For most customers, a solar inverter’s basic display is informative enough. It is easy to access—right on the front of the inverter — and displays the basic monitoring parameters, which typically includes instantaneous power output, daily energy production, and total up-to-date energy production. And this is the kind of monitoring solution that is predominantly seen in most residential and small commercial rooftop solar plants in India.
In large ground-mounted solar plants and commercial & industrial rooftop solar plants, there is a need for a greater degree of control and more depth in monitoring. Remote monitoring options offered with some inverters can provide basic system performance information in a portable device, allowing developers or installers the luxury to view the data anywhere with internet connectivity.
String-level monitoring system
Most often, we see that the monitoring solutions at a solar plant are only at the inverter level. Did you know that such a conventional approach to choosing monitoring solutions makes it difficult in detecting losses at the DC-side?
It is assumed by most customers that the inverter provider takes care of monitoring. After all, there are some useful parameters listed on the inverter monitor from time to time. But the depth of monitoring data that typical inverter-level monitoring provides may not be sufficient.
String-level monitoring, which comes with advanced monitoring capabilities through its’ extensive data acquisition can make a big difference to plant performance in the long-term. A solar plant deployed with a string-level monitoring system gathers inputs from inverters, string combiner boxes, weather station (which comprises pyranometer as well as instruments for measuring cell and ambient temperatures) and net-meter. All these add a high degree of reliability and ensures that under-performance of the plant is mitigated.
Through this advanced monitoring capability, a faulty panel or set of panels can be narrowed down to the string level by identifying the reduced power generation in a particular string. For example, if the fault is reduced to a string of 20 panels, it would be pretty straightforward to detect the faulty panel and replace it, unlike in an inverter-level monitoring system.
Rather than increase the energy yield, it would be appropriate to say that a string-level monitoring system helps reduce the maintenance turnaround time. It detects faults faster than a conventional inverter monitoring system thereby preventing energy generation losses, which effectively results in higher electricity generation.
Of course, the cost factor is high when such superior monitoring capabilities are introduced. But the advanced monitoring capabilities that come with it can help save a lot of money for a solar plant expected to function for 25 years.
What are some of the advanced analytics capabilities offered by IoT-based solar monitoring solution providers?
IoT or ‘Internet of Things’ is a concept that has gained prominence over the past decade and refers to the interaction between physical objects that are equipped with intelligence through computing devices.
Conventional monitoring solutions are not equipped to provide the kind of rigorous analytics, insights, and observations that would be required especially for large solar power plants, whether it be rooftop or ground-mounted.
Currently, there are many state-of-the-art IoT-based solar monitoring solutions offering advanced analytics. They compile, analyze and manage massive quantities of time-series data generated by sensors such as pyranometers, string monitoring units, energy meters, inverter data units, etc.
The data acquired from solar plants is stored in the cloud and can be viewed remotely from any place with an internet connection.
Some IoT-based solar monitoring platforms provide excellent performance analytics through provisions for the following:
- Calculation of performance parameters like Performance Ratio (PR) and Capacity Utilization Factor (CUF)
- Spatiotemporal analysis of generation
- Root cause analysis to evaluate factors that impact energy production
- Offline analysis in case the data has to be downloaded to your system for a much more in-depth analysis
By deploying a superior monitoring solution with string-level monitoring coupled with advanced data acquisition capabilities, the maintenance visits can be reduced to a great extent. The availability of online control, comprehensive reports, and statistics helps reduce expenses and improve overall plant efficiency.