Koordinasi Proteksi Add On Combined Cycle Project Plant PLTGU Muara Tawar Berbasis Adaptive Modified Firefly Algorithm

Muhammad Fakhri Hadiyanto, Prof. Dr.Eng. Ir. F. Danang Wijaya, S.T., M.T., IPM. ; Dr. Ir. M. Isnaeni Bambang Setyonegoro, M.T.

2026 | Tesis | S2 Teknik Elektro

Transformasi Pembangkit Listrik Muara Tawar menjadi Pembangkit Listrik Tenaga Gas Uap (PLTGU) dengan penambahan kapasitas sebesar 650 MW menuntut sistem proteksi yang cepat, selektif, dan andal, khususnya pada tahap commissioning dan masa warranty defect notice periode 2024–2026. Insiden hubung singkat dengan arus sebesar 23,7 kA yang menyebabkan kerusakan pada Unit Auxiliary Transformer (UAT) saat penutupan bus tie menunjukkan bahwa sistem proteksi eksisting yang mengandalkan Low Stage Overcurrent Relay dengan waktu tunda 0,6–0,885 detik belum optimal dalam merespons gangguan. Penelitian ini menerapkan Adaptive Modified Firefly Algorithm (AMFA) untuk mengoptimalkan koordinasi rele arus lebih berkarakteristik waktu invers dengan fokus pada penentuan nilai Time Dial Setting (TDS) guna meminimalkan waktu operasi rele utama tanpa mengabaikan kriteria selektivitas dengan menjaga nilai Coordination Time Interval (CTI) 0,2 detik sesuai standar IEEE 242. Selain itu, penentuan setting juga mempertimbangkan kondisi non-gangguan seperti arus starting motor dan arus inrush transformator guna mencegah terjadinya false trip. Proses optimasi dilakukan menggunakan MATLAB dan diverifikasi melalui simulasi ETAP pada beberapa skenario tipikal sistem. Hasil penelitian menunjukkan bahwa metode AMFA mampu menghasilkan koordinasi proteksi yang lebih optimal dibandingkan metode manual, dengan waktu operasi yang lebih cepat serta kesesuaian hasil yang tinggi terhadap simulasi ETAP, di mana seluruh skenario pengujian memenuhi kriteria CTI dan menunjukkan peningkatan kinerja sistem proteksi dalam mengisolasi gangguan secara cepat dan selektif tanpa terganggu kondisi non-fault, sehingga metode yang diusulkan terbukti efektif dalam meningkatkan keandalan sistem proteksi serta meminimalkan risiko kerusakan peralatan pada sistem PLTGU Muara Tawar.

The transformation of Muara Tawar Power Plant into a Combined Cycle Power Plant (PLTGU) with an additional capacity of 650 MW necessitates a fast, selective, and reliable protection system, particularly during the commissioning stage and the warranty defect notice period of 2024–2026. A short-circuit incident with a fault current of approximately 23.7 kA, which caused damage to the Unit Auxiliary Transformer (UAT) during bus tie closing, indicates that the existing protection system relying on a Low Stage Overcurrent Relay with a delay time of 0.6–0.885 seconds is not optimal in responding to faults. This study applies the Adaptive Modified Firefly Algorithm (AMFA) to optimize the coordination of inverse time overcurrent relays, focusing on determining the optimal Time Dial Setting (TDS) to minimize the operating time of the primary relay while maintaining selectivity by ensuring a Coordination Time Interval (CTI) of 0.2 seconds in accordance with IEEE 242 standards. In addition, the relay setting considers non-fault conditions such as motor starting currents and transformer inrush currents to prevent false tripping. The optimization process is conducted using MATLAB and verified through ETAP simulations under several typical system scenarios. The results show that the AMFA method is capable of producing more optimal protection coordination compared to manual methods, with faster operating times and a high level of agreement with ETAP simulation results. All tested scenarios satisfy the CTI criteria and demonstrate improved protection system performance in isolating faults quickly and selectively without being affected by non-fault conditions. Therefore, the proposed method is proven to be effective in enhancing the reliability of the protection system and minimizing the risk of equipment damage in the Muara Tawar PLTGU system.

Kata Kunci : Koordinasi proteksi, time dial setting, rele arus lebih, firefly algorithm