Adding a protective net to the PV module will cause the light and shadow to block the PV module, which will consume part or all of the energy generated by the illuminated PV module and reduce the output power. If there is a shadow on the PV module, it will form a hot spot effect, which will affect the power generation efficiency of the entire PV power plant.
Since qualified PV modules have passed the hockey impact test, it is generally not necessary to install a protective net.