passage of the beam (9) through the measurement cell (3) enclosing a gas that is sensitive to the Zeeman effect and/or to the Stark effect, - a system (13) for measuring absorption, configured to measure a second parameter corresponding to the absorption of the beam (9) by the gas that is sensitive to the Zeeman effect and/or to the Stark effect in the measurement cell (3), and a processing unit (15) configured to combine the measurement of the first parameter corresponding to the rotation by the polarisation angle and the absorption measurement in order to extract therefrom a third and/or fourth parameter corresponding respectively to an electric field (E) and/or a magnetic field (B) to be measured.