• • Shading-type hot spots exhibit |ksc| increases of 402.6–736.8% and |koc| reductions of 1.9–20.9% relative to normal modules (|ksc|=0.0038, |koc|=1.6873), with Icutoff dropping from 7.61 A to 6.57 A. This signature enables rapid field identification of shading faults, reducing troubleshooting time by approximately 40% compared to conventional thermal imaging alone.
• • Crystal defect-type hot spots show |ksc| increases of 1044.7–2884.2% and |koc| decreases of 4.2–20.1%, with Icutoff declining from 7.43 A to 7.09 A. The extreme sensitivity of |ksc| to defect density provides an early indicator of metallurgical contamination, allowing intervention before power loss exceeds 25%.
• • Microcrack-type hot spots are distinguished by |ksc| increases of 873.7–1852.6% and |koc| reductions of 27.6–44.2%, with Icutoff falling from 7.86 A to 7.52 A. The pronounced |koc| drop correlates with increased series resistance, offering a quantitative metric for crack severity assessment and prioritization of module replacement.
• • The study establishes that power loss (Ploss) alone is insufficient for fault classification; combining |ksc|, |koc|, and Icutoff yields a three-parameter diagnostic matrix that achieves preliminary discrimination among shading, crystal defect, and microcrack hot spots, as well as between microcracks and microcrack-induced hot spots, with potential to reduce misdiagnosis rates in O&M workflows.