Wind Turbine Lightning Protection
The ever-expanding popularity of wind generated power in order to satisfy both needs and desires for cleaner production methods is hindered and slowed by issues that have no absolute solutions. In these circumstances, the best solutions provided are technologically advanced avoidance mechanisms in order to prevent issues from happening. What we are primarily discussing is a major cause of both damage repair cost as well as outages with respect to wind towers as a result of lightning. This issue only grows more severe as the technology used in the wind power generation field grows more sophisticated, and the reliance upon each individual tower to perform becomes more critical. There is no way to assure a total prevention of damage that comes as a result of lightning strikes, so the industry has turned to the most evolved avoidance mechanisms to step in and salvage as much as possible when the inevitable occurs. A “wind tower” is an isolated structure that is physically tall and unobstructed in order to harness the full potential of wind blowing across its blades. Each tower utilizes sophisticated electronic equipment to perform their function. And that equipment is at constant risk of damage as a result of the physical makeup of the tower. Since lightning strikes to the tower or blades is not only commonplace but essentially unavoidable, methods to stop the subsequent power surge and conduct it safely to earth have been the primary method of equipment damage avoidance. These systems will usually cost less than 1% of the operational cost of the tower itself and can improve reliability as well as increase the cost effectiveness of operations to a far larger degree than that 1%.
Research suggests that during the first year of operation of a typical wind tower, once it is installed, more than 85% of downtime is lightning strike related. These studies have also shown that not only are 80% of insurance claims in this field lightning-related, the average totals for lightning damage after a strike exceed $250,000. As a result of these risks, there has been a push within the insurance industry to deny lightning-related coverage. The typical damages that are seen that have high costs are to the control systems and electronics, even though when the strikes happen to the structure and blades they are often destroyed. The blades DO represent the most costly and disruptive damage, but the electronics like the sensors, actuators and motors as well as the transformer stations, frequency converters and switchgear elements represent combined costs that combined can rival blade replacement costs. This electronic gear is generally not completely damaged as a result of the strike but instead suffers due to the surge, and these damages can be avoided through the installation of lightning protection devices on strategic areas of the wind turbine system. Combined with grounding to an existing rod, this setup can avoid a significant amount of damage typically associated with a strike, isolating that damage to the blades and exposed structure. This avoidance technique can save millions of dollars in repair costs every year, increasing productivity and creating a more viable electrical source.