Table 2 Root cause analysis of hotspots in pv panels
From: Techniques of infrared thermography for condition monitoring of electrical power equipment
Type of Fault | Parts/location | Process | Activity | Cause of hotspot fault |
|---|---|---|---|---|
Cracking | Protective Glass & Active solar cells | Production, packaging, transport, Installation | Mismatch of bolts, poor tightening, External force, falling objects[58] | Water penetration, create shading[59] |
Poor Interconnection (series & parallel cells or panels)[60] | Conducting portions | Production, packaging, transport, and Installation [61] | Mechanical stress, Imperfect solders | High resistance of junction conductor |
Corrosion [62]- increased humidity in modules causes corrosion | Delamination, cracks, and encapsulation [63] | Moisture penetrates modules via the edge of the module frame | Reduce conductivity, cause leakage currents | Reduce power produced, high resistance, hotspots |
Bypass Diode Fault | String (series of cells) shadowed by object | String output voltage less than adjacent strings | The reverse bias of shaded string due to current flow from good to bad string | A bad bypass diode not blocking the reverse bias current flow [64]. Heating in PV module hotspots |
Shading, Soiling (External Factors) | Dark (100% cover) [65]/transparent shading (< 100% cover [66]. (home, tree/smoke, fog, dried liquid film, and bird droppings) | trigger moss on the surface of PV panels | Bad bypass diode not blocking the reverse bias current flow | Heating in PV module hotspots |