Voltage Profile Improvement in Renewable-Integrated Distribution Grids using the Voltage Deviation Index for Optimal DG Placement

Chinedu Chigozie Nwobu¹, Obinna Kingsley Obi², Abigail Chidimma Odigbo³

^1,2,3 Nnamdi Azikiwe University, Awka, Nigeria. 

Abstract

This paper investigates voltage profile improvement in an 11 kV/0.415 kV distribution network using the Voltage Deviation Index (VDI) as the objective criterion for optimal placement of distributed generation (DG). A 33-bus representation of the Enugu distribution network is modeled and analyzed in ETAP. Baseline load flow results identify the weakest buses by VDI. A renewable-integrated DG (PV + BESS + synchronous generator units in the modeled hybrid mix) is placed at the bus with maximum VDI (Bus512), and the system is reanalyzed. Results show a substantial reduction in the maximum VDI from 2.8636% (baseline) to 0.0091% (with DG at Bus512), corresponding to a 99.68% improvement in maximum deviation. The study demonstrates that a simple, direct power quality metric like VDI can be an effective and computationally lightweight objective for DG siting to rapidly improve voltage profiles in distribution networks with high renewable penetration.    

Keywords: Voltage profile improvement, Voltage Deviation Index (VDI), Distributed Generation (DG), Optimal placement, Renewable energy, Power quality, Distribution grids, ETAP

References

1. Adegoke, S.A., Sun, Y., Adegoke, A.S. and Ojeniyi, D. (2024) ‘Optimal placement of distributed generation to minimize power loss and improve voltage stability’, Heliyon, 10(21), e39298. https://doi.org/10.1016/j.heliyon.2024.e39298
2. Alturki, M. and Marouani, I. (2024) ‘Simulation tools for FACTS devices optimization problems in electrical power systems.’, AIMS Energy, 12(6), pp. 1113–1172. https://doi.org/10.3934/energy.2024053
3. Anthony, K. and Arunachalam, V. (2025) ‘Voltage stability monitoring and improvement in a renewable energy dominated deregulated power system: a review’, e-Prime – Advances in Electrical Engineering Electronics and Energy, 11, 100893. https://doi.org/10.1016/j.prime.2024.100893
4. Danish, M.S.S., Senjyu, T., Danish, S.M.S., Sabory, N.R., et al. (2019) ‘A recap of voltage stability indices in the past three decades’, Energies, 12(8), 1544. https://doi.org/10.3390/en12081544
5. Haider, W., Hassan, S.J.U., Mehdi, A., Hussain, A., et al. (2021) ‘Voltage profile enhancement and loss minimization using optimal placement and sizing of distributed generation in reconfigured network’, Machines, 9(1), 20. https://doi.org/10.3390/machines9010020
6. Ismail, B., Wahab, N.I.A., Othman, M.L., Radzi, M.A.M., et al. (2020) ‘A comprehensive review on optimal location and sizing of reactive power compensation using hybrid-based approaches for power loss reduction, voltage stability improvement, voltage profile enhancement and loadability enhancement’, IEEE Access, 8, pp. 222733–222765. https://doi.org/10.1109/access.2020.3043297
7. Justin, U., Salami, K.O., Oluka, L.O. and Ejiofor, O.S. (2021) ‘Incidences of voltage collapse in the Nigerian power system: data and analysis’, Technology Reports of Kansai University, 63(3), pp. 7421–7438.
8. Khare, C.J., Verma, H.K. and Khare, V. (2021) ‘Optimal power generation and power flow control using artificial intelligence techniques’, In: Renewable Energy Systems; Azar, A.T. and Kamal, N.A. Academic Press, pp. 607–631. https://doi.org/10.1016/b978-0-12-820004-9.00028-0
9. Mehtre, V.V. and Dubey, A. (2024) ‘A case study for optimization of power system load flow analysis using ETAP software’, World Journal of Advanced Engineering Technology and Sciences, 11(2), pp. 476–492. https://doi.org/10.30574/wjaets.2024.11.2.0121
10. Mirza, Z. and Jain, H. (2025) ‘From challenges to solutions: Review and analysis of grid-supportive technologies in sustainable power systems’, Applied Energy, 403, 127111. https://doi.org/10.1016/j.apenergy.2025.127111
11. Saxena, V., Manna, S., Rajput, S.K., Kumar, P., et al. (2024) ‘Navigating the complexities of distributed generation: Integration, challenges, and solutions’, Energy Reports, 12, pp. 3302–3322. https://doi.org/10.1016/j.egyr.2024.09.017
12. Vidyasagar, S., Vijayakumar, K., Sattianadan, D. and Fernandez, S.G. (2016) ‘Optimal placement of DG based on voltage stability index and voltage deviation index’, Indian Journal of Science and Technology, 9(38), pp. 1-9. https://doi.org/10.17485/ijst/2016/v9i38/101930