Analisa Teknis Implementasi Flexible Grounding System untuk Sistem Distribusi 20 kV dengan Mempertimbangkan Lokasi dan Kapasitas Distributed Generator

Efendi, Akhmad Rizal (2026) Analisa Teknis Implementasi Flexible Grounding System untuk Sistem Distribusi 20 kV dengan Mempertimbangkan Lokasi dan Kapasitas Distributed Generator. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Sistem distribusi 20 kV pada Gardu Induk (GI) Tanjung, Pulau Lombok, menggunakan sistem pentanahan Neutral Grounding Resistor (NGR) yang membatasi arus gangguan satu fasa ke tanah. Salah satu penyulang yang dilayani, yaitu Penyulang Trawangan, memiliki panjang jaringan 29,92 kms dan sembilan zona proteksi yang menyuplai kawasan wisata Gili Trawangan, Gili Meno, dan Gili Air. Pembatasan arus gangguan oleh NGR menyebabkan grading time antar zona proteksi Ground Fault Relay (GFR) menjadi sangat sempit (0,05–0,155 s), sehingga sering terjadi sympathetic trip ketika terjadi gangguan. Penelitian ini bertujuan memperoleh koordinasi proteksi GFR yang selektif melalui optimasi grading time berbasis algoritma Particle Swarm Optimization (PSO) serta menganalisis penerapan Flexible Grounding System (FGS) yang mengubah nilai NGR dari 500 Ω menjadi 12 Ω secara dinamis saat gangguan terdeteksi. Simulasi gangguan satu fasa ke tanah dilakukan menggunakan perangkat lunak DIgSILENT PowerFactory berbagai variasi impedansi gangguan. Hasil penelitian menunjukkan bahwa PSO mampu menghasilkan grading time sebesar 0,203–0,322 s yang memenuhi grading margin minimum 0,2 s tanpa terjadi perpotongan kurva, dengan konvergensi nilai objective function dari 3,55 menjadi 3,12 pada sekitar iterasi ke-53. Penerapan FGS meningkatkan arus gangguan melalui mekanisme dua tahap (dari 8,05 A menjadi 22,85 A pada gangguan 500 Ω), sehingga mempercepat waktu pemutusan gangguan rata-rata sekitar 30% dan mempersingkat durasi voltage sag dalam dari sekitar 5 s menjadi 0,3 s, sehingga memperbaiki profil tegangan pada titik interkoneksi Distributed Generator (PLTS). Namun demikian, gangguan resistansi tinggi (≥800 Ω) masih belum dapat terdeteksi (No Trip), sehingga masih terdapat blind spot yang menjadi peluang pengembangan selanjutnya.
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The 20 kV distribution sistemat Tanjung Substation in Lombok Islandemploys a Neutral Grounding Resistor (NGR) that limits the single-phase-to-ground fault current. One of its feeders, the Trawangan Feeder, has a network length of 29.92 kms and nine protection zones supplying the tourist areas of Gili Trawangan, Gili Meno, and Gili Air. The fault current limitation imposed by the NGR results in a very narrow grading time between the Ground Fault Relay (GFR) protection zones (0.05–0.155 s), which frequently causes sympathetic trips during faults. This study aims to obtain selective GFR protection coordination through grading time optimization based on the Particle Swarm Optimization (PSO) algorithm and to analyze the implementation of a Flexible Grounding System (FGS) that dynamically changes the NGR value from 500 Ω to 12 Ω when a fault is detected. Single-phase-to-ground fault simulations were carried out using DIgSILENT PowerFactory under various fault impedance values. The results show that PSO produces a grading time of 0.203–0.322 s that satisfies the minimum grading margin of 0.2 s without curve crossing, with the objective function converging from 3.55 to 3.12 at around the 53rd iteration. The FGS increases the fault current through a two-stage mechanism (from 8.05 A to 22.85 A for a 500 Ω fault), accelerating the fault clearing time by an average of about 30% and shortening the deep voltage sag duration from about 5 s to 0.3 s, thereby improving the voltage profile at the Distributed Generator (PV plant) interconnection point. However, high-resistance faults (≥800 Ω) remain undetected (No Trip), indicating a blind spot that constitutes an opportunity for further development.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Flexible Grounding System, Particle Swarm Optimization, Ground Fault Relay, Koordinasi Proteksi, Gangguan Satu Fasa ke Tanah, DIgSILENT PowerFactory. Flexible Grounding System, Particle Swarm Optimization, Ground Fault Relay, Protection Coordination, Single-Phase-to-Ground Fault, DIgSILENT PowerFactory
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK2861 Electric relays. Protective relays--Security measures.
Divisions:	Faculty of Intelligent Electrical and Informatics Technology (ELECTICS) > Electrical Engineering > 20101-(S2) Master Thesis
Depositing User:	Akhmad Rizal Efendi
Date Deposited:	31 Jul 2026 00:30
Last Modified:	31 Jul 2026 00:30
URI:	http://repository.its.ac.id/id/eprint/139618

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