Incorporating bus-bar switching actions into AC optimal power flow to ovoid over-current status

Document Type : Article


1 Department of Electrical and Computer Engineering, Semnan University, Semnan, P.O. Box 35195-363, Iran

2 Department of Electrical and Computer Engineering, Semnan University, Semnan, P.O. Box 35195-363, Iran.


This paper presents a new AC optimal power flow (AC OPF) model for sub-transmission networks. This model, which consists of sub-transmission and distribution bus-bar switching actions, can avoid undesirable over-current (OC) status and subsequent actions of OC relays. The proposed AC OPF optimizes the bus-bar switching actions along with optimizing sub-transmission control actions. Also, to consider the impact of OC relays’ actions in the proposed AC OPF, the cost of load shedding caused by these relay actions is included in the objective function and is minimized along with the sub-transmission operation cost. The bus-bar switching actions are modeled using binary decision variables. Therefore, the proposed AC OPF model is formulated as a Mixed Integer Non-linear Programming (MINLP) optimization problem. The effectiveness of the proposed model is illustrated on a real-world sub-transmission network of Iran’s power system.


1. Capitanescu, F. "Critical review of recent advances and further developments needed in AC optimal power  flow", Electr. Power Syst. Res., 136, pp. 57-68 (2016).
2. Abdi, H., Beigvand, S.D., and Scala, M.La. "A review of optimal power flow studies applied to smart grids and microgrids", Renew. Sustain. Energy Rev., 71, pp. 742-766 (2017).
3. Maskar, M.B., Thorat, A.R., and Korachgaon, I. "A review on optimal power flow problem and solution methodologies", 2017 Int. Conf. Data Manag. Anal. Innov. ICDMAI 2017, pp. 64-70 (2017).
4. Pegado, R., Naupari, Z., Molina, Y., et al. "Radial distribution network reconfiguration for power losses reduction based on improved selective BPSO", Electr. Power Syst. Res., 169, pp. 206-213 (2019).
5. Murty, V.V.V.S.N. and Sharma, A.K. "Optimal coordinatecontrol of OLTC, DG, D-STATCOM, and reconfiguration in distribution system for voltage control and loss minimization", Int. Trans. Electr. Energy Syst., 29(3), pp. 1-27 (2019).
6. Gholami, K., Karimi, S., and Dehnavi, E. "Optimal unified power quality conditioner placement and sizing in distribution systems considering network reconfiguration", Int. J. Numer. Model. Electron. Networks, Devices Fields, 32(1), pp. 1-17 (2019).
7. Home-Ortiz, J.M., Vargas, R., Macedo, L.H., et al. "Joint reconfiguration of feeders and allocation of capacitor banks in radial distribution systems considering voltage-dependent models", Int. J. Electr. Power Energy Syst., 107, pp. 298-310 (2019).
8. Salkuti, S.R. "Congestion management using optimal transmission switching", IEEE Syst. J., 12(4), pp. 3555-3564 (2018).
9. Xiao, R., Xiang, Y., Wang, L., et al. "Power system reliability evaluation incorporating dynamic thermal rating and network topology optimization", IEEE Trans. Power Syst., 33(6), pp. 6000-6012 (2018).
10. Jalali, M., Zare, K., and Hagh, M.T. "A multistage MINLP-based model for sub-transmission system expansion planning considering the placement of DG units", Int. J. Electr. Power Energy Syst., 63, pp. 8-16 (2014).
11. Rad, H.K. and Moravej, Z. "Sub-transmission substation expansion planning based on bacterial foraging optimization algorithm", J. AI Data Min., 5(1), pp. 11-20 (2017).
12. Abedi, M.H., Hosseini, H., and Jalilvand, A.  Subtransmission substation expansion planning considering load center uncertainties of size and location", Int. J. Electr. Power Energy Syst., 109, pp. 413-422 (2019).
13. Dehghanian, P. and Kezunovic, M. "Impact assessment of transmission line switching on system reliability performance", 2015 18th Int. Conf. Intell. Syst. Appl. to Power Syst. ISAP 2015 (2015).
14. Tavakkoli, M.A. and Amjady, N. "A new AC OPF tool for sub-transmission networks considering distribution switching actions and load-transferring capability", Int. Trans. Electr. Energy Syst., 29(8), pp. 1-17 (2019).
15. Feng, J., Zhang, J.H., and Liu, R.X. "Analysis of surge current due to closing loop in distribution network", In Proc. 8th Int. Conf. Adv. Power Syst. Control Oper. Manag., Hong Kong, China, pp. 1-5 (2009).
16. Yin, Q., Ding, R., Zhao, Y., et al. "The feasibility research on distribution network closed loop based on the load transfer model", World J. Eng. Technol., 05(04), pp. 12-20 (2017).
17. Li, Z., Chen, L., Yang, W., et al. "Using hybrid type SFCL to limit the surge current caused by closing loop operation in distribution system", Appl. Mech. Mater., 556-562, pp. 1647-1651 (2014).
18. Rahmani, S. and Amjady, N. "A new optimal power flow approach for wind energy integrated power systems", Energy, 134, pp. 349-359 (2017).
19. Sharifzadeh, H., Amjady, N., and Zareipour, H. "Multi-period stochastic security-constrained OPF considering the uncertainty sources of wind power, load demand and equipment unavailability", Electr. Power Syst. Res., 146, pp. 33-42 (2017).
20. Attarha, A., Amjady, N., and Conejo, A.J. "Adaptive robust AC optimal power flow considering load and wind power uncertainties", Int. J. Electr. Power Energy Syst., 96, pp. 132-142 (2018).
21. Wu, X., Conejo, A.J., and Amjady, N. "Robust security constrained ACOPF via conic programming: Identifying the worst contingencies", IEEE Trans. Power Syst., 33(6), pp. 5884-5891 (2018).
22. GAMS (2018): Generalized Algebraic Modelling System. [online], Available: (n.d.).
23. Ahmadigorji, M. and Amjady, N. "A multiyear DGincorporated framework for expansion planning of distribution networks using binary chaotic shark smell optimization algorithm", Energy, 102, pp. 199-215 (2016).
24. Attarha, A. and Amjady, N. "Solution of security constrained optimal power flow for large-scale power systems by convex transformation techniques and Taylor series", IET Gener. Transm. Distrib., 10(4), pp. 889-896 (2016).
25. Wu, T., Zhang, Y.J., and Tang, X. "A VSC-based BESS model for multi-objective OPF using mixed integer SOCP", IEEE Trans. Power Syst., 34(4), pp. 2541-2552 (2019).
26. Erseghe, T. and Tomasin, S. "Power flow optimization for smart microgrids by SDP relaxation on linear networks", IEEE Trans. Smart Grid, 4(2), pp. 751-762 (2013).
27. Bynum, M., Castillo, A., Watson, J.P., et al. "Tightening McCormick relaxations toward global solution of the ACOPF problem", IEEE Trans. Power Syst., 34(1), pp. 814-817 (2019).
28. Pareek, P. and Verma, A. "Linear OPF with linearization of quadratic branch flow limits", 2018 IEEMA Eng. Infin. Conf. ETechNxT 2018, pp. 1-6 (2018).
29. Miao, Z., Fan, L., Aghamolki, H.G., et al. "Least squares estimation based SDP cuts for SOCP relaxation of AC OPF", IEEE Trans. Automat. Contr., 63(1), pp. 241-248 (2018).