Cable Power Sensing via Residual Magnetic Field Calibration
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Solution Overview
Problem
Conventional energy monitoring systems require direct electrical contact and complex installations to measure power consumption and generation, which is impractical and costly, especially in environments where access to individual conductors is limited, such as in standard AC cables with equal and opposing current flows.
Innovation Solution
A method using residual magnetic fields generated by current flowing through conductors in AC cables, measured by a sensor device equipped with a magnetometer, to determine power delivery without physical contact, leveraging calibration data from smart meters for accurate power calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct electrical contact is used to measure power, then measurement accuracy is improved, but installation complexity and safety risks increase
Solution Approach 1:
The patent replaces direct electrical contact (mechanical/electrical connection) with magnetic field sensing. Instead of inserting current transformers or shunt resistors into the circuit, the system uses magnetometers to detect the magnetic field generated by current flow in the cable, thereby measuring power without physical contact with conductors.
Solution Approach 2:
The patent introduces magnetic field sensing as an intermediary between the current-carrying cable and the measurement system. The magnetometer detects the magnetic field produced by the cable's current, which serves as an intermediate physical quantity that can be measured without direct electrical contact, thus resolving the contradiction between accuracy and installation complexity.
2Measurement precision
If current transformers or shunt resistors are used for current measurement, then measurement accuracy is improved, but component cost and circuit complexity increase
Solution Approach 1:
The patent substitutes traditional electrical measurement components (current transformers, shunt resistors) with magnetic field sensing technology. The magnetometer directly senses the magnetic field around the cable, eliminating the need for these complex electrical components and their associated circuitry.
Solution Approach 2:
The patent extracts the measurement function from the electrical circuit itself. Instead of inserting measurement components into the circuit, the system measures the external magnetic field produced by the circuit's current, thereby taking out the measurement process from the powered circuit and avoiding added complexity.
3Measurement precision
If power meters are placed in-line with load circuits, then power measurement is achieved, but installation difficulty and safety risks increase
Solution Approach 1:
The patent replaces in-line electrical connection with external magnetic field sensing. The magnetometer is positioned around the cable to detect the magnetic field, eliminating the need to break or modify the electrical circuit for measurement purposes.
Solution Approach 2:
The magnetic field serves as an intermediary that allows measurement without direct circuit intervention. The magnetometer detects this intermediate field quantity, enabling power measurement while maintaining the integrity and continuity of the original electrical circuit.
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
Enables non-invasive, safer, and easier installation of energy monitoring systems, providing accurate power measurements by calculating the residual magnetic field's proportionality factor, thus overcoming the limitations of traditional voltage and current sensors.
Implementation Method 1
receiving data related to the residual magnetic field produced by the cable
Data Source
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AI summary
Described embodiments generally relate to a method of determining power delivered by a cable, the method comprising receiving data related to a residual magnetic field produced by the cable; determining a proportionality factor relating the received data to the power delivered by comparing the residual magnetic field data to independently measured reference data related to the power delivered by the cable; and based on the proportionality factor, determining the power delivered by the cable.