hotspots

Scientists in Indonesia have investigated early operational defects in a 24.9 MW solar PV system in Sumatra and have identified hotspot formation as the dominant defect. They also detected 282 cases of glass cracking, 350 cases of junction box failures and shading effects linked to module defects.

Scientists in Spain tested PV modules under partial shading conditions, aiming to better understand the formation of performance-damaging hotspots. The study reveals a potential issue particularly affecting half-cell and bifacial modules, which may cause accelerated performance loss and is not covered by current testing/certification standards.

UK researchers have found that crack percentages of up to 11% have a very limited impact on solar cell performance. They also ascertained that hotspots are likely to arise when the crack percentage is in the range of 11 to 34%.

Scientists in the UK investigated the relationship between two of the most worrisome defects that can affect solar cells in the field – cracking and hotspots. Their work analyzed solar cells with different levels of cracking under varying light conditions, finding that the most severely cracked cells were considerably more likely to run at high temperatures and form damaging hotspots.

Scientists at Germany’s Fraunhofer Insititute for Solar Energy Systems (ISE) evaluated the performance of its newly introduced ‘Matrix’ approach to interconnecting shingled solar cells. The institute finds that, thanks to optimized current flows, energy yield of the Matrix approach could almost double that of standard shingled cell interconnection under random shading conditions.

The performance ratio of an installation is stable, yet the yield and the revenues drop significantly. A U.K. case study shows that faults can compensate for performance ratio value, meaning this value is not always a good key performance indicator on its own. This issue will be discussed during the upcoming asset management session at the pv magazine virtual roundtable Europe 2020.