The testing of the photovoltaic system is necessary periodically, in the face of substitutions of system components, such as photovoltaic modules, inverters, wiring, etc.etc. to ensure the correct operation of the same system. The test is carried out with highly professional instruments and in accordance with the Guide CEI 82-25.

The testing operations mainly consist of: 

1) Visual Inspection
Having acquired the project and verified that the installer has issued the declaration of conformity pursuant to Law 37/08, the visual examination must ascertain:
- that the plant is in conformity with the project, that the modules are installed correctly, that the carpentry is firmly anchored and that all precautions have been taken to avoid water infiltration from the roof;
- that the plant has been built in compliance with the provisions of the Standards in general and of the specific reference Standards for the installed plant;
- that the electrical equipment complies with the relevant standards, is chosen correctly and installed in compliance with the regulatory requirements and that there are no visible damage that could compromise safety;
- that the distance between the barriers and other protective measures has been respected;
- that there are adequate disconnection and interruption devices;
- that there is the identification of the neutral and protection conductors, the identification of the commands and the protections, the connections of the conductors.

2) Cables and conductors verification
For cables and conductors it must be checked that the sizing is done according to the flow rates indicated in the CEI-UNEL tables and that they are equipped with identification marks, where prescribed, and are suitable for the type of installation.
3) Verification of the electrical continuity and of the connections between the photovoltaic modules.
4) Check the grounding of masses and unloaders.
5) Verification of the insulation resistance of the electrical circuits from the masses, checking that the values ​​foreseen by the CEI 64-8 standard are respected

It must be carried out with the use of an appropriate instrument and the measurement is carried out in direct current. The test apparatus must provide the voltage indicated in Table A when supplying a current of 1 mA.

The measurement must be carried out between the system (connecting all active conductors together) and the earth circuit; the measurement of insulation resistance between active conductors is recommended as far as practically possible. During the measurement, the user devices must be switched off. The minimum values ​​allowed are those foreseen by the CEI 64-8 Standard.

7) Technical-functional verification of the plant

The technical-functional verification of a photovoltaic system requires evaluation:

- electrical continuity and connection between modules;

- grounding of masses and unloaders;

- the correct functioning of the photovoltaic system in the different conditions of power generated and in the various modes provided by the conversion group (ignition, shutdown, power failure) etc .;

- insulation of electrical circuits from the masses.

Before performing the technical-functional checks it is advisable to check:

- that there are stable irradiation conditions so as to make the measurements carried out stable;

- that there is a radiation of at least 600 W / m2 aligning the radiation sensor to the plane of the modules;

- that checks are not carried out during the hottest hours;

- that checks are not carried out in the presence of hot days, as the presence of moisture in the air leads to an increase in the widespread component, an increase which in turn leads to a lower yield on the field;

- that the modules are clean

At this point it is possible to proceed with the instrumental testing for the technical verification

At the end of the test procedure, a test certificate must be issued in which all the technical-instrumental tests carried out and the results of the measurements made to verify the conditions set out above will be declared.

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