Modeling and Simulation of Under -Frequency Relay for Generator Protection

  • Mohsin Ali Koondhar Department of Engineering, Quaid-e-Awam University of Engineering, Science & Technology Nawabshah
  • Ahsan Ali Memon Department of Electrical Engineering, Quaid-e-Awam University of Engineering, Science & Technology Nawabshah
  • Imdad Ali Memon Department of Mechanical Engineering, Quaid-e-Awam University of Engineering, Science & Technology Nawabshah
  • Sadam Hussain Rajput Department of Mechanical Engineering, Quaid-e-Awam University of Engineering, Science & Technology Nawabshah
  • Masood Ali Koondhar Department of Electronic Engineering, Quaid-e-Awam University of Engineering, Science & Technology Nawabshah
  • Irfan Ali Channa Department of Automation, Beijing University of Chemical Technology, Beijing China


Power systems are undergoing structural changes induced by the combination of the operation of microgrids and distributed generation units. This transfiguration has impersonated new challenges in well-established power system practices, coordination of protection systems and especially on the design. Same time, technological improvements in protective equipment have set up the basis for the development of digital frequency relays which enable an alternate approach to standard protection schemes. It is necessary for the power system to operates, regulates and manages ancillary services more efficiently to maintain the reliability of the system. The power system is continually laying unexpected contingencies which cause inequality between load demand and generated power. Such uncertainties cause the disturbance in the power system frequency. The only way to maintain power system frequency by balancing load and generation. In this paper, we have designed the under frequency relay model in Matlab simulink. We have noticed that when the load on the system is increased, the designed model shed the extra load and are modeled through under frequency relay by comparing the frequency responses of the power system.  


Download data is not yet available.


[1] M. M. Aman et al., “Modeling and simulation of digital negative sequence relay for unbalanced protection of generator”, IEEE International Power Engineering and Optimization Conference Melaka, Malaysia, pp. 72-77, 2012.
[2] C. S. Chen, Y. L. Ke, and C. T. Hsu, “Protective relay setting of the tie line tripping and load shedding for the industrial power system”, IEEE Transactions on Industry Applications, vol. 36, no. 5, pp. 1226- 1234, 2000.
[3] B. Khaki, and S. M. Kouhsari, “Proper setting of under frequency load shedding relays in industrial plants”, In 9th IEEE International Conference on Environment and Electrical Engineering, pp. 198-201, 2010.
[4] U. Rudez, and R. Mihalic, “Analysis of under frequency load shedding using a frequency gradient”, IEEE transactions on power delivery, vol. 26, no. 2, pp. 565-575, 2011.
[5] H. Bevrani, G. Ledwich, and J. J. Ford, “On the use of df/dt in power system emergency control”, In IEEE/PES Power Systems Conference and Exposition, pp. 1-6, 2009.
[6] U. K. Jethwa, R. K. Bansal, N. Date, R. Vaishnav, “Comprehensive Load-Shedding System”, IEEE Transactions on, Industry Applications, vol. 46, no.2, pp.740,749, 2010.
[7] B. Delfino, S. Massucco, A. Morini, P. Scalera, F. Silvestro, “Implementation and comparison of different under frequency load- shedding schemes”, Power Engineering Society Summer Meeting, vol. 1, pp. 307- 312, 2001.
[8] C. T. Hsu, “Cogeneration system ` design for a high-tech science-based industrial park”, IEEE Trans. Ind. Appl., vol. 39, no. 5, pp. 1486–1492, 2003.
[9] C. Concordia, L. H. Fink, G. Ponllikkas, “Load shedding on an isolated system”, IEEE Transactions on Power Systems, vol. 10, no.3, pp. 1467-1472, 1995.
[10] IEEE Std C37.102TM: IEEE guide for AC generator protection; 2006.
[11] de Morais, Adriano P., et al., “High- sensitivity stator fault protection for synchronous generators: A time-domain approach based on mathematical morphology”, International Journal of Electrical Power & Energy Systems, 99, pp. 419-425, 2018.
[12] M. O. Oliveira, A. S. Bretas, G. D. Ferreira, “Adaptive differential protection of three-phase power transformers based on transient signal analysis”, Int J Electr Power Energy System, 57, pp. 366–374, 2014.
[13] Y. Wang, J. Zhou, G. Wei, Z. Dong, H. Chen, “Stator winding single-phase grounding faults protective scheme based on discriminant analysis for Powerformers with selectivity”, Int J. Electr Power Energy System, 77, pp. 145–150, 2016.
[14] J. R. Jones, W. D. Kirkland, “Computer algorithm for selection of frequency relays for load shedding”, IEEE Computer Applications in Power, vol. 1, no.1, pp.21,25, 1988.
[15] P. Pinceti, “Emergency load- shedding algorithm for large industrial plants”, Control Engineering Practice, 10, pp. 175–181, 2002.
[16] D. Reimert, “Protective relaying for power generation systems”, CRC Press Taylor & Francis Group, 1–545, 2006.
[17] P. Lakra, and M. Kirar, “A comparison of Under Frequency Relay based and Frequency Response model based Load Shedding scheme”, In Annual IEEE India Conference, pp. 1-6, 2015.
How to Cite
KOONDHAR, Mohsin Ali et al. Modeling and Simulation of Under -Frequency Relay for Generator Protection. Sukkur IBA Journal of Emerging Technologies, [S.l.], v. 3, n. 2, p. 82-89, dec. 2020. ISSN 2617-3115. Available at: <>. Date accessed: 19 apr. 2021. doi: