The PV plant shows high levels of soiling, as well as hotspots and inactive cell strings caused by the impact of near shading and inconsistencies of the inclination and orientation of the modules. The foundation used for the mounting tables is not robust. It is recommended to (i) conduct a reengineering of the modules and strings with individual MPPT assignments, (ii) double the cleaning frequency, (iii) replace the defect modules, (iv) use gravel that increases the reflective properties of the soil, and (v) relocate some shading objects. The estimated production boost caused by the retrofitting actions lies between 14% and 18%.
Heavy soiling detected even though the visit took place 4 days after a heavy rain and hail storm fell in Delhi.
A significant amount of modules with inactive cell strings were found during the infrared inspection.
Near shadings effects are caused by water tanks and metal structures located in the south part of the system
Soiling measurements were conducted measuring both the short circuit current and nominal power before and after cleaning at irradiations of 600 - 780 W/m2. The estimated soiling loss of the nominal power is in the range of 4%.
Modules with inactive cell strings underperform 33% to 66% depending on the amount of affected strings. The extrapolation of the inspected sample to the whole system leads to a loss of 6% on system level.