What is a Hotspot in a P.V array?
The Interconnected modules in the Solar PV Array must be electrically matched.
The strings must generate the same voltage when connected in parallel and the same current when connected in series.
- A mismatched module will result in a relatively high reverse current
- This current can flow through the damaged or shaded cell creating a hotspot.
- The module or cell will now act as an internal load
- This Effect will cause the array to dissipate power and reduce the efficiency of the array.
Results of a Hotspot
The high temperatures from a hotspot can degrade the PV material which will reduce the performance and operating life of the PV array.
Blocking Diodes installed within the module will not allow reverse currents to flow, and will protect the module from a hotspot.
What is a Mismatch?
The term of mismatch refers to the interconnection of solar cells or modules, which do not have the same identical properties.
In fact, different modules which have a different condition of each other can cause a mismatch in the PV array.
The Peak power output of a module is determined by the cell with the lowest output If a cell of a module is shaded the power being generated by the other cells will be limited by the lower performance of the shaded cell (module).
The current on the module will be limited to the current to the mismatched cell. In fact, it reduces the Current and the Voltage which can reduce the PV panel performance dramatically.
A Mismatch also can occur from a damaged P.V cell.
See a Solar PV Module Mismatch example in the P.V array output below
SaveMemoney Recommend SolarEdge Module Level Optimized Solar PV Systems, which can handle the Mismatch of the PV Panels and because of this can reduce the chance of a hotspot development in your Solar PV Array!