Comparison of Frequency Dependent and Pi Section HVDC Cable Models in the Presence of Harmonics

Understanding harmonic propagation in high voltage transmission lines and cables is important for the design and operation of power systems. The presence of harmonics and other transients in transmission and distribution system pose significant risks to insulation coordination aspects and to the safe and reliable operation of various power system components such as transformers, cables, reactors and filters. In this paper simulations are carried out to study the performance of both classical Pi-section and frequency dependent high voltage cable models under different harmonic distortion conditions. Harmonics of different amplitude and frequencies are superimposed on a 100 kV DC voltage and the frequencies evaluated at both the sending and receiving ends of the cable. Total Harmonic Distortion (THD) values are compared for different levels of harmonic distortion and loading. Current and voltage source harmonics are introduced at the input and the output voltage harmonics are analyzed. The simulation results show individual harmonic amplitudes change for the two models resulting in different THD values. The results presented in this paper will help improve understanding of the potential harmonic propagation within HVDC cables and the harmonic impact on HVDC cable insulation.