Utility Meter Hall Sensor Detection for Magnetic Tampering
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Solution Overview
Problem
Electric utility meters are susceptible to magnetic field tampering, which leads to inaccurate power consumption measurements, causing revenue loss for service providers.
Innovation Solution
Incorporating a three-axis Hall Effect sensor and a controller in the electric utility meter to detect and monitor magnetic fields, logging tamper events when the field strength exceeds a threshold, and generating alerts or logging events for tampering detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an external magnet is placed near the electric utility meter, then the magnetic field strength increases, but the current transformers become saturated and measurement accuracy decreases
Solution Approach 1:
The patent introduces a magnetic field sensor as an intermediary device that detects the presence and strength of external magnetic fields. This sensor acts as a mediator between the external magnet and the current transformers, allowing the system to detect tampering attempts without the magnet directly affecting the measurement circuitry. The sensor provides early warning before saturation occurs.
Solution Approach 2:
The magnetic field sensor performs preliminary detection of external magnetic fields before they can cause saturation of the current transformers. By continuously monitoring magnetic field strength and comparing it against threshold values, the system takes preliminary action to alert operators of potential tampering attempts, preventing the harmful effect from occurring in the first place.
2Reliability
If a magnetic field sensor is added to detect tampering, then tamper detection capability improves, but device complexity increases
Solution Approach 1:
The magnetic field sensor is designed to serve multiple functions: detecting the presence of external magnets, measuring magnetic field strength, and providing tamper alerts. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in overall device complexity while maintaining high reliability.
Solution Approach 2:
The sensor system is integrated into the existing meter architecture and uses the meter's own processing capabilities to analyze sensor data and generate alerts. The system serves itself by using the meter's existing resources (processor, memory, display) to handle the additional detection function, minimizing the need for separate external equipment and reducing overall system complexity.
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
Effectively detects and logs magnetic tampering events, reducing inaccuracies in power consumption measurements and alerting service providers, thereby preventing revenue loss.
Implementation Method 1
a sensor configured to detect a magnetic field proximate the electric utility meter
Data Source
AI summary
An electric utility meter including a Hall Effect sensor configured to sense a magnetic field proximate the electric utility meter. The electric utility meter also includes a controller having an electronic processor, the controller configured to receive a signal indicative of a magnitude of the magnetic field proximate the electric utility meter from the sensor, determine whether the magnitude of the magnetic field exceeds a first magnitude threshold and whether a threshold flag has been set, set the threshold flag when the threshold flag has not been set and the magnitude exceeds the first magnitude threshold, determine an amount of time for which the magnitude has exceeded the first magnitude threshold when the threshold flag has been set, and generate an alert indicative of a magnetic tamper event when the amount of time exceeds a time threshold.