Parallel Arc Detection in PV Installations via Voltage Variation
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Solution Overview
Problem
Existing methods for detecting parallel electric arcs in photovoltaic installations are inefficient due to high costs, complex processing requirements, and incompatibility with direct current systems, failing to provide rapid and reliable detection.
Innovation Solution
A method and device that detect the evolution of voltage over time at the main terminals of a photovoltaic device, identifying a negative voltage variation with specific slope and duration characteristics, and determine if the voltage variation falls within defined thresholds, using passive and active filtering to isolate the signature of a parallel arc.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic detection or radiofrequency detection is used to detect parallel 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 duration) needed for arc detection, discarding the complex RF and ultrasonic signal processing. By focusing solely on voltage measurements and their temporal evolution, the system achieves reliable arc detection without requiring heavy software processing or high sampling rates, thus reducing device complexity while maintaining detection capability.
2Measurement precision
If high sampling rate processing is used to analyze arc signatures, then measurement precision is improved, but processing time increases to several seconds or minutes
Solution Approach 1:
The patent applies partial action by measuring only the critical parameters (voltage amplitude and duration) rather than performing complete spectrum analysis of the arc signature. This selective measurement approach provides sufficient precision for reliable arc detection while reducing processing time from seconds or minutes to near-real-time operation, as the system only needs to detect voltage drops below a threshold for a specific duration.
3Reliability
If series arc detection methods are used in photovoltaic systems, then detection capability is improved, but applicability worsens because these methods cannot detect parallel arcs at main terminals
Solution Approach 1:
The patent changes the detection parameter from current-based (used in series arc detection) to voltage-based measurement. By monitoring voltage variations at the main terminals and analyzing their temporal characteristics (amplitude and duration), the system becomes adaptable to detecting parallel arcs, which manifest as voltage drops rather than current anomalies. This parameter change enables the detection method to be specifically suited for parallel arc detection at PV installation terminals.
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
Enables quick and simple detection of parallel electric arcs, reducing the risk of damage by identifying voltage variations between 100 V and 30 V with a fall time between 0.01 μs and 10 μs, effectively addressing the limitations of existing technologies.
Implementation Method 1
the consequence of such a phenomenon can be, in the worst case, a fire that can lead to the destruction of the building in which a PV module is installed. A parallel arc is established between points or areas at different potentials.
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3~5
AI summary
A method is described for detecting a parallel arc in a photovoltaic device, comprising N (N=1 or N>1) photovoltaic modules, connected to a charge device (10) having a capacitive behaviour for the modules, this method comprising: a) detecting, across the main terminals of said device, the evolution of the voltage over time, at least during the formation of the electric arc, b) identifying a negative voltage variation between a first zone (RI) with stable voltage and a second zone (R2) with stable voltage for a period of at least 5 μs, which immediately follows said voltage variation, and c) determining whether the voltage variation is comprised between a maximum value Vmax, greater than or equal to 100 V, and a minimum valve Vmin, less than or equal to 30 V, with a lowering time of that variation comprised between a minimum duration Tmin greater than or equal to 0.01 μs and a maximum duration Tmax less than or equal to 10 μs.