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
    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
    A Simulation Study of Performances for Different Substrates Sizes and Copper Thickness for PD Antenna Design
    ( 2020-09-27)
    Bohari Z.H.
    ;
    Muzamir Isa
    ;
    Soh P.J.
    ;
    Ahmad Zaidi Abdullah
    ;
    Ab Rahman A.
    ;
    Nasir M.N.M.
    Partial discharge (PD) is a phenomenon that consistently happens throughout the millennium in the power equipment. This phenomenon has an unpredictable and intermittent characteristic that hard to be detected easily. There are various available methods to detect this phenomenon, but each technique has its own flaws and drawback. This paper explored the early step to select, design, and simulate a PD UHF antenna for power transformer through CST MWS simulation. This task is crucial to choose the optimized substrate size and copper thickness for the PD antenna design. Based on the detailed analysis, it is substantially proven that there is an important relationship between substrate size towards antenna performance and characteristics to design an improved and efficient PD antenna.
      1  15
  • Publication
    A Contemporary Review of High Voltage Partial Discharge Detection and Recognition Techniques
    ( 2023-07-01)
    Bohari Z.H.
    ;
    Muzamir Isa
    ;
    Faizah Abu Bakar
    ;
    Ahmad Zaidi Abdullah
    ;
    Ayob Nazmy Nanyan
    ;
    Nasir M.N.M.
    ;
    Sulaima M.F.
    ;
    Ahmad E.Z.
    This review article provides a summary of the most advanced approaches and advancements in the detection and recognition of high voltage partial discharge (PD). It discusses numerous detecting technologies, such as electrical, acoustic, and optical approaches, as well as their merits and disadvantages. It also discusses current developments in signal processing and pattern recognition algorithms used for PD detection and classification. Lastly, the study covers the challenges and limitations in high voltage PD detection and identification studies, as well as potential future solutions.
      3  31
  • Publication
    Partial discharge detection performance using multi-cylindrical slots antenna with parasitic suppression patch for power transforme
    ( 2022-01-01)
    Bohari Z.H.
    ;
    Muzamir Isa
    ;
    Ahmad Zaidi Abdullah
    ;
    Soh P.J.
    ;
    Ayob Nazmy Nanyan
    ;
    Sulaima M.F.
    This paper focused on analyzing multi-cylindrical slots performance combining with parasitic suppression patch for partial discharge detection. Both proposed slots antenna and conventional monopole are simulated using CST Microwave Studio software before being fabricated and tested with real partial discharge signal. Performance comparison will be focused on scattering parameter, radiation pattern and surface current distribution. Both antennas are subjected to a partial discharge signal from lab scaled power transformer for the field test. Based on the result, the proposed performed better in both simulation and field testing with the dual-frequency operation, with better gain improvement by 14%. For the field test, the proposed antenna generated better detection result with reduced noises by 50%.
      10  31
  • 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.
      31  7
  • Publication
    Development of detachable Rogowski Coil current sensor using PCB for High Voltage cable partial discharge measurement
    ( 2022-01-01)
    Syed Akhmal Syed Jamalil
    ;
    Muzamir Isa
    ;
    Ahmad Zaidi Abdullah
    ;
    Ayob Nazmy Nanyan
    ;
    Bohari Z.H.
    Insulation failure in High Voltage (HV) cables is evaluated using a variety of monitoring techniques. Previous silicon technologies were outperformed by wide-bandgap semiconductor power devices with faster switching speeds. Their precise current management or current protection measures must be upgraded. As a result, their precise current control or protection measures have become more sophisticated. The traditional Rogowski Coil (RC) with the magnetic core, on the other hand, has low measurement accuracy, a short measuring range, and is difficult to fabricate. This paper presents and discusses the development of a Rogowski Coil using a detachable Printed Circuit Board (PCB) as a current sensor for Partial Discharge (PD) measurement. Furthermore, the development of this innovative current sensor concentrated on the detachable PCB Rogowski Coil's capability to measure as a high-voltage (HV) current sensor and its sensitivity in fault diagnosis, over-voltage current sensing, and high-impulse current sensing on HV cables. The experimental design, techniques, and measurement parameters used in models were discussed. Finally, a brief analysis of the detachable PCB RC current sensor such as sensitivity, maximum voltage and current detection is presented. This paper can also be used as a guideline for other researchers to develop an advanced RC current sensor using PCB as a HV current sensor in the future. The measurement results of the detachable PCB RC current sensor such as the sensitivity and current detection signal can also be used as a guideline by another researcher. As a result, the goal of this project is to measure PD on HV cables using an RC current sensor by utilising PCB technology.
      2  44
  • 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.
      35  1
  • 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.
      37  2
  • Publication
    Development and Performance Analysis of the Rogowski coil sensor for Arcing Fault Measurement
    ( 2020-03-20)
    Ayob Nazmy Nanyan
    ;
    Muzamir Isa
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Haziah Abdul Hamid
    ;
    Afifah Shuhada Rosmi
    ;
    Mardianaliza Othman
    ;
    Ahmad Zaidi Abdullah
    ;
    Zamri Che Mat Kasa
    ;
    Ami Nurul Nazifah Abdullah
    Arcing fault is an overvoltage that usually occurs in the power system network, and it is necessary to monitor this phenomenon in electrical equipment. This paper presents the Rogowski coil (RC) as an arcing fault sensor. Finite element method (FEM) software used for analysing the RC magnetic flux density with two types of RC with the different turns and size demonstrated. The sizing of RC based on the 240 mm2 cross-link polyethene (XLPE) 11 kV underground cable. The prototypes of the RC sensors were designed using Solidworks software and three-dimensional (3D) printer for fabrication purposes. The main objective of the experiment is to investigate the RC effect with high magnetic flux density by implementing in real measurement. An experimental setup for real arcing fault with various voltages (up to 15 kV) was conducted to verify the RC performance, such as sensitivity and bandwidth range. The result has shown that the bandwidth of RC 1 is higher than RC 2 in all measurement by 22.6%.
      2  56
  • 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.
    ;
    Nurhafiza Azizan
    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.
      1  25