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Journal : International Journal of Electrical and Computer Engineering

Analysis of interference methods on transformers based on the results of dissolved gas analysis tests Yulianta Siregar; Timothy Juan Hartanto Lumbanraja
International Journal of Electrical and Computer Engineering (IJECE) Vol 13, No 4: August 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v13i4.pp3672-3685

Abstract

In the operation of the power transformer, several maintenance efforts must be made to ensure the condition of the transformer is in good condition. The problems that usually arise are a thermal failure and electrical failure. The use of insulating media such as transformer oil and transformer insulation paper can be disrupted by this failure. Dissolved gas analysis, which identifies the types and concentrations of dissolved gas in transformer oil, can reveal details on fault indicators in power transformers (DGA). In this study, we used the interpretation of the IEEE std 2008-C57.104 (total dissolved combustible gas (TDCG), key gas, Rogers ratio method), the interpretation of IEC 2015-60599 (Duval triangle and basic gas ratio method), and the IEEE Std 2019-C57.104 interpretation (Duval pentagon method). The outcome of the DGA test is used to determine the conditions and indications of disturbances in the transformer for power. Using various gas analysis techniques also impacts the outcome of the fault indication. This variation has affected the types of gas used in the computation and the gas concentration limit value estimation. After the gas analysis, it was found that the oil purification process was also proven to reduce the concentration of combustible gases.
Numerical analysis in Ar-H2 coupled-coil inductively coupled thermal plasma with Si feedstock for stable operation Yulianta Siregar; Yasunori Tanaka
International Journal of Electrical and Computer Engineering (IJECE) Vol 13, No 4: August 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v13i4.pp3695-3705

Abstract

In nanopowder synthesis, the starting powder to be evaporated is infused in a plasma torch through the upper coil and the lower coil in the coupled model of inductively coupled thermal plasma (coupled-coil inductively coupled thermal plasma (ICTP)). Mixing these evaporated materials to form the coupled ICTP significantly influences the thermodynamic and transport properties. It is essential to understand these complex interactions between coupled ICTP and feedstock evaporation. This research investigated the thermal interactions between silicon raw material powder (Si) with ICTP in coupled 99%Ar/1%H2 through the numerical model developed for the synthesis of Si nanopowder. The feed rate of the Si raw material was set at 0.05, 0.1, and 0.5 g/min. This implies that the increased Si feed is too heavy to vaporize all the injected feed.
Comparative design of harmonic current reduction in variable speed drive using space vector pulse width modulation and hybrid pulse width modulation Siregar, Yulianta; Situmeang, Farel; Mohamed, Nur Nabila
International Journal of Electrical and Computer Engineering (IJECE) Vol 14, No 5: October 2024
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v14i5.pp4907-4920

Abstract

In industry and commerce, three-phase induction motors are frequently utilized as the primary power source for machinery. However, to increase motor performance efficiency, induction motors also need a tool for speed control. The variable speed drive (VSD) is one tool used to control the rotation speed of three-phase induction motors. Since VSD is a non-linear load, harmonic distortion will result from it. The space vector pulse width modulation (SVPWM) injection method and the hybrid pulse width modulation method were the two techniques employed by the author in this study to lower the current in the VSD. With the SVPWM injection approach, the variable speed drive's current total harmonic distortion (THD) values in the R, S, and T phases dropped to 3.77%, 3.53%, and 2.19% from 7.14%, 7.17%, and 7.58%.
Dynamic voltage restorer quality improvement analysis using particle swarm optimization and artificial neural networks for voltage sag mitigation Siregar, Yulianta; Muhammad, Maulaya; Arief, Yanuar Zulardiansyah; Mubarakah, Naemah; Soeharwinto, Soeharwinto; Dinzi, Riswan
International Journal of Electrical and Computer Engineering (IJECE) Vol 13, No 6: December 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v13i6.pp6079-6091

Abstract

Power quality is one of the problems in power systems, caused by increased nonlinear loads and short circuit faults. Short circuits often occur in power systems and generally cause voltage sags that can damage sensitive loads. Dynamic voltage restorer (DVR) is an efficient and flexible solution for overcoming voltage sag problems. The control system on the DVR plays an important role in improving the quality of voltage injection applied to the network. DVR control systems based on particle swarm optimization (PSO) and artificial neural networks (ANN) were proposed in this study to assess better controllers applied to DVRs. In this study, a simulation of voltage sag due to a 3-phase short-circuit fault was carried out based on a load of 70% of the total load and a fault location point of 75% of the feeder’s length. The simulation was carried out on the SB 02 Sibolga feeder. Modeling and simulation results are carried out with MATLAB-Simulink. The simulation results show that DVR-PSO and DVR-ANN successfully recover voltage sag by supplying voltage at each phase. Based on the results of the analysis shows that DVR-ANN outperforms DVR-PSO in quality and voltage injection into the network.
Dynamic voltage restorer performance analysis using fuzzy logic controller and battery energy storage system for voltage sagging Siregar, Yulianta; Azhari Nasution, Azrial Aziz; Suan Tial, Mai Kai; Mubarakah, Naemah; Soeharwinto, Soeharwinto
International Journal of Electrical and Computer Engineering (IJECE) Vol 14, No 2: April 2024
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v14i2.pp1215-1227

Abstract

Power quality is a major issue in the power transfer process. This is caused by disturbances such as voltage sags, voltage spikes, and harmonics. Voltage sag is the most common disturbance in the electric power system. However, the dynamic voltage restorer (DVR) is the most effective device for voltage sags. This research uses the DVR to overcome voltage sags using fuzzy logic controller (FLC) and battery energy storage system (BESS) to improve the performance of the DVR. The results showed that DVR using FLC improved the quality of voltage recovery compared to BESS because FLC injected a greater voltage of 0.0991 pu than BESS.
Comparison design of dynamic voltage restorers, distribution static compensators and unified power quality conditioner series shunts on voltage sag, and voltage swell Siregar, Yulianta; Mubarok, Syahrun; Mohamed, Nur Nabila
International Journal of Electrical and Computer Engineering (IJECE) Vol 15, No 2: April 2025
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v15i2.pp1396-1410

Abstract

One issue with the power system is electrical power quality, which is brought on by short circuit disruptions and growing nonlinear loads. Power systems frequently have short circuits, resulting in voltage sags that can harm delicate loads. Voltage sage and swell issues can be resolved using unified power quality conditioner series shunts (UPQC-S), distribution static compensators (DSTATCOM), and dynamic voltage restorers (DVR). Custom power devices are very useful in overcoming problems with electrical networks. In this research, due to 3-phase short circuit faults, voltage sag and swell simulations were conducted using a load equal to 70% of the total load and a fault location point of 75% of the feeder length, from the results of research conducted with the case study PT. PLN (Persero) UP3 Sibolga Feeder SB 02 shows that DVR performs better than DSTATCOM and UPQC-S in handling voltage sag and voltage swell due to 3-phase short circuit disturbances. The DVR succeeded in providing the largest voltage sag recovery in phase C, increasing the voltage from 0.2481 pu to 0.9776 pu. The DVR is also effective in overcoming voltage swell on phase A, reducing it from 1.724 pu to 0.9969 pu.
Comparative analysis of active filters, inductor-capacitor and inductor-capacitor-inductor passive filters in reducing harmonics Siregar, Yulianta; Azhari, Naomi; Mohamed, Nur Nabila
International Journal of Electrical and Computer Engineering (IJECE) Vol 15, No 3: June 2025
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v15i3.pp2567-2582

Abstract

Control equipment at substations requires a rectifier to convert alternative current (AC)-direct current (DC) electric current to provide DC power for relays, motors for disconnector switches and power breaker switches, and telecommunications equipment. Rectifiers have non-linear load characteristics, which can result in a waveform that is not pure sinusoidal due to the interaction of fundamental frequency sinusoidal waves with other waves known as harmonics. Therefore, to not interfere with the equipment's work, a filter is needed to reduce the harmonics produced by the rectifier. In this research, using MATLAB/Simulink, prevention was carried out using active filters, inductor-capacitor (LC), and inductor-capacitor-inductor (LCL) passive filters (Ta, Tc, and Td designs) separately. After the research was carried out, it was found that the amount of harmonics before installing the filter was 49.61%. Then, after installing the active filter, the harmonics were reduced to 0.29%, the installation of the passive LC filter was reduced to 9.29%, and the installation of the LCL filter (Ta, Tc, and Td) became 1.44%, 0.29%, and 1.44%.