HVDC insulation systems: effect of voltage polarity inversion slew rate on partial discharge phenomenology and harmfulness

Naderiallaf, Hadi; Ghosh, Riddhi; Seri, Paolo; Montanari, Gian Carlo

Abstract

The design of HVDC insulation systems has to take into account various factors which can be neglected under AC, especially the dependence of conductivity on temperature and field and the issue of electric field transient during energization and polarity inversion. The electric field transient in the presence of temperature gradients and/or inhomogeneities, as cavities, can take significantly long times to go from the initial permittivity-driven distribution to that pertinent to DC-steady state, where conductivity rules the field profile in insulation and its maximum value. If conditions occur that can incept partial discharges, in steady state and/or during transient, they can cause considerable damage to insulation. When the mean voltage transient rate during operation is significant, aging can be locally accelerated, and the overall insulation life and reliability reduced. This paper focuses on possible remedy actions, which are related to the amount of damage as a function of voltage slew rate and of rest time between opposite-polarity voltage steps. The impact of voltage rise time during voltage polarity inversion on PD magnitude and repetition rate, and relevant damage, is analyzed based on experimental measurements and an aging model. It is shown that lower voltage slew rate and shorter rest time at a constant voltage slew rate can be beneficial to reduce the damage associate to PD incepted during voltage transients.

Citation

Naderiallaf, H., Ghosh, R., Seri, P., & Montanari, G. C. (2021, November). HVDC insulation systems: effect of voltage polarity inversion slew rate on partial discharge phenomenology and harmfulness. Presented at 22nd International Symposium on High Voltage Engineering (ISH 2021), Xi'an, China and online

• Presentation Conference Type: Edited Proceedings
• Conference Name: 22nd International Symposium on High Voltage Engineering (ISH 2021)
• Start Date: Nov 21, 2021
• End Date: Nov 26, 2021
• Online Publication Date: Mar 29, 2022
• Publication Date: 2021
• Deposit Date: Nov 26, 2024
• Publisher: Institution of Engineering and Technology (IET)
• Peer Reviewed: Peer Reviewed
• Volume: 2021
• Issue: 15
• Pages: 7-12
• Series ISSN: 2732-4494
• Book Title: 22nd International Symposium on High Voltage Engineering (ISH 2021)
• DOI: https://doi.org/10.1049/icp.2022.0002
• Public URL: https://nottingham-repository.worktribe.com/output/40850703
• Publisher URL: https://digital-library.theiet.org/doi/10.1049/icp.2022.0002