Using Simulation to Reduce Damage and Maximize Availability in Wind Turbine Applications
Lightning effects on wind turbine blades present significant challenges to manufacturers and operators. The industry is skewing heavily towards larger wind turbine blades and more remote locations, and these pose substantial logistical challenges in terms of accessibility, cost of repairs, and increased downtime when issues arise. Particularly in the case of lightning, arcing and direct effects damage can render an entire wind turbine useless if not properly mitigated. With the ever increasing length of wind turbine blades, the electromagnetic environment becomes increasingly complex. Tall wind turbines can physically penetrate clouds and placing them in close proximity to charged regions. This can cause intense internal electric fields inside the blade that commonly produce streamering for long durations (which can ruin the integrity of high voltage cabling). Likewise, the mechanical stresses associated with these length increases are driving manufacturers towards carbon-based designs, which bring arcing and flashover considerations in to play. Testing of full-scale wind turbine blades is enormously expensive and time consuming, and there are few locations in the world capable of conducting these types of tests. Simulation and analysis presents a novel approach which can allow for the accurate analysis of the electromagnetic environment, allowing for engineers to study the performance of potential lightning protection systems, performance of dielectrics in the installed wind turbine environments, and assess performance differences associated with in field repairs.
In addition to these capabilities, a thorough understanding of the installed environment can be a tremendous cost saver for operators and manufacturers. Using environmental data from similar geographic locations and coupling this with available terrestrial lightning data provides previously never before available insights as to the real lightning threat facing a blade. It is well understood that lightning severity, frequency, and type (positive, negative, etc.) are geographically influenced, and the deployment location can provide insights as to the severity of the electromagnetic environment a wind turbine must be capable of operating in. Utilizing simulation and analysis for these cases, in addition to evaluating the effects of lightning through accurate 3D models has presented the industry with the ability to reduce cost and downtime by allowing for their true performance to be studied.
Justin McKennon is a Principal Scientist at Electro Magnetic Applications and an industry recognized leader in understanding and simulating the effects of lightning and other electromagnetic effects, having published dozens of papers and been an invited speaker at numerous conferences and events. He obtained his Bachelor’s and Master’s degrees in Electrical Engineering from the University of Massachusetts. He holds an FAA Designated Engineering Representative license in all lightning disciplines. His areas of expertise are in lightning effects on aircraft, wind turbines, systems, etc., finite element analysis, aircraft certification, and electromagnetic effects. He has previously worked for large defense contractors, and recently served as the Chief Engineer of NTS Lightning Technologies.