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Solar PV system maintenance in accordance with the IEC 62446-1 standard

Proper maintenance is required for the safe and reliable operation of long-term solar power generation systems, so performing electrical testing on the system in accordance with international standard is important. This article discusses the DC side testing of the IEC 62446-1 standard.
About IEC 62446-1
The IEC 62446-1 is an international standard for testing, documenting, and maintaining grid-connected photovoltaic systems. It sets standards for how system designers and installers of grid-connected PV systems must provide information and documentation to customers. This standard also describes DC testing of the PV system which can be used for periodic testing of the system.
In the standard, the test is classified into categories 1 and 2 according to the size of the PV system. Category 1 refers to all solar PV generation systems, whereas Category 2 refers to larger or more complicated systems such as mega solar power plants.

 

Small-scale PV power generation system Mega-solar power plant

 

Category 1 Inspection

 

Inspection items Earth protective continuity test and/or equipotential bonding conductor Description If the DC side has earthing, such as a frame or equipotential bonding, a continuity test is required. Measuring Instruments Digital Multimeter Insulation Tester * *Ω function

 

Polarity inspection Check the polarity of the cables before connecting them to the switching device or inverter. Digital Multimeter Clamp Meter

 

Combiner box test A test to verify that all strings are connected correctly. Digital Multimeter Clamp Meter

 

Strings open circuit voltage test For checking the voltage of PV modules connected in series. Digital Multimeter Clamp Meter

 

String circuit current test (short circuit or operational) To confirm the function of strings and that there are no major issues AC/DC Clamp Meter Bypass Diode Tester

 

Functional test Check the operation and installation of control devices such as relay switches and circuit breakers. -

 

Insulation resistance test Test the insulation resistance to ensure electrical safety. Insulation Tester

 

All Category 1 tests must be completed and passed before moving on to the additional Category 2 tests. Category 2 Inspection

 

Inspection items I-V curve test Description This test evaluates the current-voltage characteristics of PV strings. Measuring Instruments I-V curve tracer

 

Infrared thermographic inspection The heat generation of PV modules is inspected by the IR thermal camera. By knowing the deviation of the temperature, problems like the bypass diode in the PV arrays can be detected. Infrared Thermal Camera

 

Additional inspections are also available for inspections outside Category 1 and Category 2. Additional test

 

Inspection items Voltage to Ground-Resistive Ground System Description Measure the resistivity according to the technical documentation provided by PV module manufacturer. Measuring Instruments Loop Impedance Meter

 

Blocking diode test This is required for the system using a blocking diode. Check for diode connections and signs of overheating. Digital Multimeter Clamp Meter

 

Wet insulation test To validate that the PV modules are safe when exposed to rain or dew, an insulation resistance test is done with the PV modules in a wet state. Insulation Tester

 

Shade evaluation This is to record the effect of shading by obstacles. -

 

Conclusion Using the right measuring tools is important for keeping the system running and making sure it is safe. At HIOKI, we offer a variety of measuring instruments to ensure the safety and efficiency of measurements for our users.