Transcript
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Guidelines for IR/EL Outdoor Qualification of PV Systems IEA PVPS Task 13 Workshop Munich, 09 June 2015 Magnus Herz, Ulrike Jahn TÜV Rheinland, Germany
[email protected]
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Outline • Motivation • Content of the Guidelines (6 major chapters)
• Summary
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Why Guidelines ? •
Failure not detected
Improving the image quality Making images more comparable •
Different opinions and recommendations
Harmonizing evaluation methods Classification of visible abnormalities
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Content of the Guidelines 1. Normative references (if available) 2. Overview of different types of IR/EL cameras 3. Requirements for cameras and operation conditions 4. Recommendations for the inspection procedure 5. Recommendations for failure classification, evaluation and reporting 6. Examples of abnormalities
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Normative references •
IEC 62446: Grid connected photovoltaic systems – Minimum requirements for system documentation, commissioning tests and inspection Annex D (informative): PV array infrared camera inspection procedure
•
DIN 54190: Non-destructive testing – Thermographic testing – part 1, 2 and 3
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DIN 54191: Non-destructive testing – Thermographic testing of electric installations
Few standards at the moment, but several Technical Specifications (NWIP of IEC TC82 WG2) with focus on IR and EL are in progress
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Overview of EL and IR cameras • • • •
Technical parameters Output rate Price Handling
Classification of cameras Recommended field of application
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Overview of EL and IR cameras IR Smart phone attachment
Lower class
Medium class
Upper class
single-lens reflex camera modification
Medium class
Medium class
Upper class
EL
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
IR camera requirements Minimum requirements for cameras: • Temperature range (-20°C – 120°C) • Recommended resolution > 320 x 240 pixel • Adjustable emissivity • Maximum measurement error (<3K) • Calibration certificate • User friendly documentation
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Outdoor IR recording procedure Minimum requirements for environmental conditions: • Constant irradiance (cloud coverage) • Minimum irradiance PoA (600 W/m2 - 800 W/m2) • Maximum wind speed (5 m/s – 10 m/s)
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Outdoor IR recording procedure Minimum requirements for procedure: • Distance between camera and test object • View angle α < 60°
α
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Simple classification* • Class 1: No abnormalities • Class 2: Thermal abnormality that may cause a problem in the future and can be compared with sample IR images for further decisions • Class 3: Safety relevant thermal abnormality that causes a direct safety problem. Thus the PV plant must be disconnected and the problem has to be solved immediately. *see Technical Specification “Outdoor Infrared Thermography of Photovoltaic Modules and Plants” (IEC TC82 NWIP)
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Detailed classification* Safety category
Description
A
Failure has no effect on safety.
B(f,e,m)
Failure may cause fire (f) , failure may cause electrical shock (e), failure may cause mechanical danger (m), if a followup failure and/or a second failure occurs.
C(f,e,m)
Failure causes direct safety problem (definition of f,e,m see B).
Power loss category
Description
A
Power loss below detection limit <3%
B
Exponential shaped power loss degradation over time
C
Linear shaped power loss degradation over time
D
Power loss degradation saturates over time
E
Stepwise degradation type over time
F
Special degradation type over time
*see IEA-PVPS Report “Review of Failures of PV Modules” http://www.iea-pvps.org/index.php?id=95
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Sample patterns for IR abnorm.* Pattern
Description
Possible failure Electrical Remarks, reason measurements Chapter
One module warmer than others
Module is open Module normally Check wiring circuited - not fully functional connected to the system
One row (substring) is warmer than other rows in the module
Short circuited (SC) or open sub-string - Bypass diode SC, or - Internal SC
Sub-strings power lost, reduction of Voc
Whole module is short circuited - All bypass diodes SC or - Wrong connection
Module power Check wiring drastically reduced, (almost 6.2.7 all diodes zero) strong shunted reduction of Voc
Single cells are warmer, not any pattern (patchwork pattern) is recognized
Safety
Power
A
System failure
May have burned B(f) spot at the module
const. or E
6.2.7 One diode shunted
*see IEA-PVPS Report “Review of Failures of PV Modules” http://www.iea-pvps.org/index.php?id=95
A when const. ext. SC, or E B(f) when Diodes SC
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Sample patterns for EL abnorm.* Cell pattern in a PV module 6.2.5
Potential induced degradation (PID). PID PV modules can be identified with EL images taken at 1/10 of the rated current in an early stage, before a power loss can be noticed. [Berger13]
A
6.2.2
Repetitive induced cell cracks in the production
B(f)
C
6.2.2
Heavy homogeneous mechanical load. The overall crack pattern in the module looks like a X-crack pattern. The X-crack pattern is visualized in the image by the red lines.
B(f)
C
*see IEA-PVPS Report “Review of Failures of PV Modules” http://www.iea-pvps.org/index.php?id=95
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Examples of abnormalities
Module string is not connected
Short circuited (SC) or open sub-string
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Examples of abnormalities Potential induced degradation (PID)
© Matthias Diehl, pvbuero
© Matthias Diehl, pvbuero
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Summary Guidelines will: •
refer to existing standards & technical specifications
•
give an overview of test equipment
•
determine requirements
•
describe classification and evaluation procedures
•
show examples for best practice in the field
Lead to more qualified assessments of PV systems
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Acknowledgements Contributions from 5 countries: •
David Parlevliet (MU, AUS)
•
Karl Berger (AIT, AUT)
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Guillaume Razongles (INES, FR)
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Marc Köntges (ISFH, DE)
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Marco Paggi (IMT, IT)
Project IEA Task 13 FKZ: 0325786A
Project PVScan FKZ: 0325588D
IEA INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME
Thank you for listening !
