Drone inspection of wind turbine lightning protection systems (LPS)
Highlights
- 10 times faster than traditional methods (inspection time cut by 90%)
- Compliant to the EN 62305-3 standard
- Complete inspection of the LPS system by measuring resistivity of each receptor
- Measure receptors at up to 200 m height
- No need to rotate blades, inspection carried out in a Y configuration
Problem Description
Wind is a renewable energy source that is clean, free, and widely available. Every day, an estimated 260'000 wind turbines capture wind energy and convert it to electricity worldwide.
Despite the fact that wind turbines are outfitted with LPS, lightning strikes continue to destroy blades and entire turbines. Given that wind turbines have a design life of up to 25 years, it is critical to protect them against lightning strikes, since the damage caused by lightning strikes may result in downtime of the turbine operation, additional maintenance expenses, and a lack of power. According to recent research, lightning strikes caused 85% of downtime and were the source of 80% of insurance claims. As a result, a well-working LPS system is critical.
The traditional rope access technique is time-consuming and carries all the risks of working at height.
Solution Description
Voliro T is equipped with the LPS tester payload, a needle probe which is used to create contact with the LPS receptor. The payload is connected to a tether cable which connects the needle probe on the drone with a Micro-Ohmmeter on the ground. To close the loop, the Ohmmeter is grounded to the wind turbine.
When the sensor carried by the Voliro T is in contact with the LPS receptor, the loop is completed and the bulk resistivity measurement can be recorded.
From trials on an onshore wind turbine farm, the complete LPS measurements on a 3.5 MW turbine were completed in just 40 minutes, saving almost a day over traditional rope access methods. Due to the 250 m tether length, blades can be expected in any position and do not need to be rotated during the inspection.
