磁共振式无线输电样机对计量和开关的电磁影响分析

Analysis of Electromagnetic Influence of Magnetic Resonance Wireless Transmission Prototype on Metering and Switches

无线输电技术与常规有线电能传输相比,具有方便灵活、高效、节省空间等优点,成为了热点技术。与能量在自由空间传播相比,无线输电的电磁环境有很大不同,而电磁安全问题也变得日益突出。针对此问题,首先设计并研制了6组百瓦级多频点无线输电样机,然后利用电磁测试仪器Narda-NBM520测试了不同工作频率下的无线输电样机周围的电场强度、磁场强度和功率密度,并与电磁辐射公众安全限值进行对比,结果表明在距离线圈50 cm以上时电场强度、磁场强度和功率密度才符合安全标准。最后分析了无线输电样机对电网接入点的计量和电子开关的影响,结果表明,电表在高频磁场影响下出现了部分计量偏差,极限情况下电子开关出现了损毁情况。

Convenient, flexible, efficient and space-saving compared with conventional power transmission cable, wireless transmission technology（WPT） has become a hot technology. Compared to power transmission in free space, electromagnetic environment of WPT is very different, and its electromagnetic security issues become increasingly prominent. In this paper, six sets of hundred watt multi-frequency wireless transmission prototypes are designed and developed. Electric field strength, magnetic field strength and power density around the wireless transmission prototypes in different operating frequencies are tested using Narda-NBM520, and its results are compared with electromagnetic radiation safety limits for public. It shows that when testing point is at 50 cm above coils, electric field strength, magnetic field strength and power density meets safety standards. Finally, influence of wireless transmission prototype on metering and electronic switches at grid access point is analyzed. Results show that measurement error exists in meters under influence of high-frequency magnetic field, and electronic switch damage appeared in extreme cases.