What is an Aerial Solar Inspection?Drones are here to save the day. Benefits include:
- Aerial inspections enable you to document and diagnose panel degradation, scan inverters and data capture vegetation management. Traditional inspections are conducted and are limited to a sample of the site while drones oversee the entire solar project.
- You can check modules output and make a warranty claim if equipment is not generating at optimal levels.
- Drones can survey an entire solar farm to identify faults in a fraction of the time and expense.
Is It a Bird? Is It a Plane?Drones are equipped to capture quality asset data that humans cannot reach with traditional handheld readers. Drone inspections utilize aerial thermal imaging to locate and diagnose faults where electricity production has visibly dropped, allowing owners to act on operational inefficiencies and optimize power generation. Anomalies include cell and string defects, defective diodes, bird or snail debris, inverter problems and short circuits. The following illustrates how these appear under “infrared vision”.
Equipment You Need for an Aerial Solar Panel InspectionWith the right equipment, inspectors can conduct aerial solar inspections more accurately and efficiently. Let’s face it, time is money, so the more effective an inspection, the more owners can see a return on investment (ROI). We recommend the following gadgets in your aerial inspection toolbelt:
- Drone and remote – Not all drones are created equal. Make sure the drone model is suitable for aerial inspections by checking camera compatibility, long battery life and a built-in flight automation feature.
- Infrared camera – An infrared camera can detect faults in heat patterns naked to the human eye. Resolution should be no less than 640×512 and sensor focal length between 13mm-19mm. Dual RGB and thermal images are more advantageous for capturing loss of solar power generation.
- Computer or tablet – A tablet has portable advantages in the field, but a compatible device to access drone software and review asset data is a necessity.
- Solar Irradiance Meter – Measures the amount of solar power panels collected to maintain consistent adequate levels (minimum of 600 watts per square meter).
- Cleaning and repair kit – Retain optimal footage quality and protect your camera from damage in dry, dusty or wet weather with an adequate cleaning kit.
- Computerized Maintenance Management Software – What happens to all that footage? A CMMS like 60Hertz centralizes all maintenance data in a time series database allowing your teams to action urgent maintenance alerts and archive maintenance logs.
How to Conduct an Aerial Solar PV InspectionWith the information above, now you’ll need to know how to conduct an aerial solar PV inspection.
Plot a CourseCompared to traditional hand-held devices that are limited to ground-level data collection, drones are a more economical, accurate and safe method for undertaking solar panel inspection that offer a wider view of potential equipment failures. Daniel McColl establishes that “aerial inspections can be done in a matter of hours and require far less manpower to conduct. Typical aerial inspection drones can cover up to 10 MW per hour, whereas manual inspections would be lucky to cover 1 MW in 10 hours of work.” With that being said, inspectors must plan the most efficient flight route to elevate ROI and capture quality data. Things to consider:
- Flight start times, speed and duration for optimal efficiency and imaging quality
- Plan for poor weather conditions (hail, cloud, acid rain, hurricanes etc)
- Data collection software or a CMMS to automate and action maintenance work orders
- Battery economy and charge duration
- Drone maintenance expenses
- Route planning software to automate the flight path and maintain image consistency (see example below)
Flight Altitude and AnglesAn efficient aerial inspection is expendable if you don’t collect quality data. Plotting the most economical course is critical to capturing quality asset data. Depending on the size of the solar farm, the angle may need to be adjusted to accommodate the moving panels during the flight.
Take Off With the Right Baseline DataThe best time to “get off the ground” with your inspection program is at handover. According to TUV Rheinland’s study, 80% of module defects occur prior to operations. This gives you the chance to establish baseline data with which to compare to later inspections. You should also check for correct installation and that everything is operating as it should.
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How Often Should Solar Panels Be Inspected?Regular health checks are necessary to spot faults before they turn into more expensive problems, maintain asset lifespan and achieve optimal electricity production. Drone Life recommends “to stay on top of your solar plant’s maintenance, you should inspect your solar plant 1-2 times per year.” However, how often you want to carry out these health checks depends on many variables such as:
- Weather conditions such as hail will cause more damage to panels, whereas windy environments can blow dirt and debris
- Buildings or vegetation cause shade on panels, which needs to be monitored and maintained for optimal sunlight exposure.
- Curious animals can chew wiring and migrating birds may decorate your panels on their flight path, requiring more regular cleaning.