Transient Overvoltage Analysis During Capacitor Bank Switching in 35 kV Energy Systems

Gulgaz Gulaga Ismayilova, Nahid Mufidzade, Hamza Houassine

Abstract

Reactive power compensation improves voltage regulation, reduces power losses, and enhances the reliability of electrical systems. In medium-voltage (35 kV) networks, static capacitor banks (SCBs) are widely used for reactive power compensation. However, direct connection of SCBs to substation bus systems forms switching circuits with very low active resistance, causing severe transient overvoltages during switching operations, particularly under synchronous three-phase switching with non-simultaneous zero crossing of phase currents. This work assesses conventional SCB connection schemes and evaluates switching overvoltages for SCBs equipped with discharge elements of various types and resistances, as well as analyzes effective protection measures. The study employs mathematical modeling via computer simulation in the OrCAD X Professional environment. Results show that SCB energization  both without discharge elements and with voltage transformers or resistors of 119 kΩ and 120 kΩ  leads to voltage increases of 1.4–1.7 times, while SCB disconnection produces dangerous overvoltages in substation bus systems. Surge arresters limit these overvoltages by a factor of 3–4, though frequent switching may still accelerate insulation aging. Additional overvoltage mitigation is achieved by introducing supplementary resistance into the switching circuit or by applying two-pole switching schemes. The findings demonstrate the inefficiency of conventional SCB connection schemes and substantiate practical methods for overvoltage protection.

Keywords

Compensating devices; transients; overvoltages; discharge resistances

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References

1. R. T. Lima, A. L. M. Coelho, G. B. Vitor and P. A. V. D. Liz, “An approach to enhance the controlled switching of circuit breakers equipped with preinsertion resistors for power capacitor banks,” Energies, vol. 18, no. 16, p. 4356, 2025. doi: https://doi.org/10.3390/en18164356

2. A. Warizmi, I. Roza and A. Yanie, “Transient analysis on switching capacitor bank using power factor regulator,” J. Renew. Energy Electr. Comput. Eng., vol. 5, no. 1, pp. 86–92, 2025. doi: https://doi.org/10.29103/jreece.v5i1.18707

3. X. Wang, M. Aydin and H. Kantarci, “Switching over-voltages and mitigation methods in sustainable power systems with renewable energy integration,” Renew. Sustain. Energy Rev., vol. 226, 116220, 2025. doi: https://doi.org/10.1016/j.rser.2024.116220

4. Q. Zhang, Y. Li and Z. Chen, “Coordinated optimization of multiple reactive power compensation devices to reduce transient overvoltage peaks,” Energies, vol. 10, no. 5, p. 80, 2025. doi: https://doi.org/10.3390/en10050080

5. T. Eliyan et al., “Evaluation of the efficacy of transient overvoltages suppression measures in different wind farm topologies,” Sci. Rep., vol. 13, 40768, 2023. doi: https://doi.org/10.1038/s41598-023-40768-4

6. H. Chen, J. Tee, M. Elnahass and R. Ahmed, “Assessing the environmental impacts of renewable energy sources: A case study on air pollution and carbon emissions in China,” J. Environ. Manage., vol. 345, art. no. 118525, 2023. doi: https://doi.org/10.1016/j.jenvman.2023.118525.

7. M. Aydin and S. C. Cebeci, “Advanced transient damping methods for capacitor bank switching in weak grids,” IEEE Trans. Power Del., vol. 38, no. 4, pp. 2209–2218, 2023. doi: https://doi.org/10.1109/TPWRD.2023.3178483

8. Y. Zhang and H. Zhu, “Transient overvoltage suppression in capacitor bank energization using adaptive preinsertion techniques,” IEEE Trans. Power Syst., vol. 38, no. 3, pp. 2544–2553, 2023. doi: https://doi.org/10.1109/TPWRS.2022.3215724

9. L. Zhou, W. Li and Q. Huang, “Modeling and analysis of high-frequency transients during MV capacitor bank switching,” Int. J. Electr. Power Energy Syst., vol. 146, 108975, 2023. doi: https://doi.org/10.1016/j.ijepes.2022.108975

10. A. Gupta and M. Singh, “Impact of capacitor bank switching on power quality in distribution systems,” IEEE Access, vol. 11, pp. 34121–34130, 2023. doi: https://doi.org/10.1109/ACCESS.2023.3241096

11. S. Das and P. Kumar, “Controlled switching strategies for transient mitigation in shunt capacitor banks,” Electr. Power Syst. Res., vol. 211, 107949, 2023. doi: https://doi.org/10.1016/j.epsr.2023.107949

12. X. Li and G. Chen, “Influence of system parameters on transient overvoltages during capacitor switching,” IEEE Trans. Ind. Appl., vol. 59, no. 2, pp. 1830–1839, 2023. doi: https://doi.org/10.1109/TIA.2023.3237801

13. Y. Sun and C. Wang, “Mitigating switching transients in medium-voltage capacitor banks using coordinated control,” Int. J. Electr. Power Energy Syst., vol. 152, 108995, 2024. doi: https://doi.org/10.1016/j.ijepes.2023.108995

14. B. Liu, J. Wu and N. Chen, “Transient suppression in power systems with distributed capacitor banks,” IEEE Trans. Smart Grid, vol. 15, no. 1, pp. 17–26, 2024.doi: https://doi.org/10.1109/TSG.2023.3274090

15. F. Zhang and S. He, “EMTP simulation techniques for capacitor bank switching transients,” Electr. Power Compon. Syst., vol. 52, no. 6, pp. 625–637, 2024. doi: https://doi.org/10.1080/15325008.2024.8876543

16. J. Li, L. Gao and W. Yu, “Assessing the impact of switching transients on distribution network protection,” IET Gener. Transm. Distrib., vol. 17, no. 10, pp. 2278–2288, 2023. doi: https://doi.org/10.1049/gtd2.12986

17. S. Sharma and R. Sinha, “Transient overvoltage analysis using wavelet transform during capacitor bank energization,” Measurement, vol. 198, 111512, 2023. doi: https://doi.org/10.1016/j.measurement.2022.111512

18. M. Begović and S. Williamson, “Statistical methods for predicting switching transient overvoltages in power systems,” Electr. Power Syst. Res., vol. 210, 107915, 2023. doi: https://doi.org/10.1016/j.epsr.2023.107915

19. P. Kaur and V. Garg, “Nonlinear dynamic model of capacitor bank switching transients in distribution feeders,” IEEE Trans. Power Del., vol. 39, no. 1, pp. 421–430, 2024. doi: https://doi.org/10.1109/TPWRD.2023.3274052

20. A. Ostrowski and M. Prasad, “Analysis of transient phenomena in capacitor switching with surge arresters,” Electr. Power Compon. Syst., vol. 51, no. 8, pp. 701–712, 2023. doi: https://doi.org/10.1080/15325008.2023.8201234

21. N. Reddy and A. Vaibhav, “Measurement and mitigation of capacitor bank switching transients using FPGA-based controllers,” IEEE Trans. Ind. Electron., vol. 71, no. 4, pp. 3734–3743, 2024. doi: https://doi.org/10.1109/TIE.2023.3278189

22. H. Yao, S. Liu and D. Wei, “Online estimation of transient parameters during capacitor bank energization,” IEEE Trans. Instrum. Meas., vol. 73, pp. 1–10, 2024. doi: https://doi.org/10.1109/TIM.2024.3257610

23. E. Rashid and M. Othman, “Impact of capacitor bank switching on power quality indices in smart microgrids,” IEEE Access, vol. 12, pp. 45217–45230, 2024. doi: https://doi.org/10.1109/ACCESS.2024.3478912

24. D. Verma and S. Gupta, “Real-time monitoring of switching transients in MV networks using sensor fusion,” Measurement, vol. 208, 112250, 2024. doi: https://doi.org/10.1016/j.measurement.2024.112250

25. L. Solis, A. Martinez and D. Santos, “Hybrid control of capacitor activation for transient reduction,” Electr. Power Syst. Res., vol. 218, 108150, 2024. doi: https://doi.org/10.1016/j.epsr.2024.108150

26. M. Farag and T. El-Sayed, “Optimization of switching sequences for reducing electromagnetic transients in distribution systems,” IET Gener. Transm. Distrib., vol. 18, no. 2, pp. 413–422, 2024. doi: https://doi.org/10.1049/gtd2.12902

27. A. Singh and J. Kumar, “Fault-induced delayed voltage recovery due to capacitor bank switching,” IEEE Trans. Power Syst., vol. 39, no. 2, pp. 1831–1840, 2024. doi: https://doi.org/10.1109/TPWRS.2024.3294127

28. R. Verma and S. Chatterjee, “Controlled switching sequences for reducing transient overvoltages in MV capacitor banks,” IEEE Trans. Power Del., vol. 39, no. 3, pp. 1453–1463, 2024. doi: https://doi.org/10.1109/TPWRD.2024.3298015

29. J. Chavez and P. Mendes, “Analysis of transient overvoltages due to capacitor bank switching in weak grids,” Int. J. Electr. Power Energy Syst., vol. 167, 108598, 2025. doi: https://doi.org/10.1016/j.ijepes.2024.108598

30. Mufizada N.A., İsmayilova G.G. Determination of the dependenc of overvoltages on fault currents during the clearance of a short circuit in medium voltage networks. International Journal on Technical and Phisical Problems of Engineerng (IJTPE) – İssue 58, Volume 16, Numder1,

DOI: http://dx.doi.org/10.47238/ijeca.v11i1.305

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