Jeomanyetik Olayların Senkron Generatörlerin Termal Kapasitesi ve Performansı Üzerindeki Etkilerinin Analizi

Öz

Bu çalışmada, jeomanyetik fırtınalar sonucunda enerji iletim sistemlerinde oluşan jeomanyetik indüklenen akımların (JİA), senkron generatörlerin performans parametreleri üzerindeki etkileri incelenmiştir. MATLAB/Simulink ortamında oluşturulan test sistemiyle farklı topraklama direnci ve JİA seviyeleri altında parametrik analizler gerçekleştirilmiştir. Analizlerden, JİA’ların generatör yükseltme transformatörlerinde (GYT’lerinde) doyuma neden olarak mıknatıslanma akımlarının harmonik bileşenlerinde ve reaktif güç talebinde artışa yol açtığı görülmüştür. Bu durumun, senkron generatör rotorlarında aşırı ısınma, alan sargılarında izolasyon bozulması, kayıp artışı gibi termal ve yapısal sorunlara sebep olabileceği ifade edilebilir. Bununla birlikte, düşük topraklama direncinin harmonik bozulmaları ve reaktif güç talebini artırdığı, yüksek topraklama direncinin ise bu etkileri sınırladığı anlaşılmıştır. Ayrıca, zaman gereksinimi olan detaylı simülasyonların yerine Yanıt Yüzeyi Yöntemi (3Y) kullanılarak geliştirilen matematiksel modeller ile JİA etkilerinin hızlı, güvenilir ve yüksek doğrulukla öngörülebileceği ortaya konulmuştur. Elde edilen sonuçlar, eşdeğer negatif sıra akımı (I2eq), toplam harmonik bozulma (THDIG) ve reaktif güç talebi (Q1) gibi temel performans parametrelerinin, JİA seviyesi ve topraklama direnci ile olan ilişkilerinin istatistiksel olarak anlamlı biçimde modellenebildiği gösterilmiştir.

Anahtar Kelimeler

• Jeomanyetik olarak indüklenen akımlar
• senkron generatörler
• generatör yükseltme transformatörleri
• termal kapasite
• yanıt yüzeyi yöntemi.

Destekleyen Kurum

Balıkesir Üniversitesi Bilimsel Araştırma Projeleri Birimi (BAP)

Proje Numarası

2024/045

Teşekkür

Bu çalışma, Balıkesir Üniversitesi Bilimsel Araştırma Projeleri Birimi (BAP) tarafından desteklenen 2024/045 numaralı proje kapsamında yürütülmüş olup, ilgili projenin bir çıktısıdır.

Analysis of the Effects of Geomagnetic Events on the Thermal Capacity and Performance of Synchronous Generators

Öz

In this study, the effects of geomagnetically induced currents (GICs), which occur in power transmission systems as a result of geomagnetic storms, on the performance parameters of synchronous generators were investigated. Parametric analyses were carried out under different grounding resistance values and GIC levels using a test system developed in the MATLAB/Simulink environment. The analyses revealed that GICs cause magnetic saturation in generator step-up transformers (GSUs), leading to increased harmonic components of magnetizing currents and elevated reactive power demand. This condition may result in thermal and structural issues such as rotor overheating, insulation degradation in field windings, and increased losses in synchronous generators. Furthermore, it was observed that low grounding resistance significantly amplifies harmonic distortion and reactive power demand, whereas higher resistance values help mitigate these effects. Additionally, instead of time-consuming detailed simulations, mathematical models were developed using the Response Surface Methodology (RSM) to enable fast, reliable, and highly accurate predictions of GIC impacts. The results demonstrated that key performance parameters such as equivalent negative sequence current (I2eq), total harmonic distortion of generator current (THDIG), and reactive power demand (Q1) can be statistically modeled with respect to GIC levels and grounding resistance.

Anahtar Kelimeler

• Geomagnetically induced currents
• synchronous generators
• generator step-up transformers
• thermal capacity
• response surface methodology.

Destekleyen Kurum

Balikesir University Scientific Research Projects Unit (BAP)

Proje Numarası

2024/045

Teşekkür

This study was carried out within the scope of project number 2024/045 supported by Balıkesir University Scientific Research Projects Unit (BAP) and is an output of the related project.

Kaynakça

1. S. Shetye and T. J. Overbye, “Modeling and analysis of GMD effects on power systems: An overview of the impact on large-scale power systems,” IEEE Electr. Mag., vol. 3, no. 4, pp. 13–21, 2015.
2. F. R. Faxvog et al., “Power grid protection against geomagnetic disturbances (GMD),” in Proc. IEEE Electr. Power Energy Conf. (EPEC), Halifax, NS, Canada, 2013, pp. 1–13.
3. P. R. Price, “Geomagnetically induced current effects on transformers,” IEEE Trans. Power Del., vol. 17, no. 4, pp. 1002–1008, 2002.
4. R. Langella, A. Testa, and A. E. Emanuel, “On the effects of subsynchronous interharmonic voltages on power transformers: Three-phase units,” IEEE Trans. Power Del., vol. 23, no. 4, pp. 2461–2471, 2008.
5. A. Rezaei-Zare, L. Marti, A. Narang, and A. Yan, “Analysis of three-phase transformer response due to GIC using an advanced duality-based model,” IEEE Trans. Power Del., vol. 31, no. 5, pp. 2342–2350, 2016.
6. M. Lahtinen and J. Elovaara, “GIC occurrences and GIC test for 400 kV system transformer,” IEEE Trans. Power Del., vol. 17, no. 2, pp. 555–561, 2002.
7. A. Rezaei-Zare, “Behavior of single-phase transformers under geomagnetically induced current conditions,” IEEE Trans. Power Del., vol. 29, no. 2, pp. 916–925, 2014.
8. S. Canturk, M. E. Balci, M. H. Hocaoglu, and A. K. Koseoglu, “Investigation of the effects of DC bias on single-phase shell type transformers using frequency-dependent reluctance-based model,” IEEE Trans. Magn., vol. 57, no. 9, pp. 1–10, 2021.

9. S. Canturk, M. E. Balci, M. H. Hocaoglu, and A. K. Koseoglu, “Performance analysis of three-phase five-leg transformers under DC bias using a new frequency-dependent reluctance-based model,” IET Gener. Transm. Distrib., vol. 16, no. 12, pp. 2455–2465, 2022.
10. R. Girgis and K. Vedante, “Effects of GIC on power transformers and power systems,” in Proc. IEEE PES T&D Conf. Expo., Orlando, FL, USA, 2012.
11. O. Samuelsson, “Geomagnetic disturbances and their impact on power systems,” Industrial Electrical Engineering and Automation Status Report, Lund University, 2013.
12. V. D. Albertson et al., “Geomagnetic disturbance effects on power systems. Discussion,” IEEE Trans. Power Del., vol. 8, no. 3, pp. 1206–1216, 1993.
13. W. B. Gish, W. E. Feero, and G. D. Rockefeller, “Rotor heating effects from geomagnetic induced currents,” IEEE Trans. Power Del., vol. 9, no. 2, pp. 712–719, 1994.
14. A. Rezaei-Zare and L. Marti, “Generator thermal stress during a geomagnetic disturbance,” in Proc. IEEE PES General Meeting, Vancouver, BC, Canada, 2013, pp. 1–5.
15. P. Jankee, D. T. O. Oyedokun, and H. Chisepo, “Harmonic sequences affecting synchronous generator response to GIC,” in Proc. IEEE PES/IAS PowerAfrica, Kigali, Rwanda, 2022, pp. 1–5.
16. P. Jankee, D. T. O. Oyedokun, and H. K. Chisepo, “Dynamic response of power systems with real GICs: Impact on generator excitation control,” IEEE Trans. Power Del., vol. 37, no. 6, pp. 4911–4922, 2022.
17. P. Jankee, D. T. O. Oyedokun, and H. Chisepo, “Synchronous generator modelling and excitation voltage control for GIC studies,” in Proc. 13th IEEE PES APPEEC, Thiruvananthapuram, India, 2021, pp. 1–6.
18. A. H. Etemadi and A. Rezaei-Zare, “Optimal placement of GIC blocking devices for geomagnetic disturbance mitigation,” IEEE Trans. Power Syst., vol. 29, no. 6, pp. 2753–2762, 2014.
19. K. Zheng et al., “Effects of system characteristics on geomagnetically induced currents,” IEEE Trans. Power Del., vol. 29, no. 2, pp. 890–898, 2014.
20. Z. M. K. Abda, N. F. Ab Aziz, M. Z. Ab Kadir, and Z. A. Rhazali, “A review of geomagnetically induced current effects on electrical power system: Principles and theory,” IEEE Access, vol. 8, pp. 200237–200258, 2020.
21. M. Kazerooni, H. Zhu, and T. J. Overbye, “Improved modeling of geomagnetically induced currents utilizing derivation techniques for substation grounding resistance,” IEEE Trans. Power Del., vol. 32, no. 5, pp. 2320–2328, 2017.
22. U. Bui, T. J. Overbye, K. Shetye, H. Zhu, and J. Weber, “Geomagnetically induced current sensitivity to assumed substation grounding resistance,” in Proc. North Amer. Power Symp. (NAPS), Manhattan, KS, USA, 2013, pp. 1–6.
23. IEEE Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Ground System Part 1: Normal Measurements, IEEE Std 81-1983, pp. 1–44, Mar. 11, 1983.
24. IEEE Guide for Measurement of Impedance and Safety Characteristics of Large, Extended or Interconnected Grounding Systems, IEEE Std 81.2-1991, pp. 1–112, Jun. 25, 1992.
25. IEEE Guide for Safety in AC Substation Grounding, IEEE Std 80-2013 (Rev. IEEE Std 80-2000/Incl. Corrigendum 1-2015), pp. 1–226, May 15, 2015.
26. A. L. Kinyon, “Earth resistivity measurements for grounding grids,” Trans. Amer. Inst. Elect. Eng. Power Appar. Syst., vol. 80, no. 3, pp. 795–799, 1961.
27. Electric Power Research Institute (EPRI), “3002017707 – Assessment guide: Geomagnetic disturbance harmonic impacts and asset withstand capabilities,” Tech. Update. [Online]. Available: https://www.epri.com/research/products/000000003002017707
28. IEEE Standard for Salient-Pole 50 Hz and 60 Hz Synchronous Generators and Generator/Motors for Hydraulic Turbine Applications Rated 5 MVA and Above, IEEE Std C50.12-2005, pp. 1–45, Feb. 15, 2006.
29. IEEE Standard for Cylindrical-Rotor 50 Hz and 60 Hz Synchronous Generators Rated 10 MVA and Above, IEEE Std C50.13-2014, pp. 1–63, May 9, 2014.
30. D. H. Boteler and R. J. Pirjola, “Modeling geomagnetically induced currents,” Space Weather, vol. 15, no. 1, pp. 258–276, 2017.
31. D. H. Boteler, R. Pirjola, C. Blais, and A. Foss, “Development of a GIC simulator,” in Proc. IEEE PES Gen. Meeting Conf. Expo., National Harbor, MD, USA, 2014.
32. MathWorks, “Model the dynamics of three-phase round-rotor or salient-pole synchronous machine – Simulink,” Nov. 2024. [Online]. Available: https://www.mathworks.com/help/sps/powersys/ref/synchronousmachinesifundamental.html
33. IEEE Guide for Synchronous Generator Modeling Practices and Applications in Power System Stability Analyses, IEEE, vol. 2, Nov. 2002.
34. Typhoon HIL, “Typhoon HIL software manual.” [Online]. Available: https://www.typhoon-hil.com/documentation/typhoon-hil-software-manual/References/ieee_type1_exciter.html
35. D. C. Montgomery, Design and Analysis of Experiments, 9th ed. Hoboken, NJ, USA: Wiley, 2017.
36. A. Bonner, et al., “Modeling and simulation of the propagation of harmonics in electric power networks,” IEEE Trans. Power Del., vol. 11, no. 1, pp. 452–465, 1996.