Non-magnetic Sensor Coil Dielectric Capacitive Coupling
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Solution Overview
Problem
Existing current sensor devices in utility meters, such as transformer and Rogowski coils, face accuracy issues due to external magnetic fields and temperature cycles, leading to high costs and extended calibration processes, especially during low or high current conditions.
Innovation Solution
A utility meter with a sensor device featuring a non-magnetic substrate coil and a dielectric material with a specific dielectric constant positioned between the coil and conductor, reducing capacitive coupling and requiring only one calibration coefficient for a wide current range, from 2.0 A to 25,000 A.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transformer sensor devices with magnetic cores are used, then current sensing capability is provided, but the device becomes bulky and expensive, and accuracy is reduced due to external magnetic fields and temperature cycles
Solution Approach 1:
The patent removes the magnetic core from the sensor device, extracting the source of magnetic susceptibility while retaining current sensing capability through air-core or non-magnetic core construction. This eliminates the harmful interaction with external magnetic fields and temperature-induced magnetic drift.
Solution Approach 2:
The patent introduces a non-magnetic substrate and shielding structures as intermediaries between the sensing coil and external magnetic fields. These elements protect the sensing mechanism from external interference without requiring magnetic materials that would be susceptible to field effects.
2Volume of moving object
If Rogowski coils are used, then device size is reduced, but accuracy is limited during low current and high current conditions requiring multiple calibration processes
Solution Approach 1:
The patent modifies the coil structure parameters including turn density, winding configuration, and aperture geometry to optimize performance across the full current range. By carefully controlling these parameters, the sensor achieves accurate measurement from low to high currents without requiring multiple calibration coefficients.
Solution Approach 2:
The patent designs a universal sensor structure that performs accurately across diverse operating conditions (low current, high current, various voltages) using a single calibration coefficient. The design achieves multi-functionality in terms of current range coverage without sacrificing precision at any specific operating point.
3Manufacturing precision
If multiple calibration processes are applied to Rogowski coils, then manufacturing accuracy is improved, but manufacturing time and costs increase
Solution Approach 1:
The patent incorporates preliminary design features during manufacturing that ensure consistent performance across all units. By pre-configuring the coil geometry, turn count, and aperture dimensions with high precision during fabrication, the need for repeated calibration processes is eliminated, achieving both accuracy and high productivity.
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
This configuration enhances accuracy and simplifies calibration, reducing manufacturing time and costs while maintaining consistent current sensing across varying voltages and currents, and provides improved immunity to external electromagnetic interference.
Implementation Method 1
The dielectric constant of the dielectric material is selected to reduce a capacitive coupling between the coil and the conductor
Implementation Method 2
a coil comprising a plurality of turns wound about the substrate where the coil defines an aperture through which the conductor is to be received
Data Source
AI summary
A utility meter and related methods are disclosed. The utility meter includes a sensor device positioned around a conductor to sense current flowing through the conductor. The sensor device includes a non-magnetic substrate, a coil comprising a plurality of turns wound about the substrate, and a dielectric material having a dielectric constant and positioned between the coil and the conductor. The utility meter also includes a meter control board in communication with the sensor device to determine an amount of electricity transmitted through the conductor from the power source to the user over time. The dielectric constant of the dielectric material is selected to reduce a capacitive coupling between the coil and the conductor and to reduce a sensitivity of the sensor device such that the meter control board comprises only one calibration coefficient for calibrating the sensor device over a current range.