虽然实验取得了成功，并且表明调整间隙距离可以达到防雷保护的目的，但最好的解决方案仍需要进一步优化，包括固定的方式，电极的材料、安装方式，两个环形电极在动态旋转中的倾角摆动及误差率产生的影响。

　　5.Conclusions

In this paper the author has proposed a novel method that utilizes two ring-shaped electrodes for lightning protection of wind turbines. The most important and innovative point of the proposed system is a pair of ringshaped electrodes arranged with a narrow gap, where the air discharges to flow the surge current when a lightning strikes the wind turbine.1/100 downsized model of a wind turbine with ring electrodes was manufactured. The results of impulse experiments clearly showed that the proposed model can operate safely.
Especially, when the gap between the two rings is larger than the distance between the upper ring and the nacelle, it is clear that a spark-over certainly occurs and the lightning protection system functions satisfactorily.The author is also investigating FDTD electromagnetic calculations for the present model [10,11].It was confirmed that the results of the calculations also agree well with the experimental results.
 problems remain for the proposed method. For example, the method of fixation and installation costs need resolving from a civil engineering viewpoint. Also, any adverse impact on power generation capacity should be discussed from the viewpoint of fluid dynamics. However, in respect of lightning protection, i.e. utilized capacity and generating cost, the proposed system can be expected to maintain the reliability and safety of operations for wind power generation.
Acknowledgements
The author thanks Dr. Matsubara Ichiro, former lecturer of Osaka University, for his help in the operation of impulse testing and for a fruitful discussion on the methodology of lightning protection. The author also thanks Mr. Yoshioka Takuma, Mr. Fujii Toshiaki and Mr. Yamashita Shogo, graduate and undergraduate students of Kansai University, for their help in the impulse tests.

　　5.结论

　　在这篇文章中作者提出了新型的利用环形电极间隙放电器作为风力发电机组直击雷防护的一种方法，其中最重要和具有创新性的点在于如何控制两个环形放电器的间距，使雷电通过间隙时不受风速对电流弧的影响，通过1:100的风机模型及模拟雷击实验的结果清楚的表明这种方式是可行的、安全的。虽然在环形电极间隙距离大于轮毂环形电极于机舱间距时会造成轮毂环形电极与机舱的放电，但并不影响该套方案的有效性，通过后续的优化方案这种防雷系统的效果也是能够令人满意的。同时作者还在运用FDTD时差法计算，间隙通过雷电流时的电磁抵消情况，但可以肯定的是电磁能量的抵消情况应该与实验结果相吻合。

　　当然这套防雷系统仍存在一些问题，例如这个系统的定位和安装需要从工程安装角度来解决，并且安装后可能对机组的整体气动性能方面会存在怎样的影响，还需要进一步讨论。无论如何，这种方案的提出对于机组的雷电防护、实际有效性、安全性能和可实施性都被寄予了很大希望。

　　特别感谢

　　作者感谢大阪大学前讲师MatsubaraIchiro博士，在雷电脉冲测试实验的执行中以及机组的防护方法上提出富有成效的建议以及帮。同时还要感谢YoshiokaTakuma先生、FujiiToshiaki先生和YamashitaShogo先生这些関西大学毕业和没有毕业学生在雷击实验中给予的帮助。