Electric Cable Conductor Temperature Estimation via Outer-Layer Sensing
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Solution Overview
Problem
Existing methods for determining the temperature of an electrical conductor in an electric cable are invasive, costly, or limited to a test phase, and do not allow for continuous monitoring of installed cables.
Innovation Solution
A non-invasive system using temperature sensors on the outer surface of the cable layers and a determination unit that calculates conductor temperature based on peripheral temperature and thermal resistance, optionally with additional layers and sensors, to estimate conductor temperature without modifying the cable structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is placed directly in the vicinity of the conductor, then temperature measurement accuracy is improved, but electrical arcs may occur within the cable structure
Solution Approach 1:
The patent introduces an intermediary approach by using the cable's existing outer layers as a thermal conduction medium. Instead of placing the sensor directly near the conductor, the sensor is positioned on the outer surface of the cable, and the known thermal resistance of the cable layers serves as a mediator to calculate the conductor temperature from the peripheral temperature measurement.
Solution Approach 2:
The patent replaces the direct mechanical placement of the temperature sensor near the conductor with a computational approach. A determination unit uses a physical model incorporating the measured peripheral temperature and the known layer thermal resistance to calculate the conductor temperature, substituting direct thermal contact with mathematical computation.
2Measurement precision
If a test loop with a temperature sensor is used to monitor conductor temperature, then temperature monitoring is improved, but the method can only be performed during the test phase and not on installed cables
Solution Approach 1:
The patent enables the cable structure itself to serve the dual purpose of both electrical conduction and temperature sensing. By utilizing the cable's inherent thermal properties and outer layers, the system allows temperature monitoring without requiring separate test loops or additional infrastructure, making it applicable to both new and installed cables.
Solution Approach 2:
The patent creates a universal temperature monitoring solution that works for both test-phase cables and installed cables. The method uses the cable's existing structure and thermal characteristics, eliminating the need for different approaches for different cable states, thereby achieving multi-functionality and broad applicability.
3Measurement precision
If an optical fibre is placed inside the electric cable during manufacturing, then conductor temperature can be measured, but the method is invasive and requires cable adaptation
Solution Approach 1:
The patent extracts the temperature sensing function from the internal cable structure and relocates it to the outer surface. By measuring temperature peripherally and using the known thermal resistance of the cable layers to calculate the conductor temperature, the method eliminates the need to embed sensors within the cable during manufacturing.
4Duration of action of stationary object
If an optical fibre is inserted over the entire length of the cable, then continuous temperature monitoring is achieved, but the cost increases significantly
Solution Approach 1:
The patent applies partial action by using only the cable's existing outer layers for thermal measurement purposes, rather than inserting additional materials throughout the entire cable length. This approach achieves continuous monitoring capability through computational methods while avoiding the high costs associated with full-length optical fibre insertion.
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 continuous, non-invasive, and cost-effective monitoring of conductor temperature in installed cables, avoiding the need for invasive modifications or additional components, and allowing for accurate temperature estimation.
Implementation Method 1
at least one temperature sensor placed on an outer surface of said at least one layer of material for measuring a peripheral temperature
Implementation Method 2
said at least one layer having a layer thermal resistance T1
Data Source
AI summary
A determination system (100) for non-invasively determining a temperature of a conductor of an electric cable includes an electric cable (10) with at least one electrical conductor (12) and at least one layer of material (14, 16) surrounding the at least one conductor. The at least one layer having a layer thermal resistance T1. At least one temperature sensor (20) is placed on an outer surface (18) of the at least one layer of material for measuring a peripheral temperature Θb1 on the outer surface of the at least one layer of material. A determination unit (22) is configured to determine a conductor temperature Θcond as a function of the measured peripheral temperature Θb1, the layer thermal resistance T1 and the heat flux Wc generated by the flow of an electrical current in the electrical conductor.