Why PV Power Stations Need Weather Stations: Irradiance, Module Temperature and Wind Configuration

Changes in the generation capacity of photovoltaic power plants can only be distinguished from "normal fluctuations caused by weather" and "abnormalities caused by components, inverters or operation and maintenance" when combined with on-site environmental data. Therefore, the weather station is the data baseline for performance evaluation.

Most critical parameter: irradiance

The GHI represents the total irradiance of the horizontal plane, and the POA/GTI represents the irradiance on the inclined plane of the component. For the actual power generation performance of components, POA is generally more direct than GHI alone; large or scientific projects may also add DNI, Dhi, and solar tracking measurements.

Why the component temperature must be measured

When the temperature of the photovoltaic module rises, the conversion efficiency usually decreases. The patch temperature sensor is mounted on the backplane of the component and can distinguish between changes in radiation and changes in power caused by temperature rise.

Effects of Wind, Ambient Temperature and Humidity, and Rain

Wind affects component convection heat dissipation; ambient temperature determines thermal environmental baseline; humidity and rainfall are related to ash cleaning, condensation, and environmental conditions. Large power plants may also be equipped with fouling sensors to quantify soiling loss.

System Integration

The sensor data is synchronized with the SCADA or cloud platform through the data collector, and the time stamp must be consistent with the inverter/meter data for PR, performance analysis, and troubleshooting.

NiuBoL PV Monitoring Portfolio

The NiuBoL PV monitoring solution can combine solar radiation, wind speed and direction, air temperature and humidity, air pressure, rainfall, and component temperature, and connect to a third-party SCADA or cloud platform through RS485 and data acquisition equipment. The irradiance measurement can be referenced to the NiuBoL Pyranometer for Solar PV.

FAQ

Q1: Is it enough for a photovoltaic station to have only one total radiometer?

A1: Small projects can meet the basic reference; performance evaluation should also generally take into account component inclined surface irradiation and component temperature.

Q2: Can an illumination sensor replace a radiometer?

A2: It cannot be used for rigorous PV performance analysis because Lux is weighted by the visual response of the human eye.

Q3: Why is time synchronization of meteorological data important?

A3: If the irradiance and power data are temporally misaligned, PR and fault analysis will produce erroneous conclusions.