Automatic Generation Control Design Based on Full State Vector Feedback for a Multi-Area Energy System Connected via Parallel AC/DC Lines

Authors: Gulshan Sharma

Abstract:

This article presents the design of optimal automatic generation control (AGC) based on full state feedback control for a multi-area interconnected power system. An extra high voltage AC transmission line in parallel with a high voltage DC link is considered as an area interconnection between the areas. The optimal AGC are designed and implemented in the wake of 1% load perturbation in one of the areas and the system dynamic response plots for various system states are obtained to investigate the system dynamic performance. The pattern of closed-loop eigenvalues are also determined to analyze the system stability. From the investigations carried out in the work, it is revealed that the dynamic performance of the system under consideration has an appreciable improvement when a high voltage DC line is paralleled with an extra high voltage AC line as an interconnection between the areas. The investigation of closed-loop eigenvalues reveals that the system stability is ensured in all case studies carried out with the designed optimal AGC.

Keywords: Automatic generation control, area control error, DC link, optimal AGC regulator, closed-loop eigenvalues.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1132421

References:

[1] Sanpei, M., Kakehi, A., and Takeda, H., “Application of multi-variable control for automatic frequency controller of HVDC transmission system,” IEEE Trans. Power Delivery, Vol. 9, No. 2, pp. 1063–1068, April 1994.
[2] Kumar, P., and Ibraheem, “AGC strategies-a comprehensive review,” Int. J. Power Energy Syst., Vol. 16, No. 2, pp. 107–111, 1996.
[3] Ibraheem, Kumar, P., and Khatoon, S., “Effects of parameters uncertainties of dynamics performance of an interconnected power system systems with AC/DC links,” Int. J. Power Energy Syst., Vol. 25, No. 3, pp. 196–210, 2005.
[4] Elgerd, O. I., and Fosha, C., “Optimum megawatt frequency control of multi-area electric energy systems,” IEEE Trans. Power Apparat. Syst., Vol. PAS-89, No. 4, pp. 556–563, April 1970.
[5] Willems, J. L., “Sensitivity analysis of the optimum performance of conventional load frequency control,” IEEE Trans. Power Apparat. Syst., Vol. PAS-93, No. 5, pp. 1287–1291, September/October 1974.
[6] Nanda, J., and Kaul, B. L., “Automatic generation control of an interconnected power system,” Proc. IEE, Vol. 125, No. 5, pp. 385–390, May 1978.
[7] Kothari, M. L., Satsangi, P. S., and Nanda, J., “Sampled data automatic control of interconnected reheat thermal stations consisting generation rate constraints,” IEEE Trans. Power Apparat. Syst., Vol. PAS-100, No. 5, pp. 2334–2342, May 1981.
[8] Hiyama, T., “Optimization of discrete-type load-frequency regulators considering generation rate constraints,” Proc. IEE, Vol. 129(C), pp. 285–289, November 1982.
[9] Kothari, M. L., Satsangi, P. S., and Nanda, J., “Sampled data automatic control of interconnected reheat thermal stations consisting generation rate constraints,” IEEE Trans. Power Apparat. Syst., Vol. PAS-100, No. 5, pp. 2334–2342, May 1981.
[10] Fosha, C. E., and Elgerd, O. I., “The megawatt frequency control problem: A new approach via optimal control theory,” IEEE Trans. Power Apparat. Syst., Vol. PAS-89, No. 4, pp. 563–577, April 1970.
[11] Tacker, E. C., Lee, C. C., Reddoch, T. W., Tan, T. O., and Julich, P. M., “Optimal control of interconnected electric energy systems: A new formulation,” Proc. IEEE, Vol. 60, pp. 1239–1241, October 1972.
[12] Calovic, M. S., “Linear regulator design for a load and frequency control,” IEEE Trans. Power Apparat. Syst., Vol. PAS-91, pp. 2271–2285, 1972.
[13] Feliachi, A., “Optimal decentralized load frequency control,” IEEE Trans. Power Apparat. Syst., Vol. PAS-97, No. 2, pp. 379–385, May 1987.
[14] Kothari, M. L., and Nanda, J., “Application of optimal control strategy to automatic generation control of hydro thermal system,” IEE Proc. Pt. D, Vol. 135, No. 4, pp. 268–274, July 1988.
[15] Liaw, C. M., and Chao, K. H., “On the design of an optimal automatic generation controller for an interconnected power system,” Int. J. Control, Vol. 58, pp. 113–127, 1993.
[16] Ibraheem, and Kumar, P., “Current status of the Indian power system and dynamic performance enhancement of hydro power systems with asynchronous tie lines,” Electric Power Comp. and Syst., Vol. 31, pp. 605-626, 2003.
[17] Nanda, J., Mangla, A., and Suri, S., “Some new findings on automatic generation control of an interconnected hydro thermal system with conventional controllers,” IEEE Trans. Energy Convers., Vol. 21, No. 1, pp. 187–194, March 2006.
[18] Ibraheem, Kumar, P., Hasan, N., Singh, Y., “Optimal automatic generation control of interconnected power system with asynchronous tie-lines under deregulated environment,” Electric Power Comp. and Syst., Vol. 40, pp. 1208-1228, 2012.