Photovoltaic system performance

The primary energy input is the global light irradiance in the plane of the solar arrays, and this in turn is a combination of the direct and the diffuse radiation.

Specifically, there is a need for both electronic monitoring sensors and independent weather sensing (irradiance, temperature and more) in order to normalize PV facility output expectations.

Irradiance sensing is very important for the PV industry and can be classified into two main categories - on-site pyranometers and satellite remote sensing; when onsite pyranometers are not available, regional weather stations are also sometimes utilized, but at lower quality of data; the Industrial IoT-powered sensorless measurement approach has recently evolved as the third option.

A parameter called the 'performance ratio'[3] has been developed to evaluate the total value of PV system losses.

Hence, system performance varies depending on its architecture (direction and tilt of modules), geographic location and the time of day, weather conditions (amount of solar insolation, cloud cover, temperature), and local disturbances such as shading, soiling, state of charge, and system component availability.

[4][5] Many solar PV parks utilize advanced performance monitoring solutions, which are supplied by a variety of technology providers.

In rooftop solar systems it typically takes a longer time to identify a malfunction and send a technician, due to lower availability of sufficient photovoltaic system performance monitoring tools and higher costs of human labor.

A number of technical solutions exist to provide performance measurement and monitoring for solar photovoltaic installations, differing according to data quality, compatibility with irradiance sensors as well as pricing.

An essential part of PV system performance evaluation is the availability and the quality of energy generation data.

For solar PV systems that use microinverters (panel-level DC to AC conversion), module power data is automatically provided.

These data acquisition units connect to the serial links of the inverters, complying with each manufacturer’s protocol.

[8] A parameter called the 'performance ratio'[3] has been developed to evaluate the total value of PV system losses.

Two SR30 pyranometer positioned on a bracket, horizontally and in plane of array, next to a solar panel.
The SR30 pyranometer is an example of an PV monitoring sensor, which can be used in two orientations (horizontal and in plane of array) for measuring irradiance.
Rbee Solar, PV monitoring with solar irradiance measurement
The VU01 pyranometer ventilation unit with SR20, with heater and ventilation, is an A-class compliant pyranometer according to the IEC 61727-1.