| The passive interference of transmission lines to nearby radio stations may affect the effective reception and transmission of radio station signals.For theradar stations,high-voltage overhead transmission lines and other facilities as obstacles,if it is too close to the radar station,it will destroy the requirements of the radar position reflecting surface,at the same time,it will deform the radar lobe,and then it affects the detection performance;and it also cause a certain shielding angle or electromagnetic wave attenuation to the radar,this leads to the radar misses the target or the detection distance is reduced.Therefore,it is the basis for determining the reasonable avoidance distance between the two.In order to study this problem,Firstly,this paper analyzes and summarizes the radar station protection requirements and influencing factors,and then concludes that overhead conductors are the main aspects that affect the passive interference of transmission lines to radar stations.Secondly,based on the analysis of the overhead conductor model,and verified the most suitable modeling and calculation methods for the above problems is the triangular face model and the physical optics method.Then,based on the above conclusions,several main component parameters such as the sub-wire radius,equivalent radius and position of the overhead conductor are studied.The results show that the sub-wire radius and height have little effect on the passive interference of the radar;the frequency demarcation point of the split conductor and the equivalent radius conductor is 450MHz;the horizontal arrangement of the conductor does not have the problem that the radar-oriented antenna obscures the influence of the rear conductor.Finally,the paper simulated the influence law of different line arrangement forms of UHV AC and DC lines and corridor-erection on radar detection power,and gave the avoidance distance of transmission line and radar station according to the actual situation.That is,the distance between the single-circuit AC or DC transmission line and the radar station is recommended to be uniformly considered according to 4 km;the distance between the transmission line of the double-return UHV AC drum tower and the radar station is recommended to be uniformly considered according to 5 km;The distance between the double-return UHV AC+single-turn UHV DC transmission line and the corridor erection and the radar station is recommended to be considered in accordance with 5.5 km;The distance between the double-return UHV AC+two single-turn UHV DC transmission line and the corridor erection and the radar station is recommended to be considered in accordance with 6 km. |
