Ahmad Zaidi Abdullah
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Preferred name
Ahmad Zaidi Abdullah
Official Name
Ahmad Zaidi, Abdullah
Alternative Name
Bin Abdullah, Ahmad Zaidi Bin
Abdullah, Ahmad Zaidi Bin
Abdullah, Ahmad Zaidi
Abdullah, A. Z.
Main Affiliation
Scopus Author ID
56878313200
Researcher ID
W-3280-2019

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  • Publication
    The impact of tourism performance on sports industry in Thailand and Indonesia
    ( 2021-07-21)
    Mohammad Harith Amlus
    ;
    Rashid I.M.A.
    ;
    Samah I.H.A.
    ;
    Nazmizan Muhammad
    ;
    Ahmad Faizal Salleh
    ;
    Ahmad Zaidi Abdullah
    The COVID-19 epidemic has thrown Indonesia's sports calendar into confusion, with many high-profile sporting events rescheduled or postponed for the foreseeable future. Tourism is one of the greatest vital sectors pouring the Thai economy, which can constantly generate great income for Thailand and Indonesia. The number of international tourist arrivals to Thailand in 2018 reached 38.12 million people and Indonesia sport tourism received 250,000 foreign tourists in 2018. Based on an all-encompassing approach, this research has exposed that integrating various strategies for tourism expansion with sound government policies and proactive management practices have led to significant positive outcomes towards mutual success of tourism sectors of Thailand. Additionally, the paper delivers considered policy to drive long-lasting enhancements in tourism sector, exchange rate and service sectors through efficient management and intelligent utilization of resources in tourism sector. The recent shocks in provide and demand within the world aren't because of sudden economic reasons. Indeed, associated with Covid-19 that causes speedily spreading world health issues and life threats round the world coping with the social issues created by Covid-19 pandemic, they ought to not neglect the economic changes created by this pandemic. The government-ordered lockdowns have discontinuous life for billions and within the same time creates economic collapse situation. The foremost vital of those economic changes in developing countries with high fragility is exchange rates caused by sports and tourism industry, as a result of exchange rates will directly have an effect on several economics variables, from inflation to foreign trade, from the balance of payments to interests. Therefore, this analysis calculates the result of COVID-19 to sports and tourism business for affected countries within the worldwide. Thus, this study evaluated the impact tourism performance to detect the economic changes in sports industry.
  • Publication
    Investigation of solar energy production by Photovoltaic (PV) system using rooftop coating as passive cooling technique at Bukit Tinggi, Malaysia
    (Semarak Ilmu Publishing, 2025-04)
    Ahmad Zaidi Abdullah
    ;
    Nurhafiza Azizan
    ;
    Nurul Atiqah Kadir
    ;
    Nurul Nadirah Mohd Hussin
    Solar power energy is known as one of the popular renewable energies that has been studied by many researchers all over the world. Photovoltaic (PV) panels are used to produce electricity directly from the sunlight. Cooling is a very important technique used in the PV system industry. This is because the heat generated by the PV system can reduce its performance, resulting in higher costs. The cooling technique consists of two types: active cooling technique and passive cooling technique. In this investigation, the passive cooling technique is selected. This is due to its advantages such as less maintenance, did not require large space and affordable. The nanocoating method is a widely used as passive cooling method for glass and PV panels. However, this investigation is carried out to investigate the rooftop coating integrated with PV panels system at Bukit Tinggi due to the limited previous research found worldwide. M168 coating is applied to the rooftop and the effects on the PV systems have been investigated. Two sets of On-Grid Connected PV systems were set up; where each system consists of two inverters were set up to analyze the output. The results then were recorded. According to the investigation results, the PV system with a coated rooftop generates a higher voltage of 249.80V and total power production difference of 16% compared to the PV system with an uncoated rooftop. Although the temperature for coated rooftop PV system quite higher than the uncoated rooftop PV system at the beginning, then the temperature constantly lower than the uncoated rooftop PV system. This study can be used as a guideline for PV system passive cooling methods at Bukit Tinggi.
  • Publication
    On-site partial discharge measurements and characterisation using Rogowski coil for insulation condition monitoring in medium voltage cable
    ( 2020)
    Ahmad Zaidi Abdullah
    This thesis presents an on-site partial discharge (PD) measurement tools which is one of the best methods in providing early detection before the occurrence of power breakdown in the major part of electrical distribution system. The repetition of PD operation at the defect site could cause insulation breakdown as the defect would extends until it crosses the electrodes between the insulation, and ended up with the entire network breakdown. In this study, an on-site PD measurement has been conducted at eight substation that used 11 kV cross link polyethylene (XLPE) underground power cables in order to assess the insulation condition that is based on the International Electro-technical Committee (IEC) 60270 standard. As insulation failure usually begins with PD activities, which is not only one of the primary reasons to cause the deterioration of the cable insulation, but also the characteristic scalar to describe the condition of cable insulation. Thus, IEC, IEEE and CIGRE propose PD diagnosis as an appropriate tool for determining the properties of the condition of cable insulation. In order to study the PD characteristics of the typical defects in XLPE power cable, four characteristics as rise time, zero crossing, peak amplitude and resonant frequency in main insulation were analysed based on the PD measurement established.The Rogowski coil (RC) has been developed and used as a PD measuring sensor in this measurement. In order to figure out the capability of the proposed measurement technique, the 11 kV distribution network with real parameters has been modelled using Electromagnetic Transient Program-Alternative Transient Program (EMTP-ATP). Next, the denoising process is based on Discreate Wavelet Transform (DWT) technique that has been conducted to discriminate between the interference noise and PD signal from the measured data. From the work conducted, it was found that, the technique and the RC sensor had indicated good significance for the PD measurement in both modelling and in on-site situations. Based on the on-site measurement results, it shows a similar PD pattern between the techniques conducted as compared to the conventional technique, which is recently practiced by electrical utility company. For the denoising technique, the Daubechies level 2 is found to be the best mother wavelet as compared to Symlet and Coiflet mother wavelets based on the analysis conducted. The characteristics of PD signal founded in this work within range 200 MHz are important in providing a good guideline for PD measurement activities in power cables especially during the utility maintenance work in the future. Additionally, the innovative portable PD monitoring system, which is integrated with the RC sensor, provides a reliable system for early detection prior to power breakdown in the electrical distribution system in the future.
      11  2
  • Publication
    Partial discharge signal measurement based on stand-alone and hybrid detection technique for power transformer
    ( 2020-01-01)
    Jalil M.A.A.
    ;
    Afifah Shuhada Rosmi
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Muzamir Isa
    ;
    Auni W.N.
    ;
    Ahmad Zaidi Abdullah
    ;
    Aizam M.T.
    Partial discharge (PD) is a phenomenon that causes failures in high voltage (HV) components due to the degradation of insulation. Before an interruption or fault occurs, early detection of insulation degradation is essential. However, the long-term effect of PD will lead to the failure of the power system. This is important to control and diagnose the health of the HV power equipment such as power transformer. The main issue when measuring PD is the accuracy and sensitivity of the PD detection technique. This paper consists of two parts which are classification of the PD detection technique and hybrid detection technique. In this paper, an overview of the detection technique for power transformer including optical detection, chemical detection, electrical detection, electromagnetic detection, acoustic emission detection and hybrid detection technique is presented. The hybrid detection technique is based on combining two or more stand-alone detection technique. Based on this review, the hybrid detection technique showed that the advantages of performance in terms of sensitivity and accuracy for detecting the PD in power transformer.
      1  36
  • Publication
    Measurement and Identification of Partial Discharge in 11kV XLPE Cable Jointing
    ( 2023-01-01)
    Jamalil S.A.S.
    ;
    Ahmad Zaidi Abdullah
    ;
    Hamzah M.H.
    ;
    Bohari Z.H.
    The reliability of power networks can be compromised by failures in cable connections, which are often caused by poor insulation quality. The use of different insulating materials during the connection process can result in defects, leading to partial discharge (PD) in high voltage equipment. PD measurements using a Rogowski Coil sensor and a high-efficiency Oscilloscope, following the IEC-60270 guidelines, are a widely recognized method for evaluating the quality of insulation systems. Experimental measurement was performed at university high voltage laboratory. This paper focuses on measuring PDs in extension (joint) cables, where they typically occur, specifically in 11kV XLPE jointing cables, and comparing them with ordinary cables without jointing. The project aims to analyze PD signal characteristics and identify partial discharge patterns in the time and frequency domains using MATLAB.
      1  20
  • Publication
    Review Study of Image De-Noising on Digital Image Processing and Applications
    ( 2023-03-01)
    Abdulah C.S.K.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Baharuddin Ismail
    ;
    Mohd Annuar Mohd Isa
    ;
    Afifah Shuhada Rosmi
    ;
    Wan Azani Wan Mustafa
    ;
    Ahmad Zaidi Abdullah
    ;
    Wan Nor Munirah Ariffin
    ;
    Jamil M.K.M.
    This paper reviews several studies of image de-noising on digital image processing and applications. Noisy images contain different noise that exist either due to environment or electronic interferences. Ergo, de-noising is crucial to eliminate the noise that disturb data collecting process. The impact of de-noising on image processing can result for accurate and precise data collected from the image. Additionally, de-noising process required several crucial steps that help to enhance knowledge on digital image and its application. Hence, study and understanding de-noising can improve multiple aspect such as image quality, data sensitivity and specificity, accuracy of the collected data, and increase the percentage of each parameter.
      1
  • Publication
    First Principles Enhanced Electronic Band Structure of Back Contact in CdTe Solar Cells using DFT+U Method
    ( 2023-01-01)
    Ahmad N.I.
    ;
    Nurhafiza Azizan
    ;
    Kar Y.B.
    ;
    Doroody C.
    ;
    Syahrun Nizam Md Arshad @ Hashim
    ;
    Ahmad Zaidi Abdullah
    ;
    Jamal A.
    Cadmium telluride (CdTe) superstrate solar cells have captivated the industry with their remarkable cost-effectiveness. However, optimizing the composition and optoelectrical properties of optimal back surface field (BSF) which can act as a lattice matching interface between the back contact and absorber layer remains a key challenge due to the work function disparity of p-CdTe with metal contacts. In this study, the influence of the Hubbard U parameter on the calculated electronic properties of ZnTe as an optimal BSF compound is presented using the density functional theory (DFT) technique. The Hubbard U value progressively increased from 1 to 4.2 to analyze its influence on the band diagram and Total Density of States (TDOS) in a full comparison of DFT and DFT+U approaches. As the value of Hubbard U increased, the band gap energy exhibited a corresponding increase from 1.20 eV to 2.24 eV, respectively. In comparison, the DFT+U approach with a value of 4.2 exhibited superior accuracy in predicting the band gap of ZnTe, yielding a value of 2.24 eV that closely approximated experimental measurements. This finding reinforces the relevance of employing Hubbard U to achieve more accurate and reliable band gap values for any material doping.
      1
  • Publication
    Analysis on Multiple Acoustic and Electrical Emission of PD Signal Based on Signal to Noise Ratio (SNR) on Power Cable
    ( 2020-12-11)
    Mohammad W.N.A.W.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Norfadilah Rosle
    ;
    Khairul Nadiah Khalid
    ;
    Afifah Shuhada Rosmi
    ;
    Ahmad Zaidi Abdullah
    ;
    Jamil M.K.M.
    Acoustic Emission (AE) and Electrical Emission (EE) partial discharge (PD) monitoring are effective methods in detection of the insulation failure in power cables. However, the unwanted noise from the surrounding environment can influence the effectiveness and accuracy of the PD measurement on the PD signal. Therefore, Discrete Wavelet Transform (DWT) denoising technique is introduced in order to suppress the disrupted noise. In this study, a different type of mother wavelet, level decomposition and its frequency spectrum on multiple AE and EE PD signals were performed via MATLAB software in order to analyze the performance of denoising technique. These PD signals were deal with white noise and Discrete spectral interference (DWT). The better performance of denoising technique is based on evaluating the maximum value of Signal to Noise Ratio (SNR) in order to find the optimum mother wavelet. In this case, the most optimum mother wavelets are rbio3.3 for AE and EE PD signals respectively with the highest value of SNR.
      5  39
  • Publication
    Modeling and simulation of a 16.20 kWp on-grid solar Photovoltaic System (PV) using PVSyst at Malaysia
    ( 2023-01-01)
    Kadir N.A.
    ;
    Ahmad Zaidi Abdullah
    ;
    Mohd Hussin N.N.
    Renewable energy is very useful alternative source to replace the usage of conventional energy. Solar energy is one of popular energy that has been utilised as its irradiance can generate electricity when strike with the photovoltaic solar (PV) panels. This paper presents a design and simulation of 16.20 kWp of 405W Si-mono PV system connected to the grid. It is very crucial to do the simulation in order to do the analysis in terms of performance, efficiency, power losses, irradiance and other related factors. The design, operation, and maintenance of new grid-connected solar PV systems may benefit from performance analysis. PVsyst is used as the design and simulation tools for the PV solar system simulation. It was developed by the University of Geneva as a pedagogical tool to explain in detail the procedures and models used, as well as to provide an ergonomic approach to project development. The site involves is Kampung Bukit Tinggi. From the simulation results, the array nominal energy is 25.81 MWh. The output inverter energy available is 21.59 MWh which fed to the grid. The performances ratio is 80.21% due to the several losses. This study may be useful for future grid-connected design and operation.
      7  18
  • Publication
    A study on performance characteristic: The effect of different parameter of renewable energy application
    ( 2018)
    Nadia Tajudin
    ;
    M. H. Amlus
    ;
    Amlus Ibrahim
    ;
    Ahmad Zaidi Abdullah
    ;
    Ummi Naiemah Saraih
    Malaysia government still identify the best system in giving people solution on renewable energy. This study will focus on the performance of PV module. The characteristic of PV module still can be argued especially in absorbing the direct effect of sun light energy. The previous authors were not having a specific solution on the problem of the PV module implication after received the direct effect of sun light. This study will suggesting on the innovation of the process and system of PV module and restructuring the characteristic and provides information. The tools of quality PDCA and (OEE) will be used to identify the best solution using the different type of cooling system. From this information, the stake holder can decrease the cost of using this type of technology.
      2  28