Series Arc Detection in Photovoltaic Modules Using Voltage Variation
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Solution Overview
Problem
Existing solutions for detecting electric arcs in photovoltaic installations are not rapid, reliable, or cost-effective, often requiring complex and expensive processing due to high-frequency signatures, leading to potential fires and system damage.
Innovation Solution
A method and device for detecting series arcs in photovoltaic systems operating in direct current, which involves measuring the temporal evolution of voltage between stable zones, identifying voltage variations within specific ranges and rise times, and using filtering techniques to isolate the arc signature from noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic detection or radiofrequency detection is used to detect electric arcs, then detection capability is improved, but device complexity and cost increase due to heavy software processing and high sampling requirements
Solution Approach 1:
The patent extracts only the essential voltage variation characteristics (amplitude and rise time) needed for arc detection, discarding the complex high-frequency signature analysis. This selective extraction of critical parameters simplifies the detection system while maintaining arc detection capability.
Solution Approach 2:
The patent replaces expensive, complex processing systems with simple, low-cost voltage measurement circuits and basic comparison logic. The solution uses inexpensive components that perform sufficient detection without requiring heavy software processing or high-end hardware.
2Measurement precision
If complex signature analysis with high sampling is used, then detection precision is improved, but processing time increases to several seconds or minutes
Solution Approach 1:
The patent pre-establishes the critical voltage variation thresholds (0.2V to 20V amplitude and 0.5μs to 5μs rise time) based on arc characteristics. By preparing these reference values in advance, the system can perform rapid real-time comparison without requiring complex post-acquisition processing, achieving both precision and speed.
Solution Approach 2:
The patent measures only the essential voltage variation parameters (amplitude and rise time) rather than performing complete high-frequency signature analysis. This partial measurement approach captures sufficient information for reliable arc detection while dramatically reducing processing time to microseconds.
3Reliability
If high-frequency signature measurement is used, then arc detection accuracy is improved, but cost increases due to expensive components
Solution Approach 1:
The patent replaces complex electronic measurement systems (ultrasonic sensors, RF detectors, infrared cameras) with simple voltage measurement circuits. This substitution uses basic electrical measurement principles instead of sophisticated physical sensing methods, dramatically reducing component costs while maintaining detection accuracy.
Solution Approach 2:
The patent changes the measurement parameter from high-frequency voltage signature to low-frequency voltage variation (amplitude and rise time). This parameter transformation allows the use of inexpensive measurement circuits that operate at lower frequencies, reducing hardware costs while preserving arc detection capability.
Data Source
Figure 1A~1C
Figure 2
Figure 3~5
AI summary
The invention relates to a method for detecting a series arc in a photovoltaic device operating with direct current, comprising N (N=1 or N>1) photovoltaic modules (100, 1, 2, 3) connected to a charging device (10) having a capacitive behavior for the modules, said method comprising: a) detecting, at the terminals of n modules from among the N modules (1≤n≤N), the change in the voltage over time; b) identifying a variation in voltage between a first area (A) having a stable voltage and a second area (B) having a stable voltage, for a duration of at least 5 µs that immediately follows said variation in voltage; and c) determining whether or not the variation in voltage is between a value Vmin that is greater than or equal to 0.2 V and a value Vmax that is less than or equal to 20 V, and a rise time for said variation is between a duration Tmin greater than or equal to 0.5 µs and a duration Tmax that is less than or equal to 5 µs.