Comprehensive Study of Switching Overvoltages in Transmission Line of Northern Laos Power Grid Interconnected Across Pakbeng–Tha Wang Pha Region
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Abstract
Switching and temporary overvoltages pose critical challenges to the reliable operation of extra-high-voltage (EHV) transmission networks. This study analyzes the 500 kV Pakbeng–Tha Wang Pha (PKB–TWP) cross-border interconnection between Laos and Thailand, an essential corridor for regional hydropower integration. A probabilistic electromagnetic transient (EMT) model was developed in PSCAD/EMTDC to evaluate switching overvoltages (SOV) and temporary overvoltages (TOV) under realistic operating conditions. Monte Carlo simulations incorporating Gaussian breaker pole scatter and representative TOV scenarios-such as the Ferranti effect, load rejection, and transformer inrush-were performed. Uncontrolled line energization produced surges up to 2.251 p.u., while reclosing after three-phase-to-ground faults reached 3.445 p.u., both exceeding the ≈2.0 p.u. insulation coordination threshold. The coordinated application of 444 kV metal-oxide surge arresters (MOSA) and 110 Mvar shunt reactors successfully reduced all surges below 2.0 p.u., ensuring compliance with IEC 60071-2 withstand requirements. Temporary overvoltages were contained within an acceptable level: 1.157 p.u. (Ferranti effect), 1.317 p.u. (90% load rejection), and 1.71 p.u. (transformer inrush). Spatial analysis identified resonance hotspots near midline sections, emphasizing the importance of distributed monitoring. Overall, the PKB–TWP interconnection was verified to be technically robust; the proposed methodology offers a practical framework for future EHV insulation coordination in Southeast Asia.
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References
International Electrotechnical Commission, IEC 60071-2:2018, Insulation co-ordination—Part 2: Application guidelines. Geneva, Switzerland: IEC, 2018.
CIGRE WG 13.02, “Switching overvoltages in EHV and UHV systems with special reference to closing and reclosing transmission lines,” Electra, 1973.
T. Keokhoungning, S. Premrudeepreechacharn and K.
Ngamsanroaj, "Evaluation of Switching Overvoltage in
kV Transmission Line Interconnection Nam Theun
Power Plant to Roi Et 2 substation," 2009 AsiaPacific Power and Energy Engineering Conference,
Wuhan, China, 2009, pp. 1-4.
K. Ngamsanroaj and W. Tayati, “An analysis of switching overvoltages in the EGAT 500 kV transmission system,” in Proc. Large Engineering Systems Conference on Power Engineering (LESCPE), 2003, doi: 10.1109/LESCPE.2003.1204695.
K. Ngamsanroaj, S. Premrudeepreechacharn, and N. R. Watson, “500 kV Single Phase Reclosing Evaluation Using Simplified Arc Model,” International Journal of Emerging Technology and Advanced Engineering, vol. 4, no. 6, pp. 1–12, Jun.2014
R. R. Nunes and W. do Couto Boaventura, “Insulation Coordination Considering the Switching Overvoltage Waveshape—Part I: Methodology,” IEEE Transactions on Power Delivery, vol. 24, no. 4, pp. 2434–2440, 2009, doi: 10.1109/TPWRD.2009.2028477.
R. R. Nunes and W. do Couto Boaventura, “Insulation Coordination Considering the Switching Overvoltage Waveshape—Part II: Application and Results,” IEEE Transactions on Power Delivery, 2009, doi: 10.1109/TPWRD.2009.2028476.
Y. Li, J. He, J. Yuan, C. Li, J. Hu, and R. Zeng, “Failure Risk of UHV AC Transmission Line Considering the Statistical Characteristics of Switching Overvoltage Waveshape,” IEEE Transactions on Power Delivery, vol. 28, no. 3, pp. 1731–1739, 2013, doi: 10.1109/TPWRD.2013.2252238.
T. Quoc, S. Du, et al., “Temporary overvoltages in the Vietnam 500 kV transmission line,” ESMO ’98IEEE 8th International Conference on Transmission and Distribution Construction, Operation and Live-Line Maintenance,1998,doi:10.1109/TDCLLM.1998.668378.
International Electrotechnical Commission, IEC 60099-4:2014, Surge arresters—Part 4: Metal-oxide surge arresters without gaps (MOSA). Geneva, Switzerland: IEC, 2014. [Online].Available: https://webstore.iec.ch/en/publication/735
V. Hinrichsen, “Continued Development of Metal Oxide Surge Arresters,” INMR Magazine. [Online]. Available:https://www.inmr.com/challenges-in-continued-development-of-metal-oxide-surge-arresters/ (accessed Oct. 1, 2025)
IEC 60099 5:2018 RLV, Surge arresters—Part 5: Selection and application recommendations. Geneva, Switzerland: IEC, 2018. [Online]. Available: https://webstore.iec.ch/en/publication/33842
“A review of switching overvoltage modeling in UHV AC transmission lines,” Electric Power Systems Research, 2024. [Online]. Available: https://colab.ws/articles/10.1016/j.epsr.2024.110902
H. Ren, X. Wei, and H. Wu, “Influence of line current limiting reactor on temporary overvoltage of 500 kV transmission line,” Journal of Physics: Conference Series, vol. 2592, no. 1, 2023, doi: 10.1088/1742-6596/2592/1/012062.
A. A. O. Akinrinde, A. Swanson, and I. Davidson, “Investigation and Mitigation of Temporary Overvoltage Caused by De Energization on an Offshore Wind Farm,” Energies, vol. 13, no. 17, 2020, Art. no. 4439, doi: 10.3390/en13174439.
M. Pan, Y. Liu, and H. Zhang, “Simulation Model of UHV AC Transmission System Based on PSCAD,” in Lecture Notes in Electrical Engineering, vol. 1000, Springer, 2022, pp. 481–489. doi: 10.1007/978-981-19-3632-6_48.
A. De Silva and D. Kothalawala, “Modelling Cables and Transmission Lines with PSCAD/EMTDC,” PSCAD Knowledge Base, 2023. [Online]. Available: https://www.pscad.com/knowledge-base/download/transmission_line_and_cables_v6.pdf
Q. Yao, Y. Liu, and Z. Wang, “Simulation and research on over-voltage suppression for high voltage transmission line,” Journal of Engineering, vol. 2018, no. 16, pp. 3060–3064, 2018. doi: 10.1049/joe.2018.8730.
IEEE Power & Energy Society, IEEE Recommended Practice for Initialization of Electromagnetic Transient Simulations, IEEE Std 1234-2019.
