Instrumentation

Instrumentation cabinet for distributed PV sites. Each PV system monitored is equipped with a high-resolution data acquisition system that records electrical and environmental measurements at up to 1-second intervals. Time synchronization and data transmittal are typically provided by an onboard cellular modem.

Typical measurement channels include:

Power meter - ac output
Real energy kWh
Real power kW
Reactive energy VARh
Reactive power VAR
Line voltage V
Environmental
Solar irradiance (plane of array) W/m2
PV module back surface temperature ºC

Below is a photo of a single-module monitoring system. The PV module is at a 30º tilt angle, facing south. A microinverter is used to energize the PV module and provide ac power delivery into the grid (although it is relatively small at about 200 W). A pyranometer is located on the bottom left edge of the PV module to measure plane-of-array solar irradiance. The monitoring box underneath the PV module contains the data logger, power meter, and communication equipment.