Visual inspection of the condition of a PV module can reveal several quality issues which
must be considered. In general, when inspecting a PV module before purchase we should
• The PV module is manufactured as a rigid non-permeable structure, sealed and well-constructed
• No visual cracks are observed in the cell surface
• The cells are interconnected in straight lines and that the interconnections follow
industrially made well-oriented connections
• The cells are all of the same type and colouring
• The junction box is well attached to the back of the module
• The modules are from a new/recent production line
Qualifications and Certificates
Certification and adherence to international standards can ensure quality and reliability for
PV modules. Quality marks and seals are important. Modules that comply and have been
tested at certified institutions according to the requirements set by the following standards
are expected to have long lifetime at high performance:
• IEC 61215: Crystalline silicon terrestrial photovoltaic (PV) modules – Design
qualification and type approval
• IEC 61646: Thin-film terrestrial photovoltaic (PV) modules – Design qualification and
• IEC 61730: Photovoltaic (PV) module safety qualification
• EN 50380: Datasheets and nameplate information for photovoltaic modules
In addition, many manufacturers provide information for additional tests assuring
performance quality against several failures and degradation mechanisms such as:
• Anti Potential Induced Degradation (PID) products
• Protection against Hot Spots
• Ammonia resistance
Potential Induced Degradation (PID) resistance
PID is a new form of degradation caused by leakage currents triggered by high voltage installations and certain climate conditions. It can reduce the power of the module significantly hence it is important to select modules that have been tested for PID and are PID resistant.
Light Induced Degradation (LID) resistance
During the first months of operation most modules experience an initial degradation (power reduction) due to the light exposure. A good PV module will exhibit low or no LID.
The experience of the manufacturer and installer is an important aspect for a quality PV
system. Experience includes both the length of time in the industry and also endorsements
from previous customers.
Quality of Service
The quality of service offered by the manufacturer/installer is an important criterion which
includes ease of contact, initial site survey, first impression of their service, previous
customer endorsements and duration of replacement of modules or inverters.
Training of Technical staff
An important factor that directly affects the quality of the installation is the training of the installer.
The inverter is an important component of the PV system as it is the electronic device that
converts the DC produced power to AC. The main requirements in the selection of the
• reliable operation at both high and low ambient temperature conditions
• high conversion efficiency (both Maximum > 96 % and European Efficiency > 95 %)
• automatic operation, visual display of energy yield and faults
• compliance with national codes.
With the use of a Monitoring System the performance of a PV system can be ensured as
these systems offer plant monitoring, performance display, detection of faults and alerting
. A simple monitoring system can be offered by the inverter itself or can be extended with the
use of an irradiance and temperature sensor in order to correlate the weather conditions to
the performance of the PV system.