Specialist Services

RENEWABLE ENERGY SYSTEMS

Servizi
Specialistici

RENEWABLE ENERGY SYSTEMS

Our Engineers and Technicians have such experience, tools and skills to be able to perform specialist analyses such as thermography with RPA (remotely piloted aircraft or drones), UV analysis, I-V and dark I-V curves, electroluminescence, UV fluorescence even in a massive manner and on all the components.

UV Analysis

UV-F analysis (ultraviolet fluorescence) allows for the detection of chromophores (decomposition products) of the encapsulation polymer of glass or back sheet (generally EVA – ethylene vinyl acetate) before they become visible to the naked eye, then to evaluate the aging effects of the encapsulation polymer, the permeability to humidity and oxygen of the module, the presence and historicity of any micro-cell cracks (not visible with thermography), as well as the corrosion of bus bars.

I-V and Dark I-V curves

The measurement and calculation of the I-V curve (current – voltage), of the module or of the string, allows to identify the short-circuit current and the no-load voltage. I-V curves can be performed with sunlight or at night (Dark I-V) by appropriately feeding the strings and therefore independently of the weather conditions, temperature and irradiation.

The detection of the I-V curve and the consequent calculation of the equivalent resistances can give very useful indications to identify problems of:

1) Short circuited bypass diodes
2) Glass corrosion
3) Delamination
4) Module degradation
5) PID (Polarization Induced Degradation)
6) LID (Light Induced Degradation) for Crystalline modules
7) Short circuited cells
8) Broken cells

Outdoor Electroluminescence

Electroluminescence (EL) is photography (in the dark, with a camera equipped with a high-pass filter LWP) of the weak emission caused by the passage of reverse current through the cells of a photovoltaic module.

Until a few years ago, this type of analysis was the prerogative of a few specialized laboratories where the test could only be performed on a limited number of modules that had to be disassembled, packaged and adequately shipped with obvious repercussions in terms of time and costs. Today, our technicians perform EL Outdoor analysis, or directly in the field.

Through the analysis of an EL Outdoor image it is possible to identify all the cell cracks in the photovoltaic modules but also:

1) Defective bypass diodes (or short circuited) inside the junction box of the modules
2) Micro-cell fractures
3) PID (Potential Induced Degradation) of the cells
4) Frontal electrical contact problems of the cells
5) Failure to match cells and/or modules on the system

Thermography

Infrared images are certainly effective for discovering a wide range of defects and damages on the photovoltaic system such as:

  • Hot spots
  • PID (Potential Induced Degradation) of the cells
  • Short circuited bypass diodes
  • Open strings

Nevertheless, manual detection in MW size or multi-MW plants is particularly expensive in terms of time and money, which is why ESAPRO has also specialized in the use of RPA (remotely piloted aircraft or drones), equipped with high resolution radiometric sensors (IR) that allow simultaneous recording during the flight in the visible band and quickly identify the anomalies and defects present which, through the georeferencing of the images, are automatically positioned at the module level.

CASE HISTORY

Description of the intervention

Thermography performed by RPA (Solar Eye) and analysis of the anomalies: 1264 modules were found with Hot Spot problems out of 16,360 modules installed

Power

1.6MWp

Location

Veneto

Description of the intervention

Fluorescence analysis with ultraviolet rays performed: Early ageing of the encapsulate material (EVA) was found.

Power

0.99MWp

Location

Veneto

Description of the intervention

Electroluminescence analysis (EL) was performed: Modules affected by PID (potential induced degradation) were found.

Power

0.99MWp

Location

Veneto

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