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All Journal TEKNIK Kitektro CIRCUIT: Jurnal Ilmiah Pendidikan Teknik Elektro AJAD : Jurnal Pengabdian kepada Masyarakat kawanad jes PESARE: Science and Engineering Service Journal Jurnal Polimesin
Lubis, Rakhmad Syafutra
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Aerospace Engineering Humanities Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Education Electrical & Electronics Engineering Engineering Environmental Science Materials Science & Nanotechnology Mechanical Engineering Public Health Other

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Transformer Oil Failure Analysis Based on Dissolved Gas Analysis (DGA) Test Using Breakdown Voltage and Fuzzy Logic Methods Lubis, Rakhmad Syafutra; Akbar, Muhammad Hafizh; Siregar, Ramdhan Halid; Masri, Masri
Journal of Engineering and Science Vol. 4 No. 2 (2025): December
Publisher : Yayasan Kawanad

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.56347/jes.v4i2.381

Abstract

A common problem that occurs in transformers is failure of the insulating oil. One solution to prevent this disruption is to analyze indications of insulating oil failure. Several previous studies on the analysis of transformer insulating oil failure were based on dissolved gas content tests of transformer oil samples. The research was conducted using several methods in processing dissolved gas test results data, such as the TDCG (Total Dissolved Combustible Gas), Roger's Ratio, and Duval's Triangle methods. In this study, two methods were used for comparison, namely the Breakdown Voltage method and the Fuzzy Logic method. The results obtained show that the condition of the insulating oil using fuzzy logic in the Matlab simulation is in accordance with the condition of the transformer insulating oil based on its breakdown voltage characteristics, namely in a normal state. Meanwhile, gas content that is at a high or very high level has a significant impact on the indication of failure in transformer insulating oil, namely the concentration of TDCG and nitrogen gas content.
Design and implementation of a state feedback controller for enhanced speed stability of permanent magnet DC motors under load variations Syukri, Mahdi; Lubis, Rakhmad Syafutra; Melinda, Melinda; Syukur, Muhammad Hakkan; Hasanuddin, Iskandar; Irwanto, Muhammad
Jurnal Polimesin Vol 24, No 2 (2026): April
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i2.8379

Abstract

This study presents the design and simulation of a State Feedback Controller (SFC) for speed regulation of a Permanent-Magnet DC (PMDC) motor using a state-space modeling approach. The objective is to achieve stable and accurate speed control under dynamic load disturbances that typically degrade the performance of conventional open-loop systems. The Direct Current (DC) motor is modeled in state-space form, with armature current and angular speed selected as the main system states. Controller gains are designed using the pole placement method to ensure fast response and improved stability. The proposed SFC is evaluated through MATLAB®/Simulink® simulations by examining motor speed, armature current, and input voltage responses under step-load variations. Simulation results show that the SFC maintains the motor speed at the reference value of 3,430 rpm even during sudden load increases, whereas the uncontrolled motor experiences significant speed drops and oscillations. Performance analysis confirms notable improvements in transient response. The rise time is reduced from 1.1864 s to 0.4220 s, and the settling time decreases from 2.1132 s to 0.7517 s, indicating faster and more stable system behavior. In addition, smoother current transitions and more efficient voltage regulation are achieved compared to the open-loop configuration. Overall, the results demonstrate that state-space control using pole placement provides a robust and responsive alternative to conventional PID controllers for DC motor speed control under load disturbances. Future work will focus on experimental validation and the exploration of advanced control strategies such as Linear Quadratic Regulation and adaptive control.
Co-Authors Abdul Haris Akbar, Muhammad Hafizh Andri Andri Hasanuddin, Iskandar Hubbul Walidainy Ira Devi Sara Irwanto, Muhammad Mahdi Mahdi, Mahdi Mahdi Syukri Masri Masri Masri Melinda Melinda Muhayatsyah, Teuku Panggabean, Ulil Azmi Putra, T. Edisah Ramdhan Halid Siregar Saifuddin Muhammad Jalil Suriadi Suriadi Syukur, Muhammad Hakkan Tarmizi Tarmizi Yuwaldi Away