Load flow studies play a critical role in the analysis of power systems.
They enable the computation of voltage, current, and power flows in a power
system. They provide valuable insights into the steady-state performance of the
power system under different operating conditions. Choosing a slack bus is a
vital step in conducting load flow simulations. A slack bus is a PV bus that
includes a generator and is used to balance real and reactive power during load
flow studies. Many studies have been conducted on the selection of slack buses
in load flow analysis. However, varied conclusions regarding the impact on
system losses and power flows were obtained during these studies. Therefore,
using the IEEE-14 bus test system, this study investigated the effects of slack
bus selection in strong and weak grids by alternating slack buses among PV
buses and observing the effects on bus voltage magnitude, bus voltage phase angle, total power flows, and active and
reactive power losses. The study noted that the effect of slack bus selection
on these system quantities is contingent upon the voltage stability of the
grid. Whereas in a robust grid, system losses and power flows remained constant
irrespective of the choice of slack bus, a weak grid experienced some
variations in these system quantities under similar circumstances. The
simulation results led to the conclusion that, to a large extent, the voltage
stability of the grid plays a significant role in determining the degree to
which slack bus selection affects system losses and other quantities in load
flow studies.
References
[1]
Kundur, P., Balu, N.J. and Lauby, M.G. (1994) Power System Stability and Control. The EPRI Power System Engineering Series. McGraw-Hill, New York.
[2]
Sabati, A., Basaran, K., Bayindir, R., Sanjeevikumar, P., Siano, P. and Leonowicz, Z. (2017) Investigating the Effects of Selecting Different Slack Bus on Power Systems. 2017 IEEE International Conference on Environment and Electrical Engineering and 2017 IEEE Industrial and Commercial Power Systems Europe (EEEIC/I&CPS Europe), Milan, 6-9 June 2017, 1-6. https://doi.org/10.1109/EEEIC.2017.7977880
[3]
Ramar, S. and Kuruseelan, S. (2013) Power System Analysis. PHI Learning Private Limited, New Delhi.
[4]
Chakrabarti, A. (2010) An Introduction to Reactive Power Control and Voltage Stability in Power Transmission Systems. PHI Learning Private Limited, New Delhi.
[5]
Samuel, I., Marian, N. and Abdulkareem, A. (2014) Investigating the Selection of a Suitable Slack Bus: A Case Study of the Multi-Generating Stations of the Nigerian 330-KV Power System Network. International Journal of Electrical Electronic Engineering Studies, 2, 1-12.
[6]
Vazquez, C., Pérez-Arriaga, I. and Olmos, L. (2012) On the Selection of the Slack Bus in Mechanisms for Transmission Network Cost Allocation That Are Based on Network Utilization. https://ssrn.com/abstract=4237409
[7]
Exposito, A.G., Ramos, J.L.M. and Santos, J.R. (2004) Slack Bus Selection to Minimize the System Power Imbalance in Load-Flow Studies. IEEE Transactions on Power Systems, 19, 987-995. https://doi.org/10.1109/TPWRS.2004.825871
[8]
Moses, P.M. and Odero, N.A. (2012) Distributed Slack Bus Model for a Wind-Based Distributed Generation Using Combined Participation Factors. International Journal of Emerging Technology and Advanced Engineering, 2, 459-469.
[9]
Kothari, D.P. and Nagrath, I.J. (2007) Power System Engineering. 2nd Edition, Tata McGraw-Hill, New Delhi.
[10]
Shen, Z., Wei, Z., Sun, G. and Chen, S. (2019) Representing ZIP Loads in Convex Relaxations of Optimal Power Flow Problems. International Journal of Electrical Power & Energy Systems, 110, 372-385. https://doi.org/10.1016/j.ijepes.2019.03.011
[11]
Roy, N.K., Hossain, M.J. and Pota, H.R. (2011) Effects of Load Modeling in Power Distribution System with Distributed Wind Generation. 2011 21st Australasian Universities Power Engineering Conference, AUPEC 2011.
[12]
Wu, A. and Ni, B.S. (2016) Line Loss Analysis and Calculation of Electric Power Systems. China Electric Power Press, Beijing. https://doi.org/10.1002/9781118867273
[13]
Huang, Z., Bao, L. and Xu, W. (2007) A Method to Measure QV Curves and Its Applications in Power Systems. International Journal of Electrical Power & Energy Systems, 29, 147-154. https://doi.org/10.1016/j.ijepes.2006.06.003
[14]
Mahmood, F., et al. (2017) Weakest Location Exploration in IEEE-14 Bus System for Voltage Stability Improvement Using STATCOM, Synchronous Condenser and Static Capacitor. 2017 International Conference on Electrical, Computer and Communication Engineering (ECCE), Cox’s Bazar, 16-18 February 2017, 623-629. https://doi.org/10.1109/ECACE.2017.7912980
[15]
Aziz, T., Saha, T.K. and Mithulananthan, N. (2010) Distributed Generators Placement for Loadability Enhancement Based on Reactive Power Margin. 2010 Conference Proceedings IPEC, Singapore, 27-29 October 2010, 740-745. https://doi.org/10.1109/IPECON.2010.5697023
[16]
Muhammed, A.O. and Rawa, M. (2020) A Systematic PVQV-Curves Approach for Investigating the Impact of Solar Photovoltaic-Generator in Power System Using PowerWorld Simulator. Energies, 13, Article 2662. https://doi.org/10.3390/en13102662
[17]
ILLINOIS, Information Trust Institute and Grainger College of Engineering (1962) IEEE 14-Bus System. https://icseg.iti.illinois.edu/ieee-14-bus-system/
[18]
(1962) Power Systems Test Case Archive. https://labs.ece.uw.edu/pstca/pf14/pg_tca14bus.htm
