A solar system needs relative less care in running. However, it is not without need for care. Optimal performance can only be obtained by regular attention to certain aspects and that is solar system monitoring. What parameters should be monitored? We will give you a bit of practical philosophy first.
Have you heard the saying “Proof of the pie is in the eating”? That is true. The most important parameter is the system output in terms of power. This is your return on your investment. Power may be monitored independently or as product of output voltage and current. If this power is less than expected, as per experience, then you need to know other parameters to diagnose the problem. Read more here. Parameters which are normally monitored are:
At the array, DC output
At the inverter, AC output
Reporting and Recording
For small systems, manual observation (and recording) may be sufficient. But for a larger, commercial set up, reporting may be automated through any of the means made possible by technology. The connection can be Wi-Fi, blue tooth, or cable, depending on the distances involved. Automated reporting has the advantage of direct recording into a data logging and analysis system.
One basic consideration is: how does this current value compare with the expected value? That is what raises the alarm. But another consideration is trends. Is the performance falling faster than expected in autumn and not rising fast enough in spring? How fast is the year on year average output varying?
You may possess the most sophisticated monitoring, reporting and analysis equipment. But an alert eye will often note things which none of these intelligent systems will do. It is important for the owner or manager, and indeed all staff to be vigilant. Routine inspections will point out hazards before they fall, particularly things like worn out or damaged cables just about to break, a discolored resistor, a loose terminal, etc. If you can afford, an image with an IR camera will show the thermal map, and help point out any hot spots due to faulty components.
Where possible, it may be useful to have a pyranometer monitoring and recording solar conditions. Correlation of sunlight conditions with the AC output will point any weakening link.