Non-Intrusive PV Module Defect Detection via Light Shielding
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Solution Overview
Problem
Existing photovoltaic power generation inspection techniques face challenges in identifying defective photovoltaic cell modules within a string without disconnecting the system, particularly affecting small- and middle-scale facilities, and struggle to diagnose defects in series-connected structures like large-scale power generation facilities.
Innovation Solution
A photovoltaic power generation inspection system that connects multiple cell strings in parallel, using a current detector to measure output currents without disconnection and a light shielding member to estimate defective modules by observing changes in output currents when modules are sequentially shielded from light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a measurement signal is applied to a photovoltaic cell string by disconnecting it from the system, then the defective position and defective type can be identified, but power loss occurs and work load increases
Solution Approach 1:
A current detector is introduced as an intermediary device to measure the output current of the photovoltaic cell string without requiring disconnection. The current detector acts as a mediator between the photovoltaic cell string and the inspection system, enabling non-intrusive measurement that maintains system operation while providing defect detection capability
Solution Approach 2:
The system utilizes changes in output current parameters as modules are sequentially shielded from light. By monitoring how the output current changes when specific modules are blocked, the system can identify defective modules based on abnormal current variations, eliminating the need for system disconnection
2Reliability
If photovoltaic cell panels are shielded from light to diagnose operational state, then diagnosis can be made regardless of light source state, but individual output detection of each panel is required which is difficult in series-connected structures
Solution Approach 1:
The photovoltaic cell string is segmented into individual modules for sequential inspection. By shielding one module at a time and measuring the corresponding change in total output current, the system can identify which specific module is defective. This segmentation approach allows diagnosis of series-connected structures without requiring individual electrical access to each module
Solution Approach 2:
The system employs feedback by continuously monitoring the output current changes as modules are sequentially shielded. The measured current variations provide feedback information that is analyzed to determine the operational state of each module, enabling reliable diagnosis in series-connected configurations where individual panel output detection would otherwise be complex
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 the identification of defective photovoltaic cell modules within a series-connected string without disconnection, improving inspection accuracy and efficiency by forming a constructive defective state and measuring output current changes, thus reducing power loss and workload.
Implementation Method 1
a photovoltaic power generation inspection system in a photovoltaic power generation system having a structure in which a plurality of photovoltaic cell strings each formed of a plurality of series-connected photovoltaic cell modules are connected in parallel, the photovoltaic power generation inspection system detecting a defective module that is a photovoltaic cell module having a defect among the plurality of photovoltaic cell modules included in a defective string that is a photovoltaic cell string identified as having the defect
Data Source
AI summary
A defective photovoltaic cell module is identified without disconnection in a photovoltaic cell string. As a typical embodiment, in a photovoltaic power generation inspection system in a photovoltaic power generation system having a structure in which a plurality of photovoltaic cell strings are connected in parallel, the photovoltaic power generation system detecting a defective module among a plurality of modules included in a defective string, the photovoltaic power generation inspection system includes: a current detector that measures an output current of a photovoltaic cell string without disconnection; and a monitor unit that estimates a defective module based on change in a plurality of output currents each measured by the current detector while the photovoltaic cell modules included in the defective string are sequentially shielded from light by a light shielding member.