Citation :

M Naga Jyothi, C.V.K. Bhanu, "Investigation of Resonance Condition in OFF Shore Wind Park during Energization Events," International Journal of Electrical and Electronics Engineering, vol. 13, no. 9, pp. 93-102, 2026. Crossref, https://doi.org/10.14445/23488379/IJEEE-V13I9P108

Abstract

Transformer energisation in offshore High-Voltage Alternating Current (HVAC) transmission systems can result in significant transient and temporary overvoltages due to the interaction between transformer magnetising inrush currents and network resonances. A detailed Electromagnetic Transient (EMT) model comprising a Thevenin-equivalent grid, frequency-dependent cable representation, and a saturable transformer model was developed to analyse the switching behaviour of the system. Wind Turbine Transformers (WTTs) are experiencing high dielectric stress due to transients induced during energization and de-energization events in offshore wind parks. This paper investigates the energisation of WTT connected to an onshore grid through a HVAC export cable under weak-grid conditions, the resonance potential on the terminal of WTT is assessed. A black box model of a 300 kVA transformer is derived by measurement and implemented in ATP. Vector fitting is used in establishing the frequency domain model and lumped parameter RLC description of the transformer is introduced in ATP as a user specified component. More Emphasis is given on the accurate modeling of cable-transformer energization as well as cable ground fault. Finally, transients induced during switching in an array of Wind Park are simulated in ATP to identify resonance situations and transformer terminal voltages.

Keywords

Black box modeling, Energization transients, Induced over voltages, Offshore wind farm, Resonant frequency.

References

1. Ilipe Miguel Faria da Silva et al., “Evaluation of Temporary Overvoltages in Power Systems due to Low Order Harmonic Resonances,” International Council of Large Electricity Networks, 2023.
   [Google Scholar] [Publisher Link]
2. CIGRÉ, Transformer Energization in Power Systems: A Study Guide, CIGRE, 2014. [Online]. Available: https://www.e-cigre.org/publications/detail/568-transformer-energization-in-power-systems-a-study-guide.html
3. Norme Horizontale, “Insulation Co-Ordination–Part 1: Definitions, Principles and Rules,” 2019.
   [Google Scholar]
4. Lars Liljestrand et al., “Transients in Collection Grids of Large Offshore Wind Parks,” Wind Energy, vol. 11, no. 1, pp. 45-61, 2008.
   [CrossRef] [Google Scholar] [Publisher Link]
5. Gustav Sundberg, “Resonant Overvoltages Caused by Transformer Energization and Saturation: Two EMT Case Studies Conducted using Models of the Grid in Stockholm and an Off-Shore Wind Farm,” 2021.
   [Google Scholar]
6. E. Bjerkan, and H.K. Høidalen, “High Frequency FEM-based Power Transformer Modelling: Investigation of Internal Stresses due to Network-Initiated Overvoltages,” Electric Power Systems Research, vol. 77, no. 11, pp. 1483-1489, 2007.
   [CrossRef] [Google Scholar] [Publisher Link]
7. Juan A. Martinez-Velasco, and Francisco González Molina, Temporary Overvoltages in Power Systems, Power System Transients, Encyclopedia of Life Support Systems, 2012.
   [Google Scholar] [Publisher Link]
8. Marjan V. Popov, L. van der Sluis, and R.P.P. Smeets, “Evaluation of Surge-Transferred Overvoltages in Distribution Transformers,” Electric Power Systems Research, vol. 78, no. 3, pp. 441-449, 2008.
   [CrossRef] [Google Scholar] [Publisher Link]
9. Alberto Borghetti et al., “Lightning-Induced Overvoltages Transferred through Distribution Power Transformers,” IEEE Transactions on Power Delivery, vol. 24, no. 1, pp. 360-372, 2009.
   [CrossRef] [Google Scholar] [Publisher Link]
10. Juan A. Martinez-Velasco, and Francisco GonzálezMolina, “Temporary Overvoltages in Power Systems,” Encyclopedia of Life Support Systems, pp. 1-26, 2012.
    [Google Scholar]
11. Hun-Chul Seo, and Gi-Hyeon Gwon, “Systematization of the Simulation Process of Transformer Inrush Current using EMTP,” Applied Sciences, vol. 9, no. 12, pp. 1-16, 2019.
    [CrossRef] [Google Scholar] [Publisher Link]