Solar projects: No compromise on material and workmanship quality

Highlighting the common issues that have plagued several solar projects across the country over their operational history.

Over the past few years, Excelsior Engineering Solutions has carried out various plant audits and quality checks for several MWs of ground mount and rooftop projects spread across locations in India. The outcome of these audits unravelled certain findings that were quite universal, familiar in characteristic. Even though the projects were installed in different locations by various competing vendors for a diverse clientele with dissimilar technologies, there are several findings to be identical. In this article, we would like to focus on the common issues that have plagued several solar projects across the country over their operational history.

Solar modules
• Formation of hot spots within the cells.
• Snail trails on the modules.
• Failure of bypass diodes in the module junction box.
• Sagging of frameless thin film modules.

MMS
• Lack of code compliance in the design criteria of the structure.
• Utilisation of smaller or lighter sections that are not in keeping with the design to reduce overall material utilisation per MW.
• Absence of concrete or re-bars below the pile foundations.
• Inconsistency in the mixing of concrete used.
• Inaccurate pile foundations leading to misalignment of the structure columns.
• Pile caps of column post missing.
• Holes drilled on the purlins at the fabrication shop being inaccurate leads to on-site drilling; workmanship of such fixes tends to be poor.
• Rusting of parts due to improper galvanisation.
• Sagging and buckling of structures.
• Aluminium sections of inadequate load bearing capacity being used for rooftop installation.
• Rusting of fasteners and the threading of the bolts being worn off.
• Nut bolts mounting the module to the structure are found loose.
• Necessary grade of fasteners not being used.

Inverter
• Central inverters not maintained properly. Layers of dust are found inside the equipment.
• Inadequate equipment earthing.

Trench
• Route markers essential to identify cable routing missing.
• Inconsistent depth of trench in reference with design drawings.
• Bricks, safety tapes, non-rocky sands missing in the trenches.
• Mixing of AC cables along with communication and DC cables in the same trench.

Grounding
• Shearing of the bonding between the earth strip and the earth rod.
• Structure grounding disconnected from the earth strip.
• Interconnected AC and DC earthing.
• Post installation verification of earth resistance values not carried out.

Cables
• Cables missing proper tagging/ferruling making it difficult to trace the cables during fault finding.
• Improper crimping of lugs at the equipment.
• Cable insulation is not tested post installation to find if any damage took place done during laying of cables. This results in faults occurring in the system.
• Use of inferior quality cable.

Civil works
• Due to the use of local and un-skilled workers at site, several issues arise with the civil works of control room, equipment foundations, peripheral walls etc.
• Proper compacting of the ground not being carried out causes the building or equipment to tilt post the monsoon.
• High speed winds damaging doors and causing street lights to fall.

O&M
• It is a common notion by several clients that cleaning modules regularly is the sole O&M practise to be carried out.
• Preventive and predictive maintenance activities of equipment’s are hardly ever undertaken.
• No proper records of spare parts consumption, fault analysis or grid shutdown are found.
• Personnel’s on site are not given professional training to handle the equipment and safety procedures to be followed.

The above observations are not the findings of any single project. These are common observations made by Excelsior site team. To counteract aggressive bidding by cutting corners for small savings, will always be met with a negative impact on the project. We are at the dawn of an energy revolution. The solar projects will not be able to withstand 25 years of working lifecycle if we compromise on the material and workmanship quality.

Authored by__

Uday Doshi, Founder,
Excelsior Engineering Solutions