Now showing 1 - 10 of 12
  • Publication
    Analysis of space charge formation in LDPE in the presence of crosslinking byproducts
    ( 2012-02) ;
    George Chen
    Cross-linking byproducts are suspected to be the main contributing factor in space charge formation observed in XLPE. To investigate the mechanism behind this phenomenon, low density polyethylene was soaked into three main crosslinking byproducts, acetophenone, α- methylstyrene and cumyl alcohol, and space charge measurements were performed using the Pulse Electroacoustic technique (PEA). It has been found that soaking LDPE in cumyl alcohol introduces more charges into the system, with homocharges and heterocharges accumulating within the sample compared to the additive free sample. In contrast, α- methylstyrene and acetophenone reduce the amount of accumulated charges. In terms of charge decay, all three byproducts enhance the decay process in the insulator. Further investigations were conducted in conditions where two byproducts are present in a sample. The results shows that acetophenone is a dominant byproduct in determining the charge density patter built up during the charging process, whilst the rate of charge decay is observed to be high in the presence of α-methylstyrene in the sample.
  • Publication
    Electric field and space charge distribution in propylene carbonate under continuous DC electric field using Kerr effect
    (Iran University of Science and Technology, 2025-06) ; ; ; ;
    P. L. Lewin
    ;
    T. Andritsch
    The study investigates the electric field and space charge distributions in propylene carbonate under direct current (DC) applied fields using Kerr effect. Propylene carbonate is known for its high permittivity and is utilised in many applications, including electrochemical systems and dielectric materials. Understanding the behaviour of electric fields and space charge distributions within propylene carbonate is critical for optimising its performance in these applications. In the study, Kerr effect is employed which by applying the DC electric field across the test liquid for measuring the electric field and space charge distributions within the propylene carbonate. The experimental setup involved a controlled application of DC fields, and the Kerr effect measurements were conducted using an optical system. The results show significant understandings into the behaviour of space charges and their influence on the electric field distribution in propylene carbonate. Distinct patterns of charge accumulation and electric field distortion were observed and analysed in the dielectric liquid properties and charge transport mechanisms. The relationship between electric fields and space charges in propylene carbonate under DC conditions has been provided by the findings. The study also shows that the Kerr effect is a useful tool for studying electric field distributions in complex materials.
  • Publication
    Experimental Investigation on Thermal Conductivity of Palm Oil and Zinc Oxide PFAE-based Nanofluids
    Vegetable oil (VO) have been constantly researched as an alternative to the conventional mineral oil (MO) in the application of transformer insulation liquid. VO is deemed as a suitable replacement for MO as they are a renewable source, cheaper in price, and have a high thermal conductivity, high flashpoint, and high breakdown voltage value. In addition, the trending interest in nanofluids has made it possible to further improved the insulating properties of VOs. This paper reports the experimental results of thermal conductivity test of Palm oil-based nanofluids and Palm fatty acid ester (PFAE)-based nanofluids. The nanoparticles used in this work is Zinc Oxide (ZnO) <50nm nano powder and the nanofluid (NF) samples are varied by low, medium and high concentrations. The test was conducted at 9 different temperatures from 25°C to 65°C with 5°C gap. The result shows that a low and medium concentration nanofluid has an improvement in thermal conductivity value, up to 42.6% and 59.5% respectively for palm oil-based nanofluid. Meanwhile, the high concentration palm oil-based nanofluid has lower enhancement in thermal conductivity value at certain temperatures. As for PFAE-based nanofluids, the thermal conductivity value has improved by up to 27% and 14.4% for medium and high concentration respectively. Nanofluids with medium concentration of ZnO, has the highest enhancement in insulating and cooling properties for both palm oil and PFAE-based nanofluids. This observation is supported by the kinematic viscosity value of the mentioned nanofluid.
      7  26
  • Publication
    Preparation of vegetable oil-based nanofluid and studies on its insulating property: A review
    ( 2020-01-07)
    Ainanie Azizie N.
    ;
    The application of vegetable oil as an insulating fluid is gaining a lot of interest from researchers all over the world because of the fact that it is a renewable source and is easily available. This paper reviews and compares the preparation methods of vegetable oil-based nanofluids that have been used by many different authors. The experimental results obtained by previous researchers on the insulating properties of the vegetable oil-based nanofluids are also analysed and discussed in detail. In addition, future improvements for experimental works with insulating nanofluids are also proposed.
      1  18
  • Publication
    The effect of semi-conductive and non-conductive nano particles in sunflower oil based insulation
    ( 2020-01-07) ;
    Kwong Yeaw L.
    ;
    ;
    Kamarol Mohd Jamil M.
    ;
    ; ;
    Ainanie Azizie N.
    Following the improvement of technology, more and more alternatives are introduced to improve the insulation material and one of them is the nanotechnology. Research had been done which confirm the enhancement of the transformer oil upon adding nanoparticles in term of dielectric strength, viscosity, relative permittivity and others. In this research, semi-conductive (ZnO) and non-conductive (ZrO2) nanoparticles with weigh to volume ratio of 0.05g/l are added to the sunflower oil based insulation and the effects are observed. The relative permittivity of added ZnO is higher compare to ZrO2 in mineral oil. The situation is opposite as ZrO2 yield higher permittivity with sunflower oil. In term of breakdown voltage, the addition of ZnO shows a better dielectric strength compare to ZrO2. The kinematic viscosity is also increase when both nanoparticles are added in which ZnO contributes a higher value.
      1  43
  • Publication
    Flashover voltage prediction on polluted cup-pin the insulators under polluted conditions
    ( 2021-01-01)
    Salem A.A.
    ;
    Abd-Rahman R.
    ;
    Kamarudin M.S.
    ;
    Othman N.A.
    ;
    Jamail N.A.M.
    ;
    ; ;
    Rawi I.M.
    The natural pollution which is mainly affected by the weather conditions are the main cause of flashovers on high voltage insulators leading to outages in power systems. In this work, characteristics of flashover for contaminated cup-pin insulators have been studied based on experiential test and a mathematical model. Information from laboratory test combined with new mathematical model results are used to define Artificial Neural Network (ANN) algorithm and Adaptive Neuro-fuzzy Inference System (ANFIS) for calculated the flashover characteristics (current IF and voltage UF). several of experiments and measurement are carried out for 1:1, 5:1, 10:1 and 15:1 ratios of bottom to top surface salt deposit density on contaminated samples (z). Dimensional Analysis Method (DAM) was used to derive new model for the variables which often effective in the flashover phenomenon of polluted insulators. The model was derived by establishment the relationship between flashover voltage UF and current IF, length of pollution layer LP, exposure time t, arc constant A and layer pollution conductivity of insulator σ. The both arc constants A and n is computed using genetic algorithm. Comparative investigates have clearly shown that the approach AI-based method gives the agreeable results compared to the mathematical model.
      3  27
  • Publication
    The simulation analysis of piezoelectric transducer with multi-array configuration
    ( 2020-01-07)
    Ahmad Kamil Zainal Abidin N.
    ;
    ;
    Azizan, Muhammad Mokhzaini
    ;
    ; ;
    Azli N.A.
    ;
    Nordin N.M.
    Low frequency energy harvesting using piezoelectric is one of promising method on harvesting energy from a free source. This method offered powering low load and remote device application. However, due to its nature which is inconsistency in providing the magnitude of input, specifically in low frequency harvesting, better solution to stable up and increase the converted output is explored widely. There are a few parameter that influences in the piezoelectric output generation. These parameter includes the type of piezoelectric, piezoelectric array configuration, AC-DC converter and etc. The types of the piezoelectric used in this project are the circular piezoelectric. When there is a force (motion) exerted on the piezoelectric disk, electrical charge was produced which initiated the energy conversion. In this research, the configuration of array connection for piezoelectric were investigated. The system is tested with different load configuration in a range of 10 kΩ to 1 MΩ. The design and development of the piezoelectric array variant were series (S), parallel(P), series parallel (SP) and parallel-series (PS). The observation emphasized on finding the best types of piezoelectric array configuration in producing optimum output of the harvested power. The simulation part consists of designing, simulating and analysing the result are done by using PSIM software. For validation of the simulation result, the implementation design of the hardware prototype that supplies pressure to piezoelectric have been done. In conclusion, a proper implementation of piezoelectric array configuration will produce optimum power output which can fulfil the minimum requirement of energy for powering low load device.
      1  34
  • Publication
    Effect of Pollution Distribution Scenarioes on Flashover Characteristics on Outdoor Insulators
    ( 2020-09-27)
    Salem A.A.
    ;
    Abd-Rahman R.
    ;
    Al-Ameri S.
    ;
    Kamarudin M.S.
    ;
    Jamail N.A.M.
    ;
    ;
    Zainuddin H.
    ;
    Soomro D.M.
    ;
    Mizad M.
    Distribution of the contamination on insulators is often irregular, which threatens the reliability of outdoor insulation. This work aimed to study the influence of pollution distribution, humidity and dry band location with various scenarioes on flashover characteristic of insulators. Flashover tests of cup-pin glass polluted insulators were conducted. Findings indicated the difference between the flashover performances of insulators under different pollution distribution. The flashover characteristics like voltage and current are greatly affected by salt deposit density (SDD), distribution modes, and distribution area. The relation between U50 and SDD has positive power function with more contrast in distribution. Insulators with more regular distribution have lowest flashover voltage and highest critical leakage current. Different distribution modes lead to the change of the conductivity of the contamination layer and the uneven distribution of the current density, which is the main cause that the characteristics of pollution flashover are directly related to the pollution modes.
      3  32
  • Publication
    Optimum Sizing and Performance of Fuel Cell Stack Integrated by Boosted DC-DC converter for Running DC Load
    (Institute of Physics, 2022-01-01) ; ;
    Suhelmi
    ;
    Iswandi
    ;
    Azis A.
    ;
    Rimbawati
    ;
    Leow W.Z.
    ;
    Jufrizal
    A fuel cell stack (FCS) converts the chemical energy to be the electrical energy through an electrochemical process. One type of FCS is proton exchange membrane (PEM) with hydrogen and oxygen as the main chemical energy source. The PEMFCS has been applied widely for operating direct current (DC) loads. However, the optimum sizing of FCS, DC load and the other supported devices are not considered well, thus the system performance does not have function optimum fully. This paper present the FCS integrated by boosted DC-DC converter for running DC load. The optimum sizing of FCS and boosted DC-DC converter are explained to obtain the required number of FCS and boosted DC-DC converter. A simulation of the FCS integrated boosted DC-DC converter is conducted using SIMULINK MATLAB. The simulation results show that the FCS and boosted DC-DC converter have good performance in the operation of DC load.
      2  3
  • Publication
    Modelling of Wireless Power Transfer System Using MATLAB SIMULINK
    (Institute of Electrical and Electronics Engineers Inc., 2022-01-01) ;
    Nugraha Y.T.
    ;
    ;
    Nisza I.
    ;
    Perangin-Angin D.
    ;
    Alam H.
    Wireless power transfer (WPT) is a concept to transfer electrical power from a sending coil to a receiving coil without wire. The previous researchers have studied about the WPT using its implementation in simulation modelling, but it is little supporting that related to the mathematical formulation, especially in the distance between the sending and receiving coil. This paper presents a simulation modelling of WPT system using MATLAB SIMULINK based on the mathematical formulation that related to the inductance of inductor of the sending and receiving coil, turn number of coil and mutual inductance as representative of the distance between the sending and receiving coil. The simulation results show that 5 kHz pulse wave generated by pulse generator drives the gate terminal of MOSFET that converts the DC voltage to be 5 kHz AC voltage on the sending coil by the half bridge inverter circuit. The sending coil generates its rms AC voltage of 46.87 V for the distance of 50 cm and also an AC voltage is inducted on the receiving coil with its rms voltage, current and power are 22.79 V, 2.15 A and 10.68 W, respectively.
      2  3