Low Broadband Transmission Line Model for Geomagnetically Induced Current Analysis

A time domain frequency dependent model for transmission lines in low frequency range is proposed. The model considers the frequency dependent parameters of overhead conductors and soils. The targeted frequency range is zero to 1.2 kHz which is sufficient for geomagnetically induced current analysis in transmission circuits. The accuracy of the model in this frequency range is documented by comparing it to Carson's equations. The proposed model achieves high accuracy with minimal computational burden. The use of the model is illustrated with a GIC test case analysis.