PRELIMINARY DESIGN REVIEW FOR MODULE MOUNTING ARRANGEMENT AND PLANT LAYOUT
Last week, I was on a site visit of a rooftop solar PV plant. Technical specification and selection of selection of the module, inverter, and cables were fine. But this plant was not doing well. After inspecting the plant, I found the reason. It was structural defects. These defects motivate me to write an article on right and wrong practices of module mounting. So this article is concerned about the module mounting arrangements best practices verses blunders.
Key tips for mounting arrangement of a solar PV plant are:
The electric line layout should be symmetrical to the plant boundary and triple stacking should not be done. Cross-member on the longitudinal section should be provided and Adjustable assembly for tilt should be provided
In the Fig 1, there is a provision to provide tilt and thermal expansion. This will make a robust and useful structure. On the other hand in Fig 2, provision for the tilt is wrongly provided. This won’t work at all and will not allow robust tilt.
Fig 1 Fig 2
Short leg should be 1500 mm distance from the ground. Each member should have a hinge support than a bolt support for allowing thermal expansion. Fig 3 is showing the right way to provide the provision for the thermal expansion. In Fig 4 bolts will not allow the structure to move under thermal expansion. This will lead to introduce a sag in the Solar panel.
Fig 3 Fig 4
Height adjustable module clamps should be provided. But make sure that these will not so tight that it will break the glass. Fig 5 is showing the right way to do this. The way shown in the Fig 6 will lead to breakage of the glass.
Fig 5 Fig 6
To make the system flexible foundation should be made flexible as shown in Fig 7. Fir 8 is wrong practice. This practice made system rigid. If any change required in the design of power plant, Fig 8 kind of structure will not support that change and has to be replaced by the newer design.
Fig 7 Fig 8
By: Gaurav Kumar Sharma, Consultant inn First Green Consulting Pvt Ltd.