Evaluasi Proyek Overhaul Dengan Menggunakan Metode Cpm, Pert, Smed, Dan Monte Carlo

Basit, Abdul (2026) Evaluasi Proyek Overhaul Dengan Menggunakan Metode Cpm, Pert, Smed, Dan Monte Carlo. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Proyek overhaul pembangkit listrik merupakan kegiatan kritis yang berdampak langsung terhadap keandalan operasi dan nilai Equivalent Availability Factor (EAF) unit pembangkit. Durasi overhaul yang panjang meningkatkan risiko keterlambatan proyek, menurunkan ketersediaan unit, dan menambah biaya kehilangan produksi. Atas dasar tersebut, penelitian ini mengembangkan model evaluasi proyek overhaul dengan mengintegrasikan Critical Path Method (CPM), Program Evaluation and Review Technique (PERT), Single Minute Exchange of Die (SMED), dan simulasi Monte Carlo untuk mengevaluasi percepatan durasi, risiko jadwal, dampak terhadap EAF, dan implikasi biaya.
Studi kasus dilakukan pada proyek major inspection turbin gas GT 2.1, GT 2.2, dan GT 2.3 di PLTGU Grati Blok 2. Jadwal proyek dimodelkan menggunakan Microsoft Project 2019, sementara analisis risiko waktu menggunakan simulasi Monte Carlo (1.000 iterasi, distribusi Beta-PERT) pada ModelRisk. Penerapan SMED secara bertahap mempersingkat durasi overhaul dari 45 hari (eksisting) menjadi 38 hari (Skenario 2, GT 2.3), 35 hari (Skenario 3, GT 2.2), dan 33 hari (Skenario 4, GT 2.1)—penurunan kumulatif 26,7%, tervalidasi penuh oleh realisasi aktual di ketiga unit. Simulasi Monte Carlo menghasilkan P90 berkisar 34,9–48,5 hari, dengan Skenario 4 mencatat risiko keterlambatan terendah (47,3%) dan mean durasi tersingkat (32,9 hari), sementara Skenario 3 memiliki variabilitas durasi terkecil (σ=1,3 hari).
Percepatan durasi berdampak signifikan pada ketersediaan unit: setiap hari pengurangan durasi meningkatkan EAF sebesar ±0,275%, dari 87,5% (eksisting) menjadi 89,4% (Skenario 2), 90,25% (Skenario 3), dan 90,80% (Skenario 4). Analisis manfaat biaya untuk Skenario 3 (kapasitas 100.000 kW, harga jual Rp 975/kWh, percepatan 10 hari) menghasilkan manfaat finansial bersih Rp 19,5 miliar per unit per siklus overhaul, terdiri atas penghematan biaya overhead Rp 846 juta dan nilai produksi listrik yang dipulihkan Rp 18,72 miliar. Temuan ini menegaskan bahwa model evaluasi terpadu yang dikembangkan mampu meningkatkan efisiensi waktu proyek, keandalan unit, dan kinerja ekonomi pembangkit, sehingga dapat dijadikan dasar pengambilan keputusan penjadwalan overhaul berbasis risiko pada pembangkit listrik sejenis. Signifikansi perbedaan durasi antar skenario dikonfirmasi melalui uji non-parametrik Kruskal-Wallis (H = 4.344,81; df = 4; p < 0,0001), dengan uji lanjutan Dunn (koreksi Bonferroni) mengonfirmasi seluruh pasangan skenario berbeda signifikan kecuali Eksisting dibanding Skenario 1.
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Power plant overhaul projects are critical activities that directly impact operational reliability and the unit's Equivalent Availability Factor (EAF). Prolonged overhaul durations increase the risk of project delays, reduce unit availability, and raise production loss costs. Therefore, this study develops an overhaul project evaluation model integrating the Critical Path Method (CPM), Program Evaluation and Review Technique (PERT), Single Minute Exchange of Die (SMED), and Monte Carlo simulation to evaluate duration acceleration, schedule risk, EAF impacts, and cost implications.
A case study was conducted on the major inspection projects of gas turbines GT 2.1, GT 2.2, and GT 2.3 at PLTGU Grati Block 2. The schedule was modeled in Microsoft Project 2019, with time-risk analysis via Monte Carlo simulation (1,000 iterations, Beta-PERT distribution) in ModelRisk. Phased SMED implementation shortened overhaul duration from 45 days (existing) to 38 days (Scenario 2, GT 2.3), 35 days (Scenario 3, GT 2.2), and 33 days (Scenario 4, GT 2.1)—a cumulative 26.7% reduction, fully validated by actual field realization across all three units. Monte Carlo simulation produced P90 values ranging from 34.9 to 48.5 days, with Scenario 4 showing the lowest delay risk (47.3%) and shortest mean duration (32.9 days), while Scenario 3 had the smallest duration variability (σ=1.3 days).
Duration acceleration significantly improved unit availability: each day of reduction raises EAF by ±0.275%, from 87.5% (existing) to 89.4% (Scenario 2), 90.25% (Scenario 3), and 90.80% (Scenario 4). Cost-benefit analysis for Scenario 3 (100,000 kW capacity, IDR 975/kWh selling price, 10-day acceleration) shows a net financial benefit of IDR 19.5 billion per unit per overhaul cycle, comprising IDR 846 million in overhead savings and IDR 18.72 billion in recovered production value. These findings confirm that the integrated model enhances project time efficiency, unit reliability, and economic performance, providing a basis for risk-based overhaul scheduling decisions at similar power plants. The significance of duration differences across scenarios was confirmed using the non-parametric Kruskal-Wallis test (H = 4,344.81; df = 4; p < 0.0001), with Dunn’s post-hoc test (Bonferroni correction) confirming significant differences for all scenario pairs except Existing versus Scenario 1.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	CPM, PERT, SMED, Simulasi Monte Carlo, Uji Kruskal-Wallis, dan EAF.CPM, PERT, SMED, Monte Carlo Simulation, Kruskal-Wallis Test, and EAF.
Subjects:	T Technology > T Technology (General) > T56.8 Project Management
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Industrial Engineering > 26101-(S2) Master Thesis
Depositing User:	Abdul Basit
Date Deposited:	21 Jul 2026 07:25
Last Modified:	21 Jul 2026 07:25
URI:	http://repository.its.ac.id/id/eprint/136005

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