Electrical Device Lifetime Prediction Under Temperature and Harmonic Loads
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Solution Overview
Problem
Current methods for determining the remaining service lifetime of electrical devices are inadequate, leading to unplanned exchanges and increased costs due to failure, as they do not accurately account for temperature-dependent aging factors and harmonic loads.
Innovation Solution
A method using a measurement system with temperature, current, and voltage measurement devices to calculate a temperature-dependent aging factor, considering both linear and exponential aging, and harmonic loads, to determine the reduction in remaining service life of electrical devices connected to a power distribution network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a run to fail strategy is used to extend device operation time, then the total number of exchanges is reduced, but the cost per failure increases significantly due to unplanned exchange expenses
Solution Approach 1:
The system performs preliminary monitoring of temperature and harmonic load conditions to predict remaining service lifetime before actual failure occurs. This allows planning exchanges in advance based on predicted lifetime reduction, transforming unplanned failures into planned maintenance events.
Solution Approach 2:
The system continuously monitors operating conditions (temperature, harmonic loads) and provides feedback on remaining service lifetime. This feedback loop enables dynamic adjustment of maintenance scheduling, allowing operators to plan exchanges optimally based on actual device condition rather than fixed intervals or run-to-fail strategies.
2Device complexity
If temperature dependent aging factors are not considered, then the estimation method is simpler, but the accuracy of remaining service lifetime prediction deteriorates
Solution Approach 1:
The system incorporates temperature dependent aging factors and harmonic load parameters into the lifetime prediction model. By monitoring these specific parameters and their effect on insulation aging, the system achieves accurate lifetime prediction without requiring complex comprehensive monitoring of all possible degradation mechanisms.
3Device complexity
If harmonic load effects are ignored, then the calculation process is simpler, but the prediction of remaining service lifetime becomes inaccurate under non-sinusoidal operating conditions
Solution Approach 1:
The system specifically addresses the local effect of harmonic loads on insulation aging by monitoring harmonic content separately. Instead of requiring complete spectral analysis, the system focuses on measuring and evaluating the specific impact of harmonic currents on temperature rise and aging acceleration, providing accurate predictions for harmonic-prone applications.
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 approach allows for more accurate prediction of remaining service life, reducing the frequency of unplanned exchanges and associated costs by accounting for temperature and harmonic effects, thereby enhancing customer satisfaction and operational efficiency.
Implementation Method 1
measuring a temperature value corresponding to the temperature of the electrical device during the specific time period by using the temperature measurement device
Implementation Method 2
measuring a set of current values corresponding to the current applied to the electrical device by the power distribution network during the specific time period by using the current measurement device
Implementation Method 3
measuring a set of voltage values corresponding to the voltage applied to the electrical device by the power distribution network during the specific time period by using the voltage measurement device
Implementation Method 4
determining a reduced maximum operating temperature of the electrical device on the basis of the amount of harmonic load and the maximum operating temperature
Data Source
Figure 1~2
Figure 3~4B
Figure 5~7
AI summary
The present invention relates to a method of determining a reduction of remaining service lifetime of an electrical device (12) during a specific time period. A measurement system is provided comprising a temperature measurement device (20), a current measurement device and a voltage measurement device. A temperature value, voltage values and current values are measured by using the measurement device. A temperature dependent aging factor is determined based on the temperature value and the reduced maximum operating temperature. The reduction of remaining service life is determined based on the specific time period, and the temperature dependent aging factor. Said temperature measurement device (20) is adapted to measure the ambient temperature outside said electrical device (12) and derive said set of temperature values from said ambient temperature, said set of current values, and said set of voltage values