Multi-Phase Power System Fault Detection via Cross-Phase Signal Products
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Solution Overview
Problem
Conventional methods for assessing the condition of multi-phase power systems require intensive computation and large memory, and are often unable to detect incipient faults or provide reliable diagnoses, especially under certain conditions, leading to potential electrical or mechanical failures.
Innovation Solution
A method and system that acquire voltage and current signals for each phase of a multi-phase power system, calculate products between voltage and current signals with different phase differences, perform frequency analysis on summed products to identify potential faults, and optionally extract direct current and second harmonic components to determine system unbalance and fault existence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to assess the condition of multi-phase power systems, then comprehensive fault detection is achieved, but intensive computation and large memory are required
Solution Approach 1:
The patent extracts and focuses only on the essential features needed for fault detection by calculating specific products between voltage and current signals with different phase differences. Instead of performing comprehensive analysis of all system parameters, the method selectively computes only the necessary products (e.g., Va×Ib, Vb×Ic, Vc×Ia) that contain fault information, thereby reducing computation while maintaining detection capability
Solution Approach 2:
The assessment method is segmented into distinct computational steps: acquiring voltage and current signals, calculating specific products with different phase relationships, summing these products, and performing frequency analysis. This segmentation allows the system to process information in manageable stages rather than performing intensive comprehensive analysis simultaneously
2Reliability
If conventional methods are used to assess the condition of multi-phase power systems, then system monitoring is performed, but incipient faults with minor effects cannot be diagnosed
Solution Approach 1:
The patent applies asymmetry by calculating products between voltage and current signals with different phase differences rather than symmetric same-phase products. Specifically, it computes products like Va×Ib, Vb×Ic, Vc×Ia where the phase difference is not zero, making the calculation sensitive to subtle imbalances and incipient faults that would be masked in conventional symmetric analysis
Solution Approach 2:
Instead of analyzing voltage and current signals directly as conventional methods do, the patent inverts the approach by analyzing the products of voltage from one phase with current from another phase. This inverted approach (cross-phase product analysis) reveals subtle fault conditions that conventional direct analysis misses
3Reliability
If conventional methods are used to assess the condition of multi-phase power systems, then fault assessment is attempted, but unreliable diagnosis is given under certain conditions
Solution Approach 1:
The patent performs preliminary frequency analysis on the summed products to identify characteristic patterns before making fault diagnoses. By pre-processing the calculated products through frequency analysis and identifying specific frequency components, the system establishes a reliable baseline for comparison that improves diagnosis consistency across varying operating conditions
Data Source
AI summary
A method of assessing a condition of a multi-phase power system comprises the steps of: acquiring a voltage signal and a current signal for each phase of the multi-phase power system; calculating a product of the voltage signal for each phase of the multi-phase power system with one of the current signals such that the product is between a voltage signal for one phase and a current signal for a different phase for at least two of the products; summing the calculated products; and identifying the possible existence of a fault in the multi-phase power system based on a frequency analysis of the summed calculated products.