Nurhakimah Mohd Mukhtar
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Nurhakimah Mohd Mukhtar
Official Name
Nurhakimah, Mohd Mukhtar
Alternative Name
Mukhtar, Nurhakimah Mohd
Mokhtar, Nurhakimah Mohd
Mokhtar, N. M.
Mukhtar, Nurhakimah M.
Mukhtar, N. M.
Mohd Mukhtar, Nurhakimah
Mohd Mukhtar, N.
Main Affiliation
Scopus Author ID
55561855200

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Varying the energisation condition to mitigate sympathetic inrush current

2023-12-01 , Nadhirah N.F. , Hana Abdull Halim , Nurhakimah Mohd Mukhtar , Samila Mat Zali

Transformers are generally easy to access and can contribute significantly to entire power system. When a transformer is turned on for the first time, it produces a magnetising inrush current which acts as a starting current. Energisation of transformer has a substantial impact on inrush current and transformer that are connected in parallel. Sympathetic inrush current is a phenomenon that appears when a transformer is switched-on in network whereas the other transformers that was earlier energised. Besides, when sympathetic inrush phenomena occur, the peak and period fluctuate significantly. In this paper, the transformers will be energised in three different ways and each condition will be explored in depth. The operation time of the transformer’s energisation whether it is energised simultaneously or at different times are tested and analysed in terms of their characteristics. It is performed using power system computer aided design (PSCAD) software, starting with a develop model of the energisation and then generate the outcomes. The results of the simulation demonstrate that energising the transformer in different ways can give different effect on the sympathetic inrush current, as well as the variables that affect it and methods for reducing it

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Explicit Solution of Parameter Estimate using Multiparametric Programming for Boost Converter

2023 , Ernie Che Mid , Nurhakimah Mohd Mukhtar , Syarifah Hanisah Syed Yunus , Dayanasari Abdul Hadi , Eliyana Ruslan

This work proposes an approach to estimate the parameters of capacitance and inductance in a boost converter using an explicit solution. A multiparametric programming (MPP) algorithm is fundamental to the suggested methodology, which aims to develop parameters as explicit functions of measurements. In this method, the generalised mathematical model of the boost converter is discretised into an algebraic equation. The parameter estimation problem is then formulated and solved using Karush-Kuhn-Tucker. Finally, an explicit solution of estimate parameters such as capacitor and inductor is formulated as an explicit function of the inductor currents and capacitor voltage. Finally, the state variables of the boost converter are numerically obtained and used to test the capability of the proposed work. The results presented in this work prove the MPP algorithm can estimate the boost converter's parameters, which can be extended to other power converters and filters.

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A Comprehensive Study on Magnetic Materials Selection for Power Electronic Converters

2023-01-01 , Rahman M.Z. , Nurhakimah Mohd Mukhtar

The size and efficiency of converters are key considerations to ensure optimal power management across electrical networks, which significantly affect industrial, aeronautical, and automobile use. Frequently, the converter's most important component is the inductor. The appropriate inductor can eliminate the current ripple at the converter's input. Therefore, choosing the right component is crucial for a converter design. The operating frequency range of power converters is selected from 20 kHz to 150 kHz. Whenever the switching frequency is raised from 20 to 150 kHz, the converter volume shrinks by 59.5% and weight is lowered by 58.4%. This study compares the magnetic materials utilized in a realistic design. Iron-based amorphous metals, nanocrystalline, alloy-powdered, silicon steel and ferrite materials are among the substances under this research. The type of converters, magnetic materials, features and their shape selection are discussed. Finally, based on some prior research, we proposed that powdered material cores are the best choice for power electronic converters.

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Lightning Strikes Mitigation Plan on Transmission Line Tower at Kedah Paddy Field

2021-06-11 , Othman N.A. , Halim H.A. , Wooi Chin Leong , Melaty Amirruddin , Nurhakimah Mohd Mukhtar

This paper presents a mitigation plan for lightning strikes towards the transmission line tower at Kedah paddy field area. The ATP Draw software produces a schematic diagram of an incoming main intake sub-station and a transmission tower struck by lightning. Simulation on multiple soil resistance values and multiple soil conditions are then plot into graphs. A static eliminator reduces the electrostatic force between negatively charged thunder clouds with a positively charged steel transmission tower. It shows that a static eliminator makes the transmission line act invisibly in the lightning pathway. This protection level avoids surge current from transmitting in the transmission line reduces the possibility to damage surge arrestor.

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Characterization of Photovoltaic Module Under Random Partial Shading Conditions

2022-01-01 , Rahman N.A. , Mohammad Faridun Naim Tajuddin , Nurhakimah Mohd Mukhtar , Muhammad Zaid Aihsan

Photovoltaic (PV) systems have been gaining the pace in energy market for the past decade. Reducing capital costs and government incentives are among other factors that drive the PV forward. PV massively depends on the sunlight that falls onto its surface to generate electricity. However, partial shading events are a common nemesis to the PV systems. It happened when some part of the PV panel's surface did not receive the maximum light energy. It can be caused by passing clouds, nearby trees or poles, leaves, bird dropping, etc. The harvested power drops during this event, hence the overall system's efficiency is also affected. This paper investigates the characteristic of the single panel system during various partial shading conditions. The identification of the maximum power point (MPP) location and the intensity of the event to occur at the region on the P-V plane is given priority in this study. All in all, this study aims to provide useful information for considerations in the process of designing the converters.

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Computational study of the structural, mechanical, electronic, optical and thermal properties of BaLiX (X =P, As, Sb) perovskites

2024-11 , Md Zillur Rahman , Sayed Sahriar Hasan , Mist Shamima Akter , Nurhakimah Mohd Mukhtar , Nazifa Absar , Md Akib Hasan , Tom Ichibha , Ryo Maezono , Kenta Hongo , Md Ariful Islam

This study explores the structural, optical, mechanical, electronic, and thermal characteristics of ionic semiconductor compounds BaLiX (X = P, As, Sb) using Density Functional Theory (DFT). A comprehensive analysis of BaLiX (X = P, As, Sb) is conducted, proving that the estimated and observed lattice parameters coincide well and confirming mechanical stability through elastic stiffness constants. Electronic band structures reveal direct bandgap semiconductor properties with values of 0.70 eV, 0.30 eV, and 0.95 eV for BaLiP, BaLiAs, and BaLiSb, respectively, suggesting specific applications such as mid-infrared photodetectors, terahertz devices, and near-infrared sensors. Optical property analyses, including energy loss function, reflectivity, refractive index, and absorption coefficient, highlight the potential of these materials for optoelectronic and photovoltaic applications. Despite elastic anisotropy, optical anisotropy remains minimal. The materials exhibit potential for use as thermal barrier coatings (TBC) due to their comparatively lower Debye temperature (D), minimum thermal conductivity (Kmin) and lattice thermal conductivity (kph). Moreover, heat capacity calculations and thermal coefficient of expansion are also calculated.

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