Arc Energy Evaluation in Photovoltaic Installations
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Solution Overview
Problem
Photovoltaic installations face challenges in detecting and managing electric arcs, which can lead to destructive fires due to the lack of natural arc quenching in DC systems, and existing detection methods often result in unwanted shutdowns or fail to accurately assess the energy released by arcs.
Innovation Solution
A method and device that measure current signals at high frequencies to evaluate the energy produced by electric arcs by determining initial and arc current values, calculating arc voltage, and integrating these values over time to assess energy release, with a device comprising modules for signal processing and energy calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sampling frequency current measurement is used to evaluate arc energy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential information needed for arc energy evaluation from the high-frequency current signal. By identifying and measuring only the voltage jump magnitude and duration characteristics, the system avoids processing the entire high-frequency signal, thereby reducing computational complexity while maintaining measurement precision.
Solution Approach 2:
The patent applies partial action by using high sampling frequency only during arc detection events rather than continuously. The system switches to high-frequency measurement mode when an arc is detected, and returns to normal operation otherwise, reducing overall device complexity while achieving precise arc energy measurement when needed.
2Reliability
If arc detection is performed to prevent fires, then safety is improved, but productivity decreases due to unwanted shutdowns
Solution Approach 1:
The patent changes the detection parameter from simple arc presence detection to arc energy evaluation. By calculating the integral of voltage jump magnitudes over time, the system distinguishes between harmful arcs exceeding energy thresholds and benign arcs during normal operations, enabling selective intervention that maintains safety while avoiding unnecessary shutdowns.
Solution Approach 2:
The patent implements feedback by continuously monitoring arc energy levels and comparing them against predetermined thresholds. The system only triggers shutdown actions when the evaluated arc energy exceeds the threshold, providing intelligent feedback-based control that prevents false positives and maintains installation availability while ensuring safety.
3Device complexity
If simple arc detection methods are used, then device complexity is reduced, but measurement precision of arc energy is insufficient
Solution Approach 1:
The patent introduces an intermediary calculation step that integrates voltage jump magnitudes over time to evaluate total arc energy. This intermediary energy evaluation metric bridges the gap between simple detection and precise measurement, allowing the use of relatively simple detection devices while achieving accurate arc energy assessment through the integration process.
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
Effectively evaluates the energy released by electric arcs, enabling timely intervention to prevent damage and fires by accurately assessing arc energy and triggering protective measures when thresholds are exceeded.
Implementation Method 1
Measuring an electric current signal produced by the installation at a sampling frequency greater than or equal to 50 kHz
Implementation Method 2
The plasma of the electric arc performs the role of a resistance that increases over time. The initial voltage edge is therefore generally followed by a gradual increase in the arc voltage, which may continue until it reaches an open circuit voltage
Implementation Method 3
An electric arc may occur in the event of a conductor fault or in the event of a faulty connection. It is formed by a plasma that appears between two electrodes
Data Source
AI summary
The invention relates to a method including the steps of measuring (EO) an electric current signal produced by the apparatus (100) at a sampling rate no lower than 50 kHz, and, from the measured current signal, determining (E3) an initial value (10) of the current before the occurrence of an electric arc, determining (E5) current values (Iarcj) during the electric arc, evaluating (E6) arc voltage values from the current values determined during the arc and from the initial value of the current, integrating (E7) over time the product of the arc voltage values evaluated by the determined current values, in order to determine the energy of the arc.