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All Journal TELKOMNIKA (Telecommunication Computing Electronics and Control) Bulletin of Electrical Engineering and Informatics Indonesian Journal of Electrical Engineering and Computer Science
Mohd Shahril Ahmad Khiar
Universiti Teknikal Malaysia Melaka
Computer Science & IT Electrical & Electronics Engineering

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Investigation of Wave Propagation to PV-Solar Panel Due to Lightning Induced Overvoltage Nur Hidayu Abdul Rahim; Zikri Abadi Baharudin; Md Nazri Othman; Zahriladha Zakaria; Mohd Shahril Ahmad Khiar; Nur Zawani Saharuddin; Azlinda Ahmad
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 12, No 1: March 2014
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v12i1.22

Abstract

Lightning produces extremely high voltages that generated induce overvoltage which have a high tendency to effect the electrical apparatus especially renewable energy plant that directly expose to this source. This study was performed through experimental work by investigating the effect of induce overvoltage upon the photovoltaic system. The induce voltage was performed by using lightning impulse generator. It is found that the maximum voltage of the unwanted signal is proportional with the distant of the specimen. The closer distant between solar panel material and spark discharge, the more serious effect would occur due to the induced overvoltage. 
Effect of repeated electrical breakdowns on mineral and natural ester insulating oils Sharin Ab Ghani; Mohd Shahril Ahmad Khiar; Imran Sutan Chairul; Muhammad Imran Zamir
Bulletin of Electrical Engineering and Informatics Vol 10, No 6: December 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v10i6.3258

Abstract

Transformer insulating oils are exposed to repeated electrical discharge or breakdowns inside power transformers. Durability tests are conducted to analyze the ability of oil to resist decomposition due to such high electrical stresses. With the increasing demand for alternative insulating oils for oil-immersed transformers, it is worthy to compare the performance of different types of insulating oils (conventional mineral-based insulating oil and natural ester-based insulating oil) under repeated electrical breakdown. In this paper, the AC breakdown voltage of different mineral-based and natural ester-based insulating oils is reported. Durability tests were conducted based on the AC breakdown voltage behavior of insulating oils after 50 electrical breakdown shots. The AC breakdown voltage of each insulating oil sample was assessed according to the ASTM D1816 standard test method. Based on the results, it can be concluded that the dissimilarity in chemical composition of the insulating oils has a significant effect on the AC breakdown voltage behavior of these oils under repeated electrical breakdowns.
Effect of electrical discharge on the properties of natural esters insulating fluids Imran Sutan Chairul; Sharin Ab Ghani; Nur Hakimah Ab Aziz; Mohd Shahril Ahmad Khiar; Muhammad Syahrani Johal; Mohd Aizzat Azmi
Indonesian Journal of Electrical Engineering and Computer Science Vol 23, No 3: September 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v23.i3.pp1281-1288

Abstract

Vegetable oils have been an alternative to mineral oil for oil-immersed transformers due to concern on less flammable, environmental-friendly, biodegradable, and sustainable resources of petroleum-based insulating oil. This paper presents the effect of electrical discharges (200 up to 1000 discharges) under 50 Hz inhomogeneous electric field on the properties (acidity, water content, and breakdown voltage) of two varieties of vegetable based insulating oils; i) natural ester (NE) and ii) low viscosity insulating fluids derived from a natural ester (NELV). Results show the water content, acidity and breakdown voltage of NE fluctuate due to applied discharges, while NELV display insignificant changes. Hence, results indicate that the low viscosity insulating fluids derived from natural ester tend to maintain their properties compared to natural ester.
Effect of mixing ratio on the breakdown voltage of mineral and natural ester insulating oil blends Sharin Ab Ghani; Imran Sutan Chairul; Mohd Shahril Ahmad Khiar; Nor Hidayah Rahim; Syahrun Nizam Md Arshad@Hashim
Bulletin of Electrical Engineering and Informatics Vol 11, No 5: October 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v11i5.3723

Abstract

To date, the most common insulating oil used in oil-immersed transformers is mineral insulating (MI) oil, which is derived from petroleum. Owing to the depletion of petroleum over the years, it can be anticipated that petroleum-derived products such as MI oils will also deplete in the future. MI oils are not only non-renewable, but they are also non-biodegradable, where these oils are harmful to the environment in cases of oil spillage. Therefore, the aim of this study is to investigate the potential of mixing MI oil with natural ester insulating (NEI) oil in order to reduce the high dependency on MI oil for transformer applications. The MI and NEI oils were mixed with different mixing ratios. AC breakdown voltage test was conducted on the MI-NEI oil blends according to the ASTM D1816 standard. From the results, it is found that the following mixing ratios (30% of MI oil + 70% of NEI oil, 20% of MI oil + 80% of NEI oil) result in significant improvement in terms of the AC breakdown voltage compared with unused MI oil. The flash point and corrosivity levels of the oil blends were also examined.
Color enhancement of refined-bleached used vegetable oils as dielectric liquid: two-level factorial design approach Muhammad Syahrani Johal; Sharin Ab Ghani; Imran Sutan Chairul; Mohd Shahril Ahmad Khiar; Muhamad Falihan Bahari
Bulletin of Electrical Engineering and Informatics Vol 12, No 3: June 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v12i3.4988

Abstract

Number of findings have shown that the used vegetable oils (UVOs) properties can be enhanced by changing their chemical structure and can be utilized as dielectric liquid in oil-immersed transformers. However, earlier researchers used the one-factor-at-a-time (OFAT) method for their experimental design approach. Nevertheless, they failed to consider the possibility that combining the mixing process parameters at the highest ratios could produce a more favorable outcome. Hence, in this study, two-level (2k) factorial design is applied to achieve the highest color reduction of UVOs through chemical refining process known as refined-bleached UVOs (RBUVOs). The involved process parameters are oil temperature, mixing speed and mixing time. Based on the results of 23 factorial design, it is found that mixing time and oil temperature has the most significant effects on color reduction, with a percentage contribution of 35.00% and 32.51%, respectively. The result also shows that the best mixing process parameters of RBUVOs were oil temperature (80 °C), mixing speed (1,000 rpm) and mixing time (60 min). These resulted in the highest color reduction of RBUVOs by 79.27%.
Acidity improvement of refined-bleached used vegetable oils as dielectric liquid using two-level factorial design Muhammad Syahrani Johal; Sharin Ab Ghani; Imran Sutan Chairul; Mohd Shahril Ahmad Khiar; Mohamad Nazri Mohamad Din
Bulletin of Electrical Engineering and Informatics Vol 12, No 3: June 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v12i3.4922

Abstract

Recent studies have shown that modifying the chemical structure of used vegetable oils (UVOs) as an alternative dielectric liquid for oil-immersed transformers has improved these oils' physical, electrical and chemical properties. However, previous researchers have implemented the one-factor-at-a-time method as their experimental design approach. Therefore, they overlooked the possibility that combining mixing process parameters at optimum ratios will yield a better result. Hence, in this study, the two-level (2k) factorial design is applied to achieve the lowest acidity level of UVOs through chemical refining process namely as refined-bleached used vegetable oils (RBUVOs). The involved process parameters are oil temperature, mixing speed and mixing time. Based on the results of 23 factorial design, it is found that oil temperature has the most significant effect on acidity, with a percentage contribution of 35.76%. The result also shows that the best mixing process parameters of RBUVOs were: oil temperature (60 °C), mixing speed (1,000 rpm) and mixing time (30 min). Note that these mixing process parameters produced better RBUVOs with an acidity value of 0.0221 mg KOH/g. A regression model is also developed to predict the acidity of RBUVOs as a function of oil temperature, mixing speed and mixing time.
Effects of parameter adjustment on the electromagnetic field of an overhead power transmission line model Sharin Ab Ghani; Mohd Shahril Ahmad Khiar; Imran Sutan Chairul; Nor Hidayah Rahim; Syahrun Nizam Md Arshad@ Hashim
Indonesian Journal of Electrical Engineering and Computer Science Vol 30, No 2: May 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v30.i2.pp643-650

Abstract

Studies have shown that high-voltage power transmission lines emit electromagnetic radiation, which has adverse effects on human health. This paper presents the effects of parameter adjustment on the electric and magnetic fields of an overhead power transmission line model at human height. A finite element software, COMSOL multiphysics, was used to simulate the electric and magnetic fields. The electric and magnetic fields generated by the 1200-kV and 220-kV overhead power transmission line models were first computed and the models were validated by comparing the simulation results with those of previous studies. Numbers of parameter were adjusted in order to investigate their effects on the electric and magnetic field distributions. Based on the results, the electric field intensity increases with an increase in the voltage of the conductors. The magnetic field density increases with an increase in the current carried by the conductors. A voltage of 700 kV results in an electricity field intensity that exceeds the residential safety limit (50 kV/m) set by the International Commission on Non-Ionizing Radiation Protection. Hence, a proper right-of-way is needed to ensure that residential areas are at a safe distance away from transmission towers.
Co-Authors Azlinda Ahmad Imran Sutan Chairul Imran Sutan Chairul Md Nazri Othman Mohamad Nazri Mohamad Din Mohd Aizzat Azmi Muhamad Falihan Bahari Muhammad Imran Zamir Muhammad Syahrani Johal Nor Hidayah Rahim Nur Hakimah Ab Aziz Nur Hidayu Abdul Rahim Nur Zawani Saharuddin Sharin Ab Ghani Sharin Ab Ghani Syahrun Nizam Md Arshad@ Hashim Syahrun Nizam Md Arshad@Hashim Zahriladha Zakaria Zikri Abadi Baharudin