Simulation of Poa Irradiance Sensor Placement Biases in Single-axis Trackers: a Mid-latitude Case Study With Open-source Tool
Abstract
This study evaluates the bias introduced by plane-of-array (POA) irradiance sensor placement in single-axis tracking photovoltaic (PV) systems, with particular attention to edge effects within utility-scale tracker rows. Using the bifacial_radiance simulation tool, two sensor placement configurations were analyzed for a site in Sorocaba, Brazil. In Simulation A, a sensor was placed at the northern edge of an edge tracker, representing a worst-case placement scenario. In Simulation B, a sensor was positioned near the midpoint of a centrally located tracker, aligning with industry best practices. To establish a reference irradiance for Simulation B, hourly POA distributions from 20 virtual sensors across the central module were evaluated over a complete meteorological year. Annual results revealed that the edge-mounted sensor in Simulation A overestimated POA irradiance by 2.2% relative to the centroid-derived reference from Simulation B.
Keywords
Ray-tracing simulation, Edge effects, Single-axis trackers, POA irradiance.