[Editor’s Note: In addition to turbine and blade inspections, drones are also being used to inspect power lines.]
This post originally appeared on http://www.windpowerengineering.com/maintenance/drones-play-bigger-role-wind-farms/.
By Grant Leaverton, Vice President & General Manager
Advanced Aerial Inspection Resources (AAIR)
Commercial-grade drones are proving to be more than a novelty. Advanced optics, cameras, battery life, data analytic systems, and the ability to remain stable in strong winds means these machines can provide a valuable service at wind farms.
Drone inspections of turbine towers and blades can save a wind-farm owner time, cost, and safety risks over rope-based inspections. Now drones are proving even more useful at wind site, and the safer option for aerial inspection of power lines and transmission infrastructure.
The commercial drone industry is evolving at a rapid pace. Each change or advancement means application of Unmanned Aircraft Systems (UAS) can enter another market and provide a service that typically cuts costs and enhances safety. To date, UASs have provided service in industries such as military, security, search and rescue, construction, agriculture, real estate and land surveying, insurance, and others.
The wind-power industry is no different, and many wind-farm owners capitalized on drone use early with unmanned inspections of their turbines. In some instances this eliminated the need for traditional climbing, and rope-based or platform inspections by wind technicians. UAS have led to significant operations and maintenance savings and, most importantly, reduced safety risks at many wind sites.
While adoption of UAS is increasing, so are the machines, which is leading to new ways and reasons for using them. It is also leading to new techniques and skillsets required for proper and safe drone operation. For example, in the wind industry, turbine and blade inspections are no longer the only useful purpose for UAS. Wind-farm owners are starting to employ them for aerial inspection of power lines and transmission interconnects.
As the reasons for using drones evolve, it is imperative to keep track of the regulatory framework governing their use and maintain skills to operate the new and upgraded machines.
Turbine blades to transmission lines
New drones are entering the marketplace every week. Advancements in autonomous flight, sense-and-avoid features, and feature recognition technologies are now available in many off-the-shelf units.
Drone sensors are getting smaller and smarter. At the same time, the data sets drones are capable of collecting remotely are only getting bigger. This benefits some users who can attain greater use and data, employing drones for more than one task.
The wind industry is a prime example where drones have increased their reach and value. Wind-farm owners are now able to employ drones for tower, blade, and transmission inspections. This is no small accomplishment: where regular blade inspections might prevent an unexpected failure that could bring down a single asset, failure of a wind site’s transmission line could potentially bring the entire park offline.
Today’s commercial drones are ideal for performing comprehensive aerial inspections (CAIs) of transmission assets. A CAI is a highly detailed inspection meant to spot the smallest of defects, such as loose or missing cotter pins on a conductor attachment. UAS-driven CAIs can even detect hairline cracks in critical welds.
This type of inspection reaches far beyond basic aerial patrol and yields a much higher probability of defect detection. The detail and data obtained lets site owners determine the overall health of their system and make early O&M and repair decisions to prevent unplanned outages. In addition to the higher quality of data provided by UAS, drone inspections eliminate the need for helicopters and climbing patrols and provide a safer and more cost-effective option.
Routine transmission-line inspections are just one application where drones are proving useful at wind sites. Storm damage assessment is another. Mother nature can wreak havoc on transmission lines. This is especially true at wind farms, which are purposely situated in high-wind regions. Whether it is 200-plus mile-per-hour winds or an ice or lightning storm that hits a wind site, preventing failure is not always an option. A post-storm assessment is routine O&M protocol at wind farms, and drones can also make this process simpler, safer, and less costly.
For example, downed lines present unique hazards for repair crews, and the ability of UAS to bypass these hazards and provide a real-time view of a work area is of high value for linemen. It lets a repair team identify hazards before workers enter an area and helps them decide on the right tools and equipment for the job. This insight keeps workers safer and expedites the restoration process.
As regulations change, the use of UAS for transmission line inspections will likely become more common. As it currently stands, drones must fly only within visual line of site (VLOS) of the operator. This limits the range of flight to 1,000 to 2,000 feet on average, depending on how large the UAS.
It is expected Federal Aviation Administration (FAA) regulations will change and eventually let beyond visual line of site (BVLOS) operations of UAS. When this happens, users can add long-range aerial patrol to the list of viable uses for transmission line inspection by drones. This provides for a much higher-level inspection of the asset, and is a critical function of managing a right-of-way from possible encroachment and vegetation management.
The FAA’s recent Part 107 “small rules” release moves the industry a step closer to long-distance flights. Part 107, which takes effect August 29, 2016, permits commercial flight of drones weighing less than 55 pounds, at a maximum speed of 100 mph, below 400 ft. AGL (above-ground level) during daytime (and as long as they remain within the line of sight of the operator). Although the new rule does not permit BVLOS operations, it opens discussions by stating that consideration of certain waivers of operational restrictions would take place if the operator could prove an equivalent level of safety.
This means that the line of site restriction may be waived in certain situations. Experts in the utility industry are predicting that certain BVLOS waivers for overhead line inspection will be granted within the next 12 months.
Part 107 has another significant ruling as well. The regulation eliminates the once-required FAA pilot’s license to fly a commercial drone. A UAS pilot certificate is still required but much easier to obtain and can even be done online. This change is significant because it lowers the qualification standards for drone operation and opens the door to new talent.
This may seem unfavorable except that the original regulations were extremely prohibitive to would-be drone operators. Benefits of the new rules include reduced costs to get licensed for drone operation and increased operational flexibility for owners. There are other minor changes in the regulations that are available on FAA’s website.
The advancements in drone capabilities and new regulations for commercial drone use mean it is imperative for users to keep up with the ever-changing UAS industry. These changes also open the door for new industries to take advantage of the many potential benefits drones can offer, and for older industries to research new uses for UAS. As the capabilities of drones advance and the opportunities increase, one thing remains clear, drones are here to stay.