高压输电线对射电望远镜的电磁干扰

Radio Frequency Interference to a Radio Telescope from a High-Voltage Power Line

一方面,根据国际电信联盟(International Telecommunication Union,ITU)关于射电天文的保护标准,结合高压输电线电磁干扰的特性,分析了射电望远镜对高压输电线电磁干扰的限度;另一方面从物理机制出发建立高压输电线电晕放电辐射的电振子模型,运用电振子的镜像法,研究了其辐射功率随距离的衰减规律。同时还考虑500 m口径球面射电望远镜(Five hundred meters Aperture Spherical Telescope,FAST)的具体情况,分析了在FAST周围架设高压输电线应离开望远镜之间最小距离和应注意的问题。

On one hand,this paper analyzes the limits of electromagnetic interference（EMI） from a high-voltage power line torelatable by a radio telescope according to the protection criteria used for astronomical radio measurements recommended by the International Telecommunication Union（ITU） and the characteristics of EMI.On the other hand,this paper presents a study of the distance-dependent attenuation of the corona-discharge radiation based on the physical mechanism of corona discharge,established electric-oscillator model,and the image-charge method for an electric oscillator.This paper also considers particular cases of the Five hundred meters Aperture Spherical Telescope（FAST）,and analyzes the minimum distance to be left between a high-voltage power line and the FAST as well as problems to be noticed. More specifically the paper analyzes the effects of the Radio Frequency Interference（RFI） from high-voltage power lines.There are two main causes of such RFI： the discharge caused by the imperfection of insulation and the corona discharge.The first effect can be mitigated by utilizing better insulation material and through regular maintenance.The paper concentrates on the corona discharge.An oscillating electric-charge model is adopted to calculate the strength of the interference generated by the corona discharge,and the influence of the terrain between the power line and the telescope is also taken into account.Taking the ITU criterion ITU-R RA.769-2 for radio astronomy,and considering various FAST observing modes,we give preliminary suggestions on allowable distances from power lines of different voltages.The results should be considered qualitative only,as the allowable distances need to be further refined according to the terrain around the region and the shape of the telescope antenna.