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 economic determinants of sports industry in Malaysia
    ( 2021-07-21)
    Mohammad Harith Amlus
    ;
    Rashid I.M.A.
    ;
    Samah I.H.A.
    ;
    Nazmizan Muhammad
    ;
    Ahmad Faizal Salleh
    ;
    Ahmad Zaidi Abdullah
    Sports thought-about united of the foremost vital components in national development. Since independence in 1957, Malaysian government has place such a lot efforts and measures on sports development. Asian nation sporadically goes through periods of distress associated with sport performance. Asian nation spends plenty of cash and experience on its high performance athletes. Programs facilitate high athletes perform higher in coaching, endure injury, train the mental facet of performance, and aid athletes and coaches in alternative areas similarly. this can be cash that's well spent. Indeed, if the govt. goes to pay cash supporting sport this can be wherever these funds belong. The Malaysian tourism sector has widened its scope by venturing into extreme sports tourism. With this new development, tourism opportunities square measure created and boosting the Malaysian tourism business growth. the aim of this paper is to see the predictors of sports tourism involvement in Asian nation from the economics perspective. 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. This study evaluated the impact using supply and demand curve to detect the economic changes in tourism industry. Lastly, tourism and sports sector became an intermingled strategy for several nations to get important value. Malaysia, for instance, in its National Key Economic space (NKEA) under the tourism sector indicates international sports events as a serious economic activity to push.
  • Publication
    Development of Second Order High Frequency Filter for Partial Discharge Measurement
    ( 2024-11-01)
    Syed Akhmal Syed Jamalil
    ;
    Shamsul Z.
    ;
    Muzamir Isa
    ;
    Ahmad Zaidi Abdullah
    ;
    Nanyan A.N.
    Partial Discharge (PD) can occur on any high-voltage equipment. This study is particularly concerned with the PD that occurs on underground cables. Researchers frequently struggle to isolate interference noise from the PD signal when doing PD measurements. Therefore, to reduce the interference noise during PD measurements, Sallen-Key High Pass Filter (HPF) with a 500 kHz, or a little bit higher cut-off frequency are designed. This filter is designed with a designated cut-off frequency value because the frequency range of the PD signal is between 1 MHz to 1 GHz. Based on the results of experimental testing for actual filters, the designed filter is a HPF with a cut-off frequency of 500 kHz. When the generator function's input frequency values are set between 500 kHz and 2.4 MHz, the signal will pass the filter and provide output values for both frequencies and amplitude. However, at frequencies lower than 500 kHz, the signal is beginning to be filtered and the output signal's amplitude is getting close to zero. Based on the PD testing results, there is interference on the PD signal shown on the oscilloscope when a 1kV supply is applied to an underground cable without using a filter. But, when the proposed filter is used in PD testing, the ripple voltage is reduced from 123 mV to 67 mV. This proves that when the designed HPF is used in PD testing, it can reduce interference noise on the PD signal.
  • Publication
    The magnetic flux density of various geometries of Rogowski Coil for overvoltage measurements
    ( 2020-01-01)
    Ayob Nazmy Nanyan
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Muzamir Isa
    ;
    Afifah Shuhada Rosmi
    ;
    Ahmad Zaidi Abdullah
    ;
    Baharuddin Ismail
    ;
    Haziah Abdul Hamid
    Overvoltage phenomenon is the common problem that always occurs in the power system and can cause the electrical system network breakdown, and in some cases, it may explode. The frequent overvoltage also can affect and degrade the lifespan of the electrical power system components and network. Thus, the overvoltage sensor is needed to overcome this problem matter. The Rogowski coil (RC) is one of an inductive coil group, and it is suitable for measuring the alternating current (AC) and transient currents or overvoltage. This paper demonstrated the effect of RC magnetic flux density, B with difference cross-section, geometries sizing and the number of turns by using Finite Element Method (FEM). Commonly, there are three types of RC widely used; rectangular, circular and oval. Each of these cross-sections has different characteristics in term of performance. The results have shown that the rectangular cross-section is better than oval and circular cross-section based on the number of magnetic flux density.
  • Publication
    Dynamic Partial Discharge Characteristic for Onsite Measurement Based on Zero Crossing in Power Cable
    ( 2022-01-01)
    Ahmad Zaidi Abdullah
    ;
    Bohari Z.H.
    ;
    Nurhafiza Azizan
    ;
    Muzamir Isa
    This paper analyzed the dynamic Partial discharge (PD) characteristic for onsite measurement based on zero crossing in high voltage power cable. According to IEC60270, high voltage measurement characteristic is required to identify correct PD signal. There is currently limited research operating on the trait, especially zero crossing, and because of this, comprehensive PD detection characteristics need to be further established in certain severe conditions. This occurrence has an erratic and sporadic characteristic that is challenging to identify. This paper explored the time of zero crossing for onsite measured PD signal for power cable through MATLAB simulation. This task is crucial to choose the range of zero crossing time based on the highest peak of detected PD signal. Based on the detailed analysis, it is substantially identified that there is an specific time only for PD signal with the highest amplitude, and based on detected times, a range of zero crossing characteristic was described for PD signal. It provided a useful analysis result for the guideline during onsite PD measurement for power cable.
  • 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
    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.
  • Publication
    Partial Discharge Rise Time Characteristic based on Experimental Measurement in Power Cable
    ( 2023-01-01)
    Hashim M.H.
    ;
    Ahmad Zaidi Abdullah
    ;
    Syahrun Nizam Md Arshad @ Hashim
    ;
    Muzamir Isa
    ;
    Jamal A.
    ;
    Aziza N.
    This study presents a comprehensive investigation into the rise time characteristics of partial discharges (PD) in cable insulation through experimental measurements. Partial discharges are a critical phenomenon in high-voltage systems, serving as an early indicator of insulation degradation. Understanding the rise time of partial discharges is essential for assessing the severity of insulation defects and ensuring the reliability of power cable systems. The experimental setup involved controlled conditions to induce partial discharges in cable samples, allowing for precise measurement and analysis of the rise time. The study explores the correlation between rise time and different factors such as cable design, insulation material, and defect type. Results indicate that the rise time of partial discharges exhibits distinct patterns based on these factors, providing valuable insights into the nature of insulation defects. The findings contribute to the development of effective diagnostic tools for condition monitoring in power cable systems, ultimately enhancing the reliability and safety of electrical infrastructure.
  • Publication
    Evaluation on innovation approaches on performance from Malaysian perspective: A study on Malaysian Building energy saving
    ( 2018)
    M. H. Amlus
    ;
    Amlus Ibrahim
    ;
    Ahmad Zaidi Abdullah
    ;
    Nurhafiza Azizan
    ;
    Ummi Naiemah Saraih
    Lately Malaysia energy consumption versus generation rapidly shows increasing due to increasing of load. This phenomenon happened following to advanced country development. Lacking on design and without energy management approach the energy consumption and monthly electrical bill will steadily increased and support the increasing of world carbon emission. Therefore the aim of this work is to approach the simplest innovation task-energy audit , which is load-apportioning strategy. This approach using matching the usage of equipment with fully utilized space and reschedules the time of usage. A one week data was collected by logged power meter at main switchboard at selected building using Fluke Power Recorder. From the data collected, current usage of every load can be determine, then load will be arrange into a group with same portion and same time of usage. The result shows clearly the energy consumption for every single day and indicates the highest and lowest peak. From this work the apportioning strategy implemented by rearrange the load following type of room application. After the arrangement, new measurement was taken and a very good result was established. This work also can be further apply for a huge load that can be save a lot of money for owner especially government by energy saving.
  • 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.
  • 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.
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