An ATP-EMTP-based model for analysis of shielding properties of ferromagnetic cable sheaths

Ferromagnetic materials, such as steel, are used for shielding of power and telecommunication cables. These shields often provide path for currents during faults or lightning and are important for the integrity and safety of electrical systems and devices. Since such currents might be with low- or high-frequency content, and of low or high intensity, ferromagnetic shield behavior might be quite different due to hysteresis. This paper describes a method for analyzing the dynamic behavior of ferromagnetic cable shields based on the Jiles model of hysteresis. The solution is implemented in ATP-EMTP, which allows one to analyze the complex behavior of ferromagnetic cable shields in conjunction with that of the other elements of the power system. Due to limitations of the model of hysteresis, application of the proposed model is limited to frequencies up to about 10 kHz. The model is illustrated for a practical 100-m-long cable.