SOLAR POWER PLANT SITE TESTS
Compulsory and optional tests Category-1 and Category-2 within the scope of IEC 62446.
Continuity of Earthing Test
Measurements of Voc and Isc
Insulation Resistance Test
Thermal Camera Control of All Boards
Control of PV Modules with Thermal Camera
I-V Curve Measurement for PV Modules and Strings
CONTINUITY OF EARTHING TEST
Where protective grounding and / or equipotential bonding is connected on the DC side, electrical continuity tests shall be carried out on all these conductors and the correct connection
of the main ground terminal shall also be checked.
Grounding is of great importance in all electrical installations, especially in solar power plants. Grounding is of great importance both in leakage current protection and in general protection especially in lightning in the power plant. A disconnection in grounding and co-potentials can cause serious damage to the system. In this context, the megger grounding measurement of the equipotential busbar should be recorded by carrying out earthing measurements of both the construction and the solar panels and the necessary measures should be taken in case the problem is detected.
Before carrying out other tests, switching off the switch or connecting a series of overcurrent protection devices, it is
important to check the safety and polarity to protect the connected equipment from damage.
If control has already been made on a connected system and an inverse polarity is found on an array, by-pass diodes and modules must be checked for any damage caused by this error.
MEASUREMENTS OF Voc - Isc
The purpose of the open circuit voltage (Voc) measurement is to check that the module strings are connected correctly and that the expected number of modules are connected in series.
Bypassing an interconnection or accidentally connecting an incorrect number of modules in a series is a relatively common fault, especially in large systems, and the open circuit voltage quickly detects these errors.
The purpose of the short circuit current (Isc) measurement is to ensure the correct operating characteristics of the system and to verify that there is no major error in PV array wiring. Two test methods are available (short circuit test and run test) and both provide information on the correct operation of PV arrays. Whenever possible, short circuit testing is preferred since the effects from the inverters are excluded.
The switchgear and other control devices shall be tested to ensure that they are correctly installed and connected and that they operate properly.
INSULATION RESISTANCE TEST
Solar panels are subjected to a voltage of 1.000V and the insulation resistance between Panel-Ground is examined. This is important in order not to have any leakage on the panels and not
to cause any harm to the people and also to prevent the inverters from being switched off. The damage caused by the EPC companies during the wiring process is also determined at this stage
and is very important during the commissioning process.
The detection of hot spots is very important in preventing loss of energy production. It is aimed to ensure the highest level of energy production performance by fast and reliable
error detection during the inspections performed with thermal imager. In addition to AC and DC panels, cable and connector connections, hot spots in photovoltaic modules can be
determined by this method.
As a result of thermal inspection, you may be informed about the following subjects.;
Short circuited bypass diodes, J-Box
Problems due to assembly error
Temperature differences in cables, collection boards, connection points, inverters and power units
I-V CURVE MEASUREMENTS
LID, PID, micro-crack, degredation etc. for photovoltaic modules and module arrays thanks to I-V (current-voltage) measurements. problems can be detected. I-V graph measurements for photovoltaic modules and module arrays provide the following information.
Measurements of string open circuit voltage (Voc) and short circuit current (Isc)
Measurements of max power voltage (Vmpp), current (Impp), and max power (Pmax)
Measurement of Array Performance
Measurement of Module / String Fill Factor
Identification of Module / Array Defects or Shading Issues
Problems caused by pollution on the module
LID (Light induced degredation)
PID (Potential induced degredation)
Short circuited bypass diodes
Possible faulty connections in panel series
ELECTROLUMINESCENE (E.L.) IMAGING TEST
Electroluminescence inspection is a method that informs us about cyristal structure of cells that constitute PV modules with analysing of infrared wawelength light emitted by modules with back fedding of electric current.
Thanks to this method, micro cracks on PV modules, manufacturing defects (soldering defects, ohmic contacts etc.), faults accured during assembling and non-operating parts of modules can be detected.
If the photovoltaic modules are not transported and assembled properly, then structural defects occur in the cells. Detecting these defects in the laboratory environment is very laborious and costly, so it is more appropriate to detect them at the plant site.
Proerk Engineering provides electroluminescence testing services both in the factory environment and at the plant site with the electroluminescence units developed as a result of R & D studies.
Please contact us for price information and details.