Structural shading

Definition

Unlike vegetation shading, the source of the shade is a permanent structure. The shade moves through the day and across the seasons with the sun's position, but follows the same path every day. The resulting loss is therefore recurring and predictable.

Signs in the imagery

In the RGB image a sharp-edged shadow carrying the shape of the structure falls on the panel surface. The source is identified by comparing the shadow's direction and length with the structure's position and the sun angle at flight time. In the thermal image the shaded cells or substrings may look warm.

Possible causes

• Lighting, camera or lightning protection poles
• Fences, buildings, transformer kiosks and cable trays
• The neighbouring row's shadow when the sun is low in winter
• Structures added later that the layout did not account for

Effect on production and safety

The shade affects the same panels at the same hours every day. The loss at any one moment is small but accumulates over the year. Shaded cells switch the bypass diodes in every day and go through thermal cycling. Because the shade at flight time does not fully reflect the rest of the day, it is important to record the source structure.

Recommended action

Record the source of the shade and assess whether the structure can be moved, shortened or repositioned. For structures that cannot be moved, mark the affected panels on the record so their heating is not confused with other anomalies. When a new structure is added, check its shading effect at the layout stage.