Transient stability control by means of under-frequency load shedding and a hybrid control scheme

  • P. F. Le Roux
  • R.C. Bansal
Keywords: Transient Stability, COI-referred reference frame index, Under Frequency Load Shedding, Hybrid Control Scheme


An electrical network constantly faces unforeseen events such as faults on lines, loss of load and loss of generation. Under-frequency load shedding and generator tripping are traditional methods used to stabilise a network when a transient fault occurs. These methods will prevent any network instability by shedding load or tripping the most critical generator at a calculated time when required. By executing these methods, the network can be stabilised in terms of balancing the generation and the load of a power system. A hybrid control scheme is proposed where the traditional methods are combined to reduce the stress levels exerted on the network and to minimise the load to be shed.


Kundur, P., Balu, N. J. and Lauby, M. G. 1994. Power system stability and control. 7: McGraw-hill New York.

Pavella, M., Ernst, D. and Ruiz-Vega, D. 2000, Transient stability of power systems: a unified approach to assessment and control: Springer Science and Business Media.

Ning, J. A., Liu, X. and Venkatasubramanian, V. M. 2013. Distributed real-time stability monitoring algorithms using synchrophasors. Bulk Power System Dynamics and Control-IX; Optimization, Security and Control of the Emerging Power Grid, Rethymnon, Greece 1–5.

Brown, H., Happ, H., Person, C. and Young, C. 1965. Transient stability solution by an impedance matrix method. IEEE Transactions on Power Apparatus and Systems 84: 1204–1214.

Sherwood, M., Hu, D. and Venkatasubramanian, V. M. 2007. Real-time detection of angle instability using synchrophasors and action principle. in Bulk Power System Dynamics and Control-VII. Revitalizing Operational Reliability, IREP Symposium, Charleston, SC, USA 1–11.

Wang, Z., Aravnthan, V. and Makram, E. B. 2011. Generator cluster transient stability assessment using catastrophe theory. in 10th International Conference, Environment and Electrical Engineering (EEEIC), Rome, Italy 1–4.

Zhou, D. Q., Annakkage, U. and Rajapakse, A. D. 2010. Online monitoring of voltage stability margin using an artificial neural network. IEEE Transactions on Power Systems 25: 1566–1574.

Yan, P., Sekar, A. and Rajan, P. 2000. Pattern recognition techniques applied to the classification of swing curves generated in a power system transient stability study. Proceedings of the IEEE Southeastcon 493–496.

Chang, C., Srinivasan, D. and Liew, A. 1994. A hybrid model for transient stability evaluation of interconnected longitudinal power systems using neural network/pattern recognition approach. IEEE Transactions on Power Systems 9: 85–92.

Glavic, M. and Van Cutsem, T. 2011. A short survey of methods for voltage instability detection. IEEE Power and Energy Society General Meeting 1–8.

Hu, D. and Venkatasubramanian, V. 2007. New wide-area algorithms for detection and mitigation of angle instability using synchrophasors. IEEE Power Engineering Society General Meeting, Tampa, FL, USA: 1–8.

Hashim, H., Zulkepali, M., Omar, Y., Ismail, N., Abidin, I. and Yusof, S. 2010. An analysis of transient stability using center-of-inertia: angle and speed. IEEE International Conference on Power and Energy (PECon), Kuala Lumpur, Malaysia 402–407.

Abdul Wahab, N. I. and Mohamed, A. 2012. Area-based center-of-inertia-referred rotor angle index for transient stability assessment and control of power systems. Abstract and Applied Analysis: 1–23.

Zhang, C., Wang, P. and Fang, Y. 2013. Emergency control strategy based on frequency and voltage stability. Power System Protection and Control 41: 149–155.

Zhang, M., Bi, S., Liu, H. and Xue, C. 2011. Review of frequency stability for islanded power system. Power System Protection and Control 39: 149–154.

Xiong, F., Zhou, Z. and Zhou, Q., 2005. Study of under frequency load shedding scheme based on load frequency characteristics. Proceedings of the CSEE, 19: 1–9.

Zhang, Z., Wang, Z. and Fang, P. 2014. Study on emergency load shedding based on frequency and voltage stability. International Journal of Control & Automation 7: 119–130.

Terzija, V. V. 2006. Adaptive underfrequency load shedding based on the magnitude of the disturbance estimation. IEEE Transactions on Power Systems 21, 1260–1266.

Seyedi, H. and Sanaye-Pasand, M. 2009. New centralised adaptive load-shedding algorithms to mitigate power system blackouts. IET Generation, Transmission & Distribution 3: 99–114.

Dong, Y. and Pota, H. 1991. Fast transient stability assessment using large step-size numerical integration. IEE Proceedings C-Generation, Transmission and Distribution 138: 377–383.

Dong, Y. and Pota, H. R. 1991. Determination of the first swing stability by solving simultaneous differential and algebraic equation set without system reduction. IEEE Region 10 International Conference on EC3-Energy, Computer, Communication and Control Systems, New Delhi, India 1: 382–385.

Fouad, A., Vittal, V., Ni, X., Pota, H., Nodehi, K., Zein-Eldin, H. M., Vasahedi, E. and Kim, J. 1989. Direct transient stability assessment with excitation control. IEEE Transactions on Power Systems, 4: 75–82.

Yusof, S., Rogers, G. and Alden, R. 1993. Slow coherency based network partitioning including load buses. IEEE Transactions on Power Systems 8: 1375–1382.

Xie, D., He, H., Chang, X. and Yao, X. 2010. An approach to design power system under frequency load shedding scheme taking coherent area and global optimization into account. Power System Technology 6: 106–112.
  • Abstract 20
  • PDF 11
Views and downloads are with effect from 11 January 2018