Meter Temperature Sensing with Dynamic Thresholds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electricity meters face challenges in reliably detecting deterioration of high-power switch contacts and arcing issues due to resistance and temperature measurement inaccuracies, particularly in designs with insulators or air gaps, which can lead to false positives and increased material costs.
Innovation Solution
A utility meter with a temperature sensor and processing circuit that uses compensated temperature measurements to determine if an overheat condition exists, accounting for self-heating and ambient temperatures, and adjusts thresholds based on time of year and day to accurately detect abnormal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature sensor is attached to a mass in thermal contact with the electrical connection to detect overheating, then the detection capability is improved, but the device complexity and material cost increase due to requiring additional thermal contact structures
Solution Approach 1:
The existing current coil serves dual purposes: its primary function of electrical measurement and its secondary function as a thermal mass for temperature sensing. The current coil's inherent thermal properties are utilized to detect overheating conditions without requiring separate sensing structures, thereby reducing device complexity while maintaining detection capability
Solution Approach 2:
The current coil is designed to perform multiple functions simultaneously: electrical current measurement and temperature sensing. By making the temperature sensor utilize the thermal mass of the current coil, the system achieves multi-functionality, eliminating the need for separate thermal contact structures and reducing overall device complexity
2Object-affected harmful factors
If a temperature sensor is isolated from the electrical connection by an insulator or air gap, then the safety and electrical isolation are improved, but the measurement precision deteriorates due to temperature distortion from ambient conditions
Solution Approach 1:
The current coil acts as an intermediary between the electrical connection and the temperature sensor. It provides thermal coupling to transfer heat from the electrical connection to the sensor while maintaining electrical isolation through the air gap or insulator, thus mediating between the conflicting requirements of thermal contact and electrical isolation
Solution Approach 2:
The system separates the thermal path from the electrical path. The temperature sensor is positioned in thermal contact with the current coil but electrically isolated by an air gap or insulator, creating distinct thermal and electrical pathways that allow independent optimization of each function
3Reliability
If a high temperature threshold is used to avoid false positives from ambient temperature and normal operations, then the false positive rate is reduced, but the detection sensitivity deteriorates requiring higher temperatures to trigger maintenance alerts
Solution Approach 1:
The threshold is made dynamic rather than static, varying with ambient temperature conditions. By adjusting the threshold based on ambient temperature, the system maintains high sensitivity across different operating conditions while avoiding false positives, as the threshold adapts to the current thermal environment
Solution Approach 2:
The temperature threshold parameter is changed from a fixed value to a variable that depends on ambient temperature. This parameter change allows the system to maintain optimal detection sensitivity across different environmental conditions while filtering out normal operational temperature variations
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 solution enables efficient and reliable detection of maintenance issues in electricity meters, reducing false positives and material costs while effectively identifying overheating malfunctions, thus improving maintenance efficiency and accuracy.
Implementation Method 1
a temperature sensor disposed within the meter housing that generates a sensor signal based on a temperature within the meter housing
Implementation Method 2
The current coil can be coupled to receive heat energy from a meter socket
Data Source
AI summary
A utility meter includes a meter housing that supports at least one current coil, a temperature sensor, and a processing circuit coupled to both. The current coil can be coupled to receive heat energy from a meter socket. The temperature sensor disposed generates a sensor signal based on a temperature within the meter housing. The processing circuit obtains the sensor signal and generates meter temperature information based at least in part thereon. The processing circuit also obtains a first predetermined threshold based on at least one of time of day information and date information. The processing circuit also determines whether an abnormal condition exists by comparing the meter temperature information to a value based on the first predetermined threshold, and generates an output signal to a memory, display or communication circuit responsive to determining that the abnormal condition exists.