Abstract: The substation is the hub of the power grid system. With the emergence of 5G technology, an increasing number of 5G base stations are being planned within substations. However, the power frequency electromagnetic interference generated by the power transmission lines inside substations significantly impacts the deployment of communication equipment in 5G base stations. In this scenario, studying the effects of power frequency electromagnetic fields within substations on 5G base stations is particularly crucial. This paper physically modeled a substation, calculating the power frequency electromagnetic fields within the station. Simulations were conducted to model the power frequency electromagnetic field environment of the 220kV and 500kV transmission lines at the station, and the accuracy of the substation model was verified through comparison with measured results. Finally, analysis of the power frequency electromagnetic fields of the transmission lines at different heights led to the determination of the deployment range of 5G base stations. This study provides theoretical references for the deployment of 5G base stations within typical substations.