Photovoltaic Arc Detection Using Windowed Voltage Analysis
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Solution Overview
Problem
Current methods for detecting electric arcs in photovoltaic systems are either complex and expensive or insufficient in distinguishing between arcs and other voltage increases, posing a safety risk due to the high direct voltage operations and integration risks with building structures.
Innovation Solution
A method that measures voltage values in a photovoltaic installation, digitizes them, forms a window of recent data, calculates a test value based on voltage measurements, and analyzes a test vector to determine the presence of an electric arc using simple calculations and inexpensive hardware, allowing for real-time detection and differentiation between series and parallel arcs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic wave analysis is used to detect electric arcs, then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex ultrasonic wave analysis with a simplified electrical measurement system. Instead of using ultrasonic sensors and complex signal processing, the invention uses voltage measurement across the component with arc detection based on analyzing voltage characteristics during switching operations. This substitutes a mechanical/acoustic detection system with an electrical measurement system, reducing device complexity while maintaining detection capability.
Solution Approach 2:
The patent extracts only the essential voltage measurement aspect from the complex ultrasonic detection method. By focusing solely on voltage characteristics during switching operations and removing unnecessary complexity, the invention achieves arc detection with a simplified system that measures only electrical parameters rather than requiring comprehensive ultrasonic analysis.
2Device complexity
If simple voltage measurement is used to detect electric arcs, then device cost is reduced, but ability to distinguish arcs from other voltage increases deteriorates
Solution Approach 1:
The patent applies dynamics by analyzing voltage measurements specifically during the dynamic switching operation of power electronic components. Instead of continuous monitoring, the system captures voltage characteristics during the transient switching phase when arcs are most likely to occur. This dynamic measurement approach enables accurate arc detection using simple voltage measurement, distinguishing arcs from other voltage variations through timing and characteristic analysis.
Solution Approach 2:
The system uses feedback by comparing measured voltage characteristics during switching with expected normal switching patterns. When voltage deviations exceed thresholds or exhibit arc-specific characteristics during the switching event, the system triggers an alarm. This feedback mechanism enables simple voltage measurement to achieve precise arc detection by continuously comparing actual measurements against reference patterns.
3Reliability
If continuous ultrasonic signature analysis is performed, then detection reliability is improved, but processing time and computational requirements increase
Solution Approach 1:
The patent uses periodic action by measuring voltage only during specific switching events rather than continuous monitoring. The system triggers measurements at predetermined intervals corresponding to switching operations, analyzing voltage characteristics only during these periodic events when arcs are most likely to occur. This reduces processing time significantly compared to continuous analysis while maintaining detection reliability through targeted periodic measurements.
Data Source
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AI summary
The invention relates to a method for detecting an electric arc in a photovoltaic facility, including the following steps: measuring (E6) voltage values at at least one location of the electric circuit of the photovoltaic facility; digitizing (E8) the measured voltage values in order to produce voltage data; forming (E11) a window of n recently digitized voltage data; calculating (E12) a test value associated with said window of n voltage data; analyzing (E13) a test vector that includes m test values associated with m recent windows generating a quantity originating from this analysis, which is representative of an electric arc risk; and comparing (E15) said resulting quantity with at least one threshold in order to derive therefrom the presence or absence of an electric arc within a photovoltaic facility.