Intense Mid-level Wind Speeds and Flat Tracker Tilts during Rear Glass Breakages on Non-Large-Format Bifacial PV Modules on Trackers

We present a follow up investigation of a previous work which showed a correlation between mid-level wind speed and rear glass breakages in non-large-format bifacial modules mounted on single axis trackers in a solar farm. By looking into the time-of-the-day details of the wind speed records, concurrent occurrences of intense mid-level wind speeds (across a short period of time) and relatively flat tracker tilt-angles are found in mid-level wind cluster days just preceding periods of possible module rear glass breakages events. This strongly contrasts with other mid-level wind speed records in this solar farm. It is suggested that the module rear glass breakages could potentially arise from a milder form of tracker torsional galloping that are not strong enough to cause tracker structural damage but strong enough to cause bifacial module rear glass breakages, representing a potentially new module failure mode.