Solar PV Tests

Although a solar panel may seem like a single block, it is made of a number of chemical components and materials, each of which is crucial to effectively and efficiently converting sunlight into usable electricity. Almost all solar photovoltaic (PV) panels use crystalline silicon wafers as the main component material. Silicon is used to create semiconductors in about 95 percent of all solar panels on the market today.

Unlike many other electrical systems, the direct current side of photovoltaic panels is not always turned off to allow electrical testing. In any case, certain electrical tests require that irradiance data, ie solar energy per unit area, be evaluated as part of the test procedure.

Visual inspection helps ensure that there are no problems with the photovoltaic system, such as damage to modules, cable connectors, cables or other PV components such as inverters or combiner boxes. Visual inspection is carried out not only during commissioning, but also during periodic tests.

Generally, tests of a photovoltaic system fall into two categories: system test and measurement and system performance test.

In system testing and measurement, the direct current side of a photovoltaic system is tested and generally includes:

• Continuity testing or resistance testing is performed to verify the integrity of protective earthing, earthing or equipotential bonding conductors and connections. The system must be properly grounded to reduce the risk of electric shock to personnel.
• Polarity testing is required to ensure correct connection to other components in the system, such as inverters, charge controllers or batteries, where cross-polarity causes minimal loss of efficiency, but is extremely dangerous at worst.
• Voltage and current testing is performed to verify that the photovoltaic system is operating within its design specifications. Open-circuit voltage and short-circuit current are often used to verify these characteristics.
• Insulation resistance testing is used to identify faults in insulation by testing the integrity of wiring and equipment.
• Functional testing ensures that parts such as switchgear and other control devices are correctly assembled, connected and functioning.

Performance testing of photovoltaic systems is necessary to ensure that the photovoltaic system is working according to the system design. This usually includes voltage and current measurements and IV curve (current-voltage curve) tracing. Comparison should be made with standard test conditions that take into account temperature, radiation and spectral data and, when combined with electrical measurements, are used to verify the power and energy of the photovoltaic system and allow comparison with the manufacturer's specifications.

From another point of view, the absolute minimum tests that must be performed during the installation of a solar photovoltaic system are: continuity measurements, open circuit voltage, short circuit current and insulation and irradiance.

Other tests involving the use of IV curve trackers, power analyzers and thermal imaging cameras are considered useful, although not mandatory, to perform certain diagnostic tests or to evaluate different performance parameters of a solar photovoltaic system.

Companies that manufacture photovoltaic systems use standard test conditions to rate these products. Standard test conditions are 1.000 Watts of solar radiation per square meter, 25 degrees C cell temperature, air mass equal to 1,5, and ASTM G173-03 standard spectrum.

According to the "ASTM G173-03(2020) Standard tables for reference solar spectral irradiance: Direct normal and hemisphere at 37 degrees inclined surface" developed by the American Testing and Materials Organization (ASTM), the absorption, reflection and transmission of solar energy are important factors in material degradation studies, solar energy system performance, solar photovoltaic system performance, biological studies and solar simulation activities.

Solar PV tests are among the numerous tests, measurements, analysis and evaluation studies given to businesses by our organization.