Resilient Operation of IBR-Dominated Feeders Using AdaptiveRelays with Optimal Arrester Placement: Case Study of Cross RiverState 132kV Network
Keywords:
Inverter-Based Resources, Adaptive Protection, Surge Arrester Placement, Resilience, TW87, LIPL, TOV, Optimal Power Flow, Cross River State, ETAP.Abstract
This study presents a coordinated adaptive relaying and optimal surge arrester placement framework to enhance the resilience of inverter-based resource (IBR) dominated 132/33/11kV feeders, validated on the Cross River State Calabar–Obudu network. Base case AC optimal power flow analysis of the 36.8 MW system revealed severe voltage violations with Ogoja and Obudu buses at 0.923 pu and 0.912 pu, respectively, total losses of 4.91 MW (13.3%), and a SAIDI of 9.2 hrs/yr due to lightning outages. Integration of 15 MW solar at Ogoja and 10 MW diesel at Obudu without coordination further degraded protection performance, as IBRs limit fault current to 1.2 pu, causing conventional 51V and 21M relays to under-reach and misoperate.
A genetic algorithm optimization for surge arrester placement to determined four optimal locations versus six per IEEE C62.22.1, reducing CAPEX by 33% from $48,000 to $32,000 while improving performance. The proposed GA scheme lowered losses to 2.28 MW, raised minimum voltage to 0.958 pu, limited peak overvoltage to 100 kVp, and improved SAIDI to 1.7 hrs/yr and EENS to 185 MWh/yr. To address IBR-induced protection challenges, a Proximal Policy Optimization deep reinforcement learning algorithm trained for 10,000 episodes derived three adaptive setting groups. As IBR penetration increased from 0–50%, relay impedance settings adapted from 18.2 Ω to 28.1 Ω and 51V pickup from 450 A to 120 A, maintaining coordination margins where Z-set < LIPL/Ifmin under all scenarios. TW87 traveling-wave protection enabled 3.8 ms fault clearing versus 65 ms base case.
The integrated framework reduced total losses by 51.5%, improved minimum voltage by 5.0%, decreased SAIDI by 81.5% and EENS by 84.6%, and increased the Resilience Index from 0.42 to 0.846, a 101% improvement. Results confirm that coordinated arrester placement with PPO-DRL adaptive relaying ensures NERC voltage compliance, clamps lightning transients below 121 kVp, and achieves 94.2% faster tripping, providing a cost-effective solution for resilient operation of IBR-dominated transmission networks under lightning and high renewable penetration.
References
IEEE Std C62.11-2020, “IEEE Standard for Metal-Oxide Surge Arresters for AC Power Circuits (>1 kV)”, 2020.
IEEE Std 2800-2022, “IEEE Standard for Interconnection and Interoperability of Inverter-Based Resources Interconnecting with Associated Transmission Electric Power Systems”, 2022.
NERC, “Nigerian Grid Code Version 03: Connection Conditions for Generators”, 2018.
J. L. Blackburn and T. J. Domin, Protective Relaying: Principles and Applications, 4th ed. CRC Press, 2014.
A. K. Ezea et al., “Impact of Solar PV on Protection of Distribution Networks in Nigeria,” Nigerian Journal of Technology, vol. 39, no. 2, pp. 456–463, 2020.
Schweitzer Engineering Laboratories, “Traveling-Wave Fault Location and Protection for IBR Grids,” SEL Technical Report, 2021.
ABB, “TOV-Hardened Surge Arresters for Solar Applications,” Application Note 1HC0075842, 2022.
Y. Zhang et al., “Deep Reinforcement Learning for Adaptive Protection in Active Distribution Networks,” IEEE Trans. Smart Grid, vol. 14, no. 1, pp. 234–245, Jan. 2023.
IEEE Std 1366-2012, “IEEE Guide for Electric Power Distribution Reliability Indices”, 2012.
ETAP, “Lightning and Switching Transient Analysis,” ETAP 23.0 User Guide, 2023.
TCN, “Annual Technical Report: System Collapse and SAIDI Data,” Transmission Company of Nigeria, Abuja, 2023.
IEC 60099-4, “Metal-oxide surge arresters without gaps for a.c. systems”, 2014.
P. M. Anderson, Power System Protection, IEEE Press, 1999.
M. H. J. Bollen and F. Hassan, Integration of Distributed Generation in the Power System, Wiley-IEEE Press, 2011.
N. Schweitzer, E. O., Kasztenny, B., & Mynam, V. (2021). Traveling-Wave Fault Location and Protection for IBR Grids. Schweitzer Engineering Laboratories.
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