Adaptive Blown Fuse Detection Using Negative Sequence Components
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Solution Overview
Problem
In power supply systems, such as UPS systems, there is no direct measurement available to determine the status of rectifier fuses, making it challenging to ensure safe and reliable operation.
Innovation Solution
A method is introduced to determine if input fuses are blown by generating the negative sequence of input components like voltage or current using existing measurements, comparing it to a threshold, and using an adaptive algorithm to adjust for frequency deviations, allowing for reliable detection without additional measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement devices are added to detect fuse status, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses existing current transformers and voltage measurements to self-determine fuse status through negative sequence component analysis, eliminating the need for additional dedicated measurement devices while maintaining detection accuracy
Solution Approach 2:
The negative sequence component acts as an intermediary indicator that indirectly reveals fuse status by analyzing asymmetrical current patterns, avoiding direct measurement of fuse continuity
2Measurement precision
If additional sensors are installed to measure voltage differences across fuses, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The control module utilizes existing voltage and current measurements from the power system to calculate negative sequence components, making the system self-sufficient for fuse detection without requiring additional voltage sensors across fuse terminals
3Adaptability or versatility
If the detection method is made adaptive to frequency deviations, then adaptability is improved, but calculation complexity increases
Solution Approach 1:
The detection algorithm dynamically adapts to varying input frequencies by continuously analyzing negative sequence components in real-time, allowing the system to maintain accuracy across a wide frequency range without requiring manual calibration or fixed frequency assumptions
Data Source
AI summary
Existing measurements of an input component (such as voltage or current) in a three phase power supply system are decomposed into a negative sequence component. The negative sequence component, which is significantly higher when a rectifier fuse is blown, is compared to a threshold and a determination made that a rectifier fuse is blown when the negative component exceeds the threshold. In an aspect, an adaptive algorithm is used to make the detection work better in the range of the nominal frequency of the input voltage. In an aspect, the negative sequence is determined indirectly from the existing measurements.