Modeling of DC asymmetrical faults in bipolar HVDC links with metallic return
C. Wijnakker, J.L. Rodríguez-Amenedo, F. Arredondo and S. Arnaltes Departamento de Ingeniería Eléctrica, EPS, Universidad Carlos III de Madrid, Leganés, Madrid (Spain) 2026-02-15

Abstract

This work proposes a compact and flexible dynamicmodel of a bipolar HVDC link with metallic return, suitable for simulation of power systems. The model is formulated compactly using only two matrix equations and is capable of simulating different types of faults, including pole-to-ground, pole-to-neutral and pole-to-pole faults. The inclusion of the dynamic equations of the neutral cable enables accurate asymmetric perturbation dynamic studies. The proposed model has been included as a module in a software framework which is aimed for dynamic simulation studies in AC/DC systems. Results demonstrate the model’s functionality and capability to simulate various fault types, including asymmetric faults, where the neutral cable plays a pivotal role.

Key words: HVDC transmission, metallic return, AC/DC power systems, fault modelling, time-domain simulation.

References

[1] E. Pierri, O. Binder, N. Hemdan, and M. Kurrat, “Challenges and opportunities for a European HVDC grid,” Renewable and Sustainable Energy Reviews, pp. 427–456, 2017, doi: 10.1016/j.rser.2016.11.233.

[2] A. Stan, S. Costinaș, and G. Ion, “Overview and Assessment of HVDC Current Applications and Future Trends,” Energies 2022, Vol. 15, Page 1193, vol. 15, no. 3, p. 1193, Feb. 2022, doi:10.3390/EN15031193.

[3] A. Alassi, S. Bañales, O. Ellabban, G. Adam, and C. MacIver, “HVDC Transmission: Technology Review, Market Trends and Future Outlook,” Renewable and Sustainable Energy Reviews, vol. 112, pp. 530–554, Sep. 2019, doi: 10.1016/J.RSER.2019.04.062.

[4] N. R. Watson and J. D. Watson, “An Overview of HVDC Technology,” Energies (Basel), vol. 13, no. 4342, 2020, doi:
10.3390/en13174342.

[5] “Interconexión eléctrica por el Golfo de Bizkaia | Inelfe.” Accessed: Jan. 22, 2025. [Online]. Available:
https://www.inelfe.eu/es/proyectos/golfo-de-bizkaia

[6] “Offshore Network Development Plans European offshore network transmission infrastructure needs.” Accessed: Jan. 29, 2024. [Online]. Available: https://www.entsoe.eu/outlooks/offshorehub/tyndp-ondp/

[7] O. E. Oni, I. E. Davidson, and K. N. I. Mbangula, “A review of LCC-HVDC and VSC-HVDC technologies and applications,” EEEIC 2016 - International Conference on Environment and Electrical Engineering, Aug. 2016, doi:
10.1109/EEEIC.2016.7555677.

[8] T. Kristian Vrana, J. Beerten, R. Belmans, and O. Bjarte Fosso, “A classification of DC node voltage control methods for HVDC grids,” Electric Power Systems Research, vol. 103, pp. 137–144, 2013, doi: 10.1016/j.epsr.2013.05.001.

[9] R. B. Sinha, “UHVDC transmission with dedicated metallic return,” Proceedings of IEEE International Conference on Technological Advancements in Power and Energy, TAP Energy 2015, pp. 485–488, Aug. 2015, doi: 10.1109/TAPENERGY.2015.7229667.

[10] P. Yang et al., “Analysis on fault characteristic of metallic return in true bipolar VSC-HVDC transmission system,” IET Conference Publications, vol. 2019, no. CP764, 2019, doi: 10.1049/CP.2019.0564.

[11] C. Wijnakker, F. Arredondo, J. L. Rodríguez-Amenedo, S. Delgado-Sánchez, and S. Arnaltes, “Generalized dynamic transient model for MTDC networks covering multiple topologies and contingencies,” Electric Power Systems Research, vol. 243, p. 111469, Jun. 2025, doi: 10.1016/J.EPSR.2025.111469.

[12] C. Yang et al., “Fault protection of multiterminal HVDC networks: Impact of inductance,” International Journal of Electrical Power & Energy Systems, vol. 141, p. 108113, Oct. 2022, doi: 10.1016/J.IJEPES.2022.108113.

[13] “Type 4 - Generic Wind Turbine Generator Model (Phase II) -ESIG.” Accessed: Feb. 03, 2025. [Online]. Available:
https://www.esig.energy/wiki-main-page/type-4-generic-windturbine-generator-model-phaseii/# Plant_level_control_ model_.28repc_a.29

[14] J. Beerten and R. Belmans, “Development of an open source power flow software for high voltage direct current grids and hybrid AC/DC systems: MATACDC,” The Institution of Engineering and Technology, vol. 9, no. 10, pp. 966–974, 2015, doi: 10.1049/ietgtd. 2014.0545.