Protecting distance calculation of reradiation interference on AM broadcasting station from UHVDC power line

In the construction of UHVDC power line in China, the national standard of reradiation interference protecting distance between UHVDC power line and receiving station of AM broadcasting needs to be renewed. In this paper, the wire-surface simulation model is used to calculate the interference. In the model, steel tower is represented as surface model, ground wire is represented as wire model, and the whole model is excitated by vertical polarization plane wave. For the deficiency of traditional solution method of protecting distance calculation, a new method is proposed. It is recommended that the whole work frequency band of receiving station should be calculated to determine the space interval which has actual protecting distance. Then the interval is gradually narrowed with dichotomy method until the interval size is within allowable value. With the first-grade receiving station of AM broadcasting as example, the reradiation interference protecting distance from UHVDC power line and station is calculated.