Resonance Analysis on Induced Current of Coupling Between Overhead Shielded Cables and Ground
Qiu Riqian · Gao dianya jishu · 2015
In order to theoretically analyze and calculate induced current on cable caused by space electromagnetic field coupling, we obtained the analytic expression of the induced current for different terminal loads of cable by using the transmission line model with a distributed source of aerial shielded cable-ground circuit. Then we analyzed the resonance mechanism of induced current, and acquired the relationship between resonance frequency and cable's length. Additionally, we discussed the relationship among induced current resonance, ground conductivity, and cable's overhead height. The results show that, when resonance occurs in the induced current, its amplitude increases with the cables-ground circuit's time constant. Under preconditions including earth conductivity of 0.01 S/m, irradiation wave frequency of 75 MHz, cable radius of 4 mm, height between cable and ground of 1 m, cable length of 2 m, and both ends of cable being overhead, error between the theoretically calculated result and measured result of the cable induced current is below 5 d B.