Research Article

GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration

Volume: 6 Number: 4 October 19, 2026

GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration

Abstract

The increasing integration of renewable energy resources, rapid load growth, and stringent reliability requirements have significantly increased the complexity of long-term transmission expansion planning. This paper proposes a Graph Neural Network-Assisted Proximal Policy Optimization (GNN-PPO) framework for multi-stage security-constrained transmission expansion planning (SC-TEP) for renewable energy integration. The proposed approach combines graph neural networks to capture network topology and operational characteristics with proximal policy optimization to determine sequential transmission investment decisions over a long-term planning horizon. The planning framework incorporates AC power flow analysis, voltage security constraints, thermal loading limits, renewable energy integration scenarios, and N−1 contingency assessment within a unified optimization environment. The methodology is validated on the South Sulawesi, West Sulawesi, and Southeast Sulawesi (SSWSSS) interconnected power system over the 2025–2034 planning horizon using projected load growth and planned generation expansion scenarios. Simulation results identify an optimal expansion strategy consisting of five transmission reinforcement projects with a total investment cost of 113 MUSD. The selected projects maintain bus voltages within the acceptable range of 0.95–1.05 pu throughout the planning horizon, with a minimum voltage of 0.9611 pu in 2034 and no voltage violations under normal operating conditions. The proposed framework also facilitates renewable energy integration while maintaining acceptable voltage performance. Overall, the results demonstrate that the integration of graph-based feature extraction and reinforcement learning provides an effective and scalable tool for security-constrained transmission expansion planning in large-scale renewable-oriented power systems.

Keywords

References

  1. Lund, H., Østergaard, P. A., Connolly, D., & Mathiesen, B. V. (2017). Smart energy and smart energy systems. Energy, 137, 556–565. https://doi.org/10.1016/j.energy.2017.05.123
  2. Tumiran, Putranto, L. M., Irnawan, R., Sarjiya, Priyanto, A., Isnandar, S., & Savitri, I. (2021). Transmission expansion planning for the optimization of renewable energy integration in the Sulawesi electricity system. Sustainability, 13(18), Article 10477. https://doi.org/10.3390/su131810477
  3. Dini, A., Azarhooshang, A., Pirouzi, S., Norouzi, M., & Lehtonen, M. (2021). Security-constrained generation and transmission expansion planning based on optimal bidding in the energy and reserve markets. Electric Power Systems Research, 193, Article 107017. https://doi.org/10.1016/j.epsr.2020.107017
  4. Silva, I. de J., Rider, M. J., Romero, R., Garcia, A. V., & Murari, C. A. (2005). Transmission network expansion planning with security constraints. IEE Proceedings - Generation, Transmission and Distribution, 152(6), 828–836. https://doi.org/10.1049/ip-gtd:20045217
  5. Hemmati, R., Hooshmand, R. A., & Khodabakhshian, A. (2013). Comprehensive review of generation and transmission expansion planning. IET Generation, Transmission & Distribution, 7(9), 955–964. https://doi.org/10.1049/iet-gtd.2013.0031
  6. Ndlela, N. W., Moloi, K., & Kabeya, M. (2024). Comprehensive analysis of approaches for transmission network expansion planning. IEEE Access, 12, 195778–195815. https://doi.org/10.1109/access.2024.3519180
  7. Ghazal, H. M., & Khan, U. A. (2026). A comprehensive review of modern transmission expansion planning. Energy Reports, 15, Article 109313. https://doi.org/10.1016/j.egyr.2026.109313
  8. Latorre, G., Cruz, R. D., Areiza, J. M., & Villegas, A. (2003). Classification of publications and models on transmission expansion planning. IEEE Transactions on Power Systems, 18(2), 938–946. https://doi.org/10.1109/tpwrs.2003.811168

Details

Primary Language

English

Subjects

Electrical Energy Transmission, Networks and Systems, Electrical Energy Generation (Incl. Renewables, Excl. Photovoltaics)

Journal Section

Research Article

Publication Date

October 19, 2026

Submission Date

July 10, 2026

Acceptance Date

October 12, 2026

Published in Issue

Year 2026 Volume: 6 Number: 4

APA
Kitta, I., Bustanuddin, I. A., & Achmad, A. (2026). GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration. Engineering Perspective, 6(4), 611-623. https://doi.org/10.64808/engineeringperspective.1991354
AMA
1.Kitta I, Bustanuddin IA, Achmad A. GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration. engineeringperspective. 2026;6(4):611-623. doi:10.64808/engineeringperspective.1991354
Chicago
Kitta, Ikhlas, Ian Adrian Bustanuddin, and Andini Achmad. 2026. “GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration”. Engineering Perspective 6 (4): 611-23. https://doi.org/10.64808/engineeringperspective.1991354.
EndNote
Kitta I, Bustanuddin IA, Achmad A (October 1, 2026) GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration. Engineering Perspective 6 4 611–623.
IEEE
[1]I. Kitta, I. A. Bustanuddin, and A. Achmad, “GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration”, engineeringperspective, vol. 6, no. 4, pp. 611–623, Oct. 2026, doi: 10.64808/engineeringperspective.1991354.
ISNAD
Kitta, Ikhlas - Bustanuddin, Ian Adrian - Achmad, Andini. “GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration”. Engineering Perspective 6/4 (October 1, 2026): 611-623. https://doi.org/10.64808/engineeringperspective.1991354.
JAMA
1.Kitta I, Bustanuddin IA, Achmad A. GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration. engineeringperspective. 2026;6:611–623.
MLA
Kitta, Ikhlas, et al. “GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration”. Engineering Perspective, vol. 6, no. 4, Oct. 2026, pp. 611-23, doi:10.64808/engineeringperspective.1991354.
Vancouver
1.Ikhlas Kitta, Ian Adrian Bustanuddin, Andini Achmad. GNN-PPO-Based Multi-Stage Security-Constrained Transmission Expansion Planning for Renewable Energy Integration. engineeringperspective. 2026 Oct. 1;6(4):611-23. doi:10.64808/engineeringperspective.1991354

download?token=eyJhdXRoX3JvbGVzIjpbXSwiZW5kcG9pbnQiOiJqb3VybmFsIiwib3JpZ2luYWxuYW1lIjoiQ2l0ZVNjb3JlMjAyNV9FbmdpbmVlcmluZ19QZXJzcGVjdC5wbmciLCJwYXRoIjoiMjk0YS81N2EyLzlmYzcvNmEyMDA1NTk1OTk0NjMuMTIyOTg1NTEucG5nIiwiZXhwIjoxNzgwNDg3MDE3LCJub25jZSI6ImFjOTI3ZGIxMTUyNGUwZWRhYTlmMzc4ZDk4ZWIwOWQ0In0.VU0eXdFjkzGH_RYBvG3PsXcGoypETO7r1qIe7dMExbU