Site I.5

Health
COD
2016
Nominal Capacity
125 kWp
Yield since COD
1204 kWh/kWp
Possible Gain
5% to 10%
CAPEX, OPEX
1.8 ₹/Wp, 0.6 ₹/Wp/a

Abstract

The PV plant shows significant soiling caused by bird droppings, inconsistencies of the module orientation, disconnected cables at the inverter input, a significant amount of inactive cell strings and mutual shading between the subsystems. The modules are also affected by product defects. It is recommended to (i) increase the cleaning frequency to at least twice per month (ii) replace defect modules, (iii) rearrange the strings based on shading categories, and (iv) check all inverter cable connections. The estimated production boost caused by the retrofitting actions lies between 6% and 10%.

Image gallery

Main Findings

Heavy soiling caused by bird droppings has been detected. A large amount of birds gather on the rooftop system every day.
The PV tables have multiple orientations and tilts lacking homogeneity. The Adani modules in the third system were shaded by the system containing the Medors modules.
The system containing JJ modules showed a significant amount of snail trails, multicracks, hotspots and broken junction boxes.
The system containing Medors modules showed hotspots as well as a significant amount of inactive cells strings.
The infrared analysis showed hot junctions at the DC cable entry. In some inverters disconnected cables were found.
The irradiation sensor was improperly installed and soiled.

Impact on Performance

Cell Cracks

Based on the crack distribution and type found during the electroluminescense inspection, is it likely that the module’s nominal power has been reduced by approximately 4%. Furthermore, these types of cracks could eventually lead to inactive areas and higher power loss in the midterm.

Estimated Loss
≈ 4%
Disconnected circuits

The string cables disconnected from the inverter had an impact of 7% on the overall installed capacity at the time of the visit.

Estimated Loss
≈ 7%
Inactive Cell Strings

The short circuited modules and the modules with inactive cell strings lead to an overall reduction of the nominal power of around 3%. This statement bases on the extrapolation of the results of the inspected samples.

Estimated Loss
≈ 3%
Total Estimated Energy Loss
≈ 14%

Proposed Solutions

The irradiation sensor should be properly reinstalled in order to ensure an accurate PR calculation.
Spikes against birds shall be installed at the upper edge of the modules.
The beam from the mounting structure on the west side of the system should be shortened in order to avoid shadings on the Adani modules.
The cleaning frequency shall be increased due to the low tilt angles that accelerate the soil accumulation.
All objects on top of the modules shall be immediately removed. The white traces on the module surface shall be removed.
A regrouping of the JJ modules shall be conducted according to the shading conditions. Modules from the same category shall be installed in the same string or at least assigned to one unique MPPT.
All modules showing product and performance issues shall be replaced according to the warranty terms.
All cable connections to the inverter shall be checked.