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Berbagai kajian dan penelitian telah dilakukan terhadap pembangkitan plasma ozon menggunakan Metode Dielectric Barrier Discharge (DBD) dengan kondisi plasma non termal. Metode DBD memiliki berbagai keunggulan seperti distribusi medan listrik yang seragam pada penghalang dielektrik dalam menghasilkan plasma. Dalam studi ini, aplikasi COMSOL Multiphysics digunakan untuk melakukan pemeriksaan plasma ozon dari Ozone Chamber - yang terdiri dari elektroda plat aluminium berlubang dengan salah satu elektroda konfigurasi berlubang yang dipisahkan oleh dielektrik kaca tunggal. Perangkat lunak COMSOL Multiphysics memiliki Modul Plasma yang mencakup parameter elektrostatis, difusi drift, dan transportasi spesies berat untuk menghasilkan pelepasan pada O2 murni dengan keluaran konsentrasi ozon plasma. Dari hasil analisis simulasi diperoleh konsentrasi ozon tertinggi sebesar 3710,476 ppm pada tegangan masukan 8 kV dan konsentrasi terendah sebesar 3682,598 pada tegangan masukan 5 kV. Hal tersebut menunjukkan bahwa tegangan yang diberikan pada elektroda memiliki korelasi linier dengan konsentrasi ozon yang dihasilkan.

Ozone generation using screw-type electrodes with different distance peak to peak was studied, with the view to comparing the effectiveness of the two technologies in improving for high ozone concentration. Current density, heat flux, and distribution electric potential were performed by using simulation software Ansys. These simulations indicate that the screw-type electrode with a distance of 2 mm generates the higher current density, the result is the same as the initial assumption that the screw distance 2 mm will be better than distance 1.5 mm because it has lower heat flux. Experimental work confirms that a screw model with a distance of 2 mm also has high ozone concentration than a distance 1.5 mm screw model due to current density making electric field strength also higher to produce high ozone concentration, as was also noted by previous authors.

Silica nanofiller or nanosilica is known to be one of the most widely used fillers in polymer nanocomposite. Nevertheless, agglomeration of nanosilica within polymer matrix has been discovered to be a limitation towards enhancing the insulating properties. With this regard, plasma discharge is found to have a great potential in overcoming the agglomeration of nanofiller despite using chemical solvents or coupling agents. The effectiveness of plasma treatment in functionalizing the nanofiller is influenced by few factors, including treatment duration. However, the optimum treatment duration is still yet to be explored to determine its effect on the morphology characteristic of nanofiller. Therefore, this study investigates the effect of plasma treatment duration on nanosilica by varying the treatment times to 1, 3, and 5 minutes. The glow mechanism of plasma discharge is produced by exhilarating the plasma reactor with 0.5 kV and 20 kHz of source parameters. The characteristics of plasma discharge are analyzed according to the discharge current and the properties of the Q-V Lissajous figure. In comparison, the morphology of nanosilica is characterized by using a Perkin Elmer FTIR spectrometer. The result showed that the plasma treatment duration is proportional to the intensity of the hydroxyl group functionalized on the nanosilica morphology with the highest intensity at 5 minutes of treatment time.

Cold plasma with glow discharge mechanism exhibiting a uniform ionization process when a background gas passes through the discharge region of the plasma reactor under a certain optimum configuration of input parameters. A glow discharge is a homogeneous and effective mechanism of cold plasma for industrial applications due to the continuous and stable discharge process compared to the filamentary discharge. Meanwhile, the development of glow discharge plasma operated under atmospheric pressure condition is indispensable to overcome the weaknesses of filamentary discharge plasma, such as the nonuniform and discontinuous discharge process. The discharge mechanism is essentially dependent upon the input parameters of the plasma system, such as the amplitude of the voltage supply, the operating frequency, and the flow rate of the background gas. In this paper, the effects of voltage supply on plasma discharge characteristics produced from the plasma jet reactor with the high-voltage electrode are discussed. The value of voltage supply is tuned to be suitable with the discharge gap, frequency supply, and background gas flow rate in producing the homogeneous glow plasma discharge. The characteristics of the glow plasma discharge produced are analyzed based on the pattern of the charge-voltage Lissajous figure and time-domain discharge current techniques. Results show that the most efficient and uniform plasma is disclosed by the configuration of input parameters such as 0.5 kV of supply voltage, 20 kHz of operating frequency, and 0.8 L/min of purified helium gas flow rate. The parallelogram-like Lissajous figure obtained indicating the homogeneous plasma discharge with a constant value of discharge capacitance.

The partial discharge and dielectric breakdown strength characteristics are among the parameters measured for insulation development, especially for the power cable. Cross-linked polyethylene (XLPE) is a type of host polymer used widely to insulate the conductor part of the medium and high voltage cables. The resilience of the cable commonly depends on the performance of the polymer to insulate the conduction part efficiently. However, the dielectric performances of the XLPE degraded due to various aging factors. Adding the nanofillers into the XLPE matrix might enhance the dielectrics properties of the XLPE. In this study, silica (SiO2) nanofillers have been added into the XLPE matrix with various loadings to improve the partial discharge and dielectric breakdown strength. The loadings of the silica nanofillers were varied at 1, 3, and 5 wt% to identify the most effective nanofillers loading in improving XLPE nanocomposites' durability. The results show that XLPE nanocomposites with 1 wt% silica nanofillers obtained the lowest value of the maximum PD magnitude compared to other compositions. The dielectric breakdown strength of XLPE increased significantly as 1 wt% of silica nanofillers have dispersed. However, the trend was saturated when the nanofiller loading at 3 wt% and slightly decreased at 5 wt% of the nanofiller loading.

Ozone is a robust antimicrobial agent with numerous potential applications in the industry. Ozone, in either gaseous or aqueous phases is effective against the majority of microorganisms. Relatively low concentrations of ozone and short contact time are sufficient to inactivate bacteria and microorganism. This project investigates the efficacy of dissolved ozone against food-related microorganism. The ozone system is evaluated using the microbial effects on Staphylococcus aureus, and Bacillus cereus and determine its clinical efficacy against ORP level for disinfection application. Results showed that 100% of S. aureus and B. cereus were eliminated by the dissolved ozone in tap water. In conclusions, the dissolved ozone has great efficacy, lower cost and less time disinfection cycle. Thus, this low temperature, ozone-based disinfection is a green technique and is regarded as one of the most promising disinfection techniques.

Sterilization is essential for inactivation of microorganisms. There are many methods of sterilization, such as the use of heat or chemical processes. However, some equipment can be damaged by heat and can only be sterilized at low temperatures. Failure to properly disinfect or sterilize equipment may lead to transmission via contaminated objects. This paper presents a sterilization process using ozonized water at a temperature of 29.5°C with gram-negative bacteria (Escherichia coli). The antibacterial effect was examined with various concentrations of ORP (oxidation reduction potential) at 702 mV, 802 mV, 940 mV, 950 mV, and 960 mV. A strong linear correlation was observed between ORP value and the surface area of the antibacterial effect. It was found that increasing the concentration of ORP affects the surface area of Escherichia coli.

Many approaches to improve the transformer oil characteristics have been made by adding nanofillers into the liquids, but it has caused the existence of sedimentation and agglomeration thereby resulting in incompatibility of transformer oil. In view of foregoing, this paper aims to study the impact of cetyl trimethyl ammonium bromide (CTAB) surfactant added with the nanofiller in improving the compatibility and agglomeration issues towards improvement of breakdown voltage (BDV) characteristics of oil nanofluids. This study was carried out by implementing three different percentages of silica (SiO2) and alumina (Al2O3) nanofillers along with CTAB as surfactant into the mineral oil. The breakdown voltage test was carried out accordance to IEC 60156 standard. The results show that the inclusion of 0.1 wt% SiO2 and 0.1 wt% Al2O3 nanoparticles into mineral oil have improved the BDV. Meanwhile, Al2O3 nanofluids with 0.075 wt% CTAB had good impact on BDV but not on SiO2. This case has reverse behavior with the sedimentation which 0.1 wt% CTAB in SiO2 nanofluids has a good response but not the whole in Al2O3 nanofluids. This could be mainly due to the limitation stability of the nanofluids.

In this study, multiwalled carbon nanotubes (MWCNTs) were modified using low frequency (50 Hz) nonequilibrium plasma, which was generated separately by oxygen and nitrogen dielectric barrier discharge plasma (DBD) at atmospheric pressure. The MWCNTs were treated with oxygen and nitrogen DBD plasma at atmospheric pressure under three different applied voltages, because the MWCNTs surface was closely related to the plasma treatment voltage. The surface and electrical properties of pristine and treated MWCNTs were studied using Transmission Electron Microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, while the electrical characteristics were measured using a Hall measurement and two-point probe. FTIR showed formation of oxygen-containing groups like C=O and COOH for the O2 DBD plasma, and addition of N–H vibration bending for the N2 DBD plasma. Raman spectroscopy revealed that the ratio of I D/I G increased with increasing discharge voltage of plasma. The ascended I D/I G may be ascribed to the production of several new defects owing to the introduction of oxygen- and nitrogen functional groups recognized by FTIR. The results of Hall measurement showed that the hall mobility increased with the increase of O2 and N2 DBD voltage. Highest hall mobility was measured for MWCNTs treated with nitrogen at 12 kV, which was 172.9 cm2/Vs. It was also found from the two-point probe IV curve that Ohmic behaviour of pristine MWCNTs tended to change to Schottky behaviour after DBD plasma treatment.

This paper presents the simulation of circuit-based horizontally oriented grounding electrodes with the consideration of frequency dependence of soil resistivity and permittivity. The frequency dependent circuit parameters were determined by the equations given by Sunde and Dwight, while the frequency dependent properties (soil resistivity and relative permittivity) were modeled according to Scott model. Results obtained show that the voltage response is highly affected by the soil resistivity, especially at high soil resistivity value, which in this study, the highest value is 2000 Ωm. This work also considers the front time of the current to study the effect of current front time to the response, and it was found that the faster the current front time, the more significant difference of peak voltage between frequency dependent and frequency independent models is obtained. Obviously, the current circuit-based model (frequency independent model) tends to provide overestimated results. Therefore, the effect of frequency on the soil resistivity and relative permittivity should not be neglected when determining the transient performance of grounding electrode in order to obtain accurate results.

Maintenance of high voltage equipment is vital in order to detect an early partial discharge (PD) activity. PD based on IEC 60270 standard is defined as a localized electrical discharge that occurs between conductors and it only partially bridges the insulation. Nowadays, a commercial high-frequency current transformer (HFCT) has been used widely as a current transducer to detect and measure the PD current. However, commercial HFCT is very expensive in the market and quite heavy due to a large size. This paper presents a development of low-cost HFCT using ferrite core with a few benefits such as low cost, lightweight and also has a wide operating bandwidth which is suitable in detecting PD. Due to it is an iron-cored, it has also offered a higher sensitivity which makes the PD measurement more accurate. Two configurations of the developed HFCT with the different number of turns at the secondary side which are 7 turns and 12 turns were presented to analyze the higher sensitivity for PD detection. Based on the obtained results of PD measurement between two configurations of developed HFCT, the developed HFCT with the lower number of turn had more appropriate results as it provided higher sensitivity and wider bandwidth.

This paper investigates the characteristics of the ultra-high frequency (UHF) and Very High Frequency (VHF) emissions that associate with negative narrow bipolar events (NBEs) which occurred within reversal distance, drev of the base station. The UHF emissions were captured by using a parallel plates antenna with its center frequency at 0.97 GHz and 20 MHz bandwidth. There are thirteen samples whereby their VHF and FF signals were leaded by their corresponding UHF about (102.25 ± 125.48) ns and (692.13 ± 382.36) ns respectively. All the UHF were found to behave like continuous bursting while some of the VHF consisted of certain periods within its burst train whereby there was no any sign of pulse during that period.

Plasma is a state of ionized gaseous substance which becomes electrically conductive to the point that having long-range of electric and magnetic fields dominate the behaviour of the substance. In addition, plasma treatment is one of the methods that can be used to improve the dispersion of nanoparticle, nanocomposite bonding, as well as the compatibility surface between polymer matrices and nanoparticle. Plasma jet is a plasma system which has been widely used in many applications especially for modification and treatment purposes. Since this method is still at an early stage of study, the specific design of plasma jet system for the purpose of nanoparticle surface treatment is still not existed yet. Therefore, the most effective plasma jet system is required to be designed and simulated in this study by concerning the plasma generation factors such as applied voltage and operating frequency. The effectiveness mechanism of plasma treatment can be promise by considering the system of plasma used as well as the classification of plasma discharge generated within 3 to 7 kV AC applied voltage and 10 to 20 kHz operating frequency. This study proposes the design and analysis of plasma jet which have been designed to obtain the most effective and efficient surface treatment process on the nanoparticle. The optimum voltage and frequency of high voltage supply to generate plasma jet are determined through simulation via COMSOL Multiphysics® software by investigating the electron density, ion density, and electron temperature produced from numerical computational. This study also involved in the measurement of plasma jet system with characteristic of plasma discharge. The results show that the most effective electron density and ion density produced throughout the ionization of working gas lies in the scale of 1018 m-3 whereas the electron temperature produced lies between 1.00 to 2.00 eV in which producing an uniform and stable glow discharge.

Ozone gas can be dissolved into water or used in the gas phase for a variety of applications. The use of ozonized water in dentistry is gaining its place in everyday dental practice. Ozone has a high oxidation potential and is 1.5 times greater than chlorine when used as an antimicrobial agent against bacteria, viruses, fungi, and protozoa. In this project, the ozonized water-based system for mouth cleansing was introduced to be able to effectively kill Bacteria, Fungi, Viruses and Parasites as well as to provide a comfortable condition to use by the patients before and after they get a treatment in a dentistry sector. The result of the study showed that the ozone-based mouth cleansing system with ORP value above 700 mV effectively killed the bacteria contained in the mouths of the patients.

This paper presents a bandpass filter using two elliptical open loop ring resonators(EOLRR) at the resonant frequency of 28 GHz. It is well suited for the next generation 5G application. Coupled resonators were developed with the expectation of pairing parasitic resonance of various degenerate modes operating close to the fundamental mode in the suggested structure of filter. The frequency response of the design is approximated using CST software. The frequency response of the filter characterizes with low insertion loss and good rejection performance. The fabrication of the EOLRRs is also easy as there is no use of via or defected ground structure. The proposed structure offers a simple and compact design while exhibiting wide stop-band characteristics Additionally, the geometrical parameters of the proposed filter design can simply tune the bands to the chosen level. The proposed EOLRRs demonstrate worthy broadband characteristics.

Partial discharge (PD) that occurs in enclosed metal equipment such as air-insulated switchgear is unpredictable and causes the failure of an insulation system. This PD emits electromagnetic field and hence can be detected through a capacitive sensor mounted on the wall. Thus, it is suitable to detect and monitor internal PD activity in an enclosed metal equipment using Transient Earth Voltage (TEV) probe. Therefore, this study aims to implementing TEV probe which has been developed at a low cost to detect the partial discharge occurs in enclosed metal equipment. It involved the characterization of the parameter of the probe and also the measurement of TEV based on IEC TS 62478 standard. In addition, the spectral density and phase-resolved partial discharge pattern of the developed TEV probe were analyzed and compared with the commercial TEV. The time-resolved pattern of the partial discharge was also recorded to monitor the PD pulses in one full cycle. As a result, it was found the partial discharge was able to be detected through this developed TEV probe with acceptable PD patterns.

Three types of data were combined together to observe the evolution of the thunderstorm at the Straits of Malacca. The first data is a collection of electric field waveforms that where captured and analyzed to obtain the flash rates. Radar images from weather radar were observed in terms of their reflectivity value and cross section to locate the active regions of a thunderstorm. Next, a lightning detection system of World Wide Lightning Location Network (WLLN) capable of capturing lightning strike locations in latitudes and longitudes where used together with all the data to observe the if lightning are present at the active region. Upon overlaying the data, an observed cloud be found that the region with high reflective value (55-60 dBz) denoted with red color, have high concentration of lightning strike from WWLLN. Combination of data will help us understand further on the behavior of the thunderstorm.

Optical fiber based on the polymer coating is one of the best options for water detection sensors in liquid insulation. The water diffusion can be simulated through the finite-element method (FEM) as it provides the finite element analysis to determine the performance of the moisture sensor based on optical fibers. In this work, a commercial COMSOL Multiphysics software was used for the FEM simulation of the coated optical fiber based moisture sensor. The response of the sensor was estimated for different thickness to select the coating thickness before the hardware design to opt for the best sensitivity. The electric field propagation used the 2D model and was estimated by using the boundary mode analysis and frequency domain study. Transport dilute species uses 3D model species to study the diffusion of water into the polymer by varying the thickness and concentration of water (mol/m3). The light propagation was simulated based on electromagnetic fields and water diffusion using Fick's law. The modelling of the sensor was done, and the response time required for the sensor was estimated along with the effect of the electric field with varying thickness of PVAc coating.

This paper presents the non-thermal plasma exhaust for removal of NOx from diesel engines vehicle. The most optimum geometric properties were used in the study for the most effective performance of the exhaust. The non-thermal plasma system was developed by using high intensity discharge (HID) ballast with 23 kV AC striking voltage. The experimental work was compared with the simulation in term of the percentage of NOx reduction. The result showed that the percentage reduction of NOx from simulation and experimental study was 68.06% and 74.37% respectively. In addition, an analysis on the recorded experimental data clearly showed that the non-thermal plasma chamber reached the maximum level of NOx removal after 24 minutes operation with the rate of increasing of 1.4321 per cent per minutes. In conclusion, the non-thermal plasma chamber provided effective treatment in terms of oxidation process to remove NOx from diesel or heavy vehicle engines.

This paper study and investigates the characteristic and relationship between lightning occurrence and temperature due to global warming. The correlation between global warming and lightning occurrence are not much in-depth study in Malaysia. The conducted of this research have been done in Kuala Lumpur and Johor Bahru, Malaysia for a period of year 2011 until year 2016 using data provided by Malaysian Meteorological Department and TNB Research. A statistical analysis between lightning occurrence and temperature have been done to show the correlational activities. It is found that there is positive correlation between temperature and lightning density in both cities. Findings of this project is useful to utility companies and electrical consultants in Malaysia in designing, and enhancing their lightning protection system for better improvement and will benefit the public in the sense of educating and understanding the importance of environmental preservation and conservation to help reduce the impact of global warming.

This paper reports the investigation of partial discharge (PD) characteristics of the plasma treated Boron Nitride (BN) nanoparticles by using atmospheric pressure plasma (APP) discharge in order to enhance the interaction between the nanofiller with the low density polyethylene (LDPE) matrices. With different loading levels of BN nanofiller (1, 3 and 5 wt%) was added into the LDPE, the phase resolved PD behavior of the untreated and plasma treated BN/LDPE nanocompoistes were measured based on IEC 60270 standard. Fourier Transform Infrared (FTIR) Spectroscopy analysis was used to characterize the chemical structures of nanoparticles and nanocomposites sample. The results showed that the inclusion of plasma treated BN could improve the PD resistant properties of the nanocomposites compared to the untreated BN/LDPE nanocomposites due to the increased of the hydroxyl groups after the plasma treatment.

The growing number in human population leads to an increasing number of patients worldwide. Therefore, the facilities in the hospital needs to be improved to cater the higher number of operations that need to be conducted. The current method used to sterilize the surgical equipment is separated between heat sensitive equipment and non-heat sensitive equipment. Our vision is to develop a low temperature sterilizer machine that can be used to sterilize both heat sensitive and non-heat sensitive equipment in one sterilizer machine. Thus, it can save money and time to sterilize the medical equipment. In this work, the ozone-based surgical equipment sterilizer system was successfully developed and effectively killed the bacteria from used medical equipment.

Partial discharge (PD) detection in high voltage equipment is a vital solution for the identification of insulation degradation. It is a regular strategy of detecting the PD by acoustic emission using conventional methods like piezoelectric transducers (PZT) but this method has drawbacks such as low sensitivity and false alarms due to electromagnetic interference (EMI). In order to avoid these kinds of drawbacks, a thin polymer film based Single-mode fiber (SMF) – multimode fiber (MMF) – single-mode fiber (SMS) was fabricated and studied. The thin polymer film SMS sensor was tested with two types of light source; Broadband source (BBS) and Tunable laser source (TLS). The experiment has been carried out with air ultrasonic transmitter and high voltage source for creating PD to detect the acoustic signal generated. The signal to noise ratio (SNR) of both sensors was observed and measured. The PD signal detection was carried out in air medium and the phase-resolved partial discharge patterns were recorded and the performance was compared with the conventional measuring instrument. The acoustic signals have been detected by the sensor generated from the transmitter and surface discharge using BBS and TLS. Identification of the best light source for PD detection has been explained.

Lightning locating system (LLS) is useful for public to warn them as soon as the sensors detect the lightning strike. A common LLS uses various detection techniques such as time difference of arrival (TDOA), magnetic direction finding (MDF) and interferometry. Using MDF method, the direction of the horizontal component of the magnetic field generated by the lightning flash was obtained by magnetic crossed loops. Two vertical and orthogonal loops with planes oriented NS (north-south) and EW (east-west) were used, each to measure the magnetic field to obtain the direction of the source. Loop antennas are low frequency receiving sensors using in applications such as oil exploration, geophysical research, and survival communications. The loop antennas are sensitive to the magnetic field, but not the electric field. The incoming magnetic field induces voltage in the loop antenna. The induced voltage is proportional to the area of the loop (A), multiplied by the derivative of the magnetic field component perpendicular to the area of the loop. Cross loop antenna consists of two orthogonal magnetic loops. By measuring the induced voltage at each loop, the component of the magnetic field can be obtained. This research investigates the implementation a three-station MDF based system.

Study about characteristics of Very-High Frequency (VHF) and microwave radiation emitted by lightning discharge process focusing on the first return stroke and its subsidiary pulses from negative cloud-to-ground (-CG) flash is reported in this paper. The lightning measurement is conducted by using air-gap parallel plate antenna with a bandwidth of 20 MHz and resonant frequency around 1 GHz with remote sensing application. The recorded VHF and microwave radiation waveform are analyzed based on the reference waveform which is the Fast E-field Antenna (FA). The pulse duration of the subsidiary pulses is between 11.991 μs and 16.253 μs. The peak amplitude of VHF radiation impulse is between 59.14% and 75.34% larger than the peak amplitude of the microwave radiation impulses. The characteristics of the VHF and microwave waveforms of the first return stoke and its subsidiary pulses A, B and C are oscillating noise-like bursts. The highest peak amplitude of VHF and microwave radiation impulses is during the subsidiary pulse C.

The role of the grounding system in the safety of the power system and protection of personnel is obvious during an unexpected short circuit or lightning discharge at the substation. The aim of this work is to analyze the effects of several parameters: lightning impulse front time, soil resistivity and types of grid materials on the grounding system of the Substation. The ground potential rise (GPR), touch voltage and step voltage of a 50 m x 60 m grounding grid buried at a depth of 0.5 m were computed using CDEGS when injected by impulse with different front times. Results show that the shorter the front time of lightning impulse waveform, the higher the value of GPR, touch voltage and step voltage. Meanwhile, when the value of soil resistivity is increased, the value of GPR, touch voltage and step voltage is also increased. Lastly, different types of grid conductor materials give different values of GPR, touch voltage and step voltage. However, it can be said that the differences are too small to be of any significance.

Electrical treeing is one of the main reasons for long-term degradation of high voltage insulation especially in the cable accessory which commonly made from silicone rubber due to non-uniformly structures of the cable accessories. Recently, the combination of nanofillers with the silicone rubber matrix can reduce the possibility of the electrical treeing to grow further by changing its patterns and slow-down its propagation. However, the influences of nanofillers on the tree hindrance and its patterns are not well understood. This paper explores the influence of nanofiller on tree pattern in silicon rubber. The electrical tree patterns were characterized using fractal analysis. The box-counting method was used to measure the fractal dimension and lacunarity to obtain the structure of the tree pattern during the electrical tree growth. The structure of the electrical tree in silicone rubber nanocomposites has higher fractal dimension and lacunarity. Sample with nanofiller possesses dominant fractal dimension of tree growth compared to the sample without nanofiller.

This article presents a study on electrical treeing performances with its associated partial discharge (PD) and the influence of filler concentration in silicone rubber (SiR) samples which are filled with silicon dioxide (SiO2) and silicon nitride (Si3N4) as nanofillers for electrical tree growth suppression. There are many researches on electrical treeing in SiR with SiO2 nanofillers but none of the publication have reported on Si3N4 nanofillers for suppression of the electrical tree growth. In this study, the treeing experiments were conducted by applying a fixed AC voltage of 10 kV and 12 kV at power frequency of 50 Hz on unfilled SiR, SiR/SiO2, and SiR/Si3N4 nanocomposites with different filler concentrations by 1, 3, and 5 weight percentage (wt%) and the electrical treeing parameters were observed with its correlated PD patterns. The outcome from this study found that the SiR/Si3N4 nanocomposites were able to withstand the electrical treeing better than the pure SiR or SiR/SiO2 nanocomposites. Furthermore, the increase in filler concentration improved the electrical tree performances of the nanocomposites. This finding suggests the Si3N4 can be used as filler in polymeric insulating materials for electrical tree inhibition. Meanwhile, the PD activity shows increment when the tree progresses thereby indicating correlation in both parameters which can be as key parameter for monitoring unseen electrical treeing in the opaque samples.

This paper presents comparative study on electrical treeing with its associated partial discharge (PD) grown in silicone rubber (SiR) samples having different concentration of silicon dioxide (SiO 2 ) and silicon nitride (Si 3 N 4 ) nanofillers. Despite many studies on electrical treeing in SiR with SiO 2 nanofillers, none of the publication have reported on Si 3 N 4 nanofillers for the purpose of the electrical tree growth suppression. By applying a fixed AC voltage of 12 kV at power frequency of 50 Hz, the treeing experiments were conducted on unfilled SiR, SiR/SiO 2 , and SiR/Si 3 N 4 nanocomposites with 1, 3, and 5 weight percentages (wt%) of filler weight concentration and the treeing parameters were observed together with its correlated PD patterns. This study found that among the samples of SiR, SiR/SiO 2 and SiR/Si 3 N 4 , the best nanocomposites to suppress the electrical tree growth is SiR/Si 3 N 4 . Moreover, when the electrical treeing progresses, the PD activity shows increment thus indicating correlation in both parameters which can be a key tool for monitoring unseen treeing in opaque samples.

This paper investigates the effect of cold plasma on the germination, growth, and yield of corn plant. The effect of plasma plume was applied to the corn seeds to kill the bacteria on the outer surface of the seeds to investigate the effects of cold plasma towards the germination and growth rate of the seeds. The time of treatment was varied from 3, 5 and 10 minutes to identify the optimum treatment time. The result showed that the seeds that treated with 3 minutes plasma treatment germinates faster and show excellent growth rate compared to the untreated seed. This revealed that cold plasma treatment as an alternative method to promote seed germination and enhance seed growth of the corn plant.

Nanocomposites have been actively studied in recent years as an insulating material due to their excellent in electrical, mechanical and thermal properties. Even though, the addition of nanoparticles into polymer matrices showed better performance in relation to partial discharge (PD) and AC breakdown strength tests. However, the introduction of nanoparticles could lead to the formation of agglomeration of the fillers which may nullify the true capabilities of the composites. Therefore, silane coupling agent was introduced for surface functionalization treatment of the nano filler but among the issues associated are toxicity and complexity. In the present study, atmospheric pressure plasma is proposed to enhance the surface functionalization of the nano filler. This proposed method was used to treat the nanosilica (SiO 2 ) surfaces to enhance the interfacial interaction between the host (LDPE) and nano filler. SiO 2 nano filler was added into the LDPE at weight percentages of 1, 3 and 5%. The phase-resolved PD behaviour and Weibull analysis of AC breakdown strength of untreated and plasma-treated LDPE nanocomposites were measured to evaluate the performance of the samples. As results, the plasma treated LDPE nanocomposites experience apparent increments of the PD resistance and AC breakdown strength as compared to the untreated nanocomposites. It is implied that the plasma treatment of nanosilica has contributed to the enhancement of the filler dispersion and eventually reducing the agglomeration.

One of the high-voltage applications that are widely used is ozone generation. Research on ozone generations have been carried out for many years such as by using Dielectric Barrier Discharge (DBD) method to produce optimum ozone. This paper presents a variation of pattern and cavity diameter of perforated aluminium used as electrodes for ozone generation using a DBD method with single barrier glass. The result of the study showed that although 99.9% concentration of pure oxygen was used, the pattern variations and the cavity diameter of the perforated aluminium affected the ozone concentration. The highest ozone concentration was 2175.8 ppm in a chamber with electrode area of 99.58% (A2 electrode) and at 18 kV. The lowest ozone concentration was 567.5 ppm with 98.33% electrode area (A1) and at 17 kV. For stability of ozone concentration, the chamber with B2 electrode and at voltage 17 kV or 18 kV showed that the stability of ozone concentrations improved more rapidly.

This paper presents the simulation case study of non-thermal plasma for removal of nitrogen oxide, NOx from diesel engine vehicle. The geometric properties of the exhaust chamber are analyzed and discussed in order to obtain the most effective geometric properties of exhaust chamber that will help the process of NOx reduction become more effective. The gap between the exhaust case and perforated metal, the length of the exhaust chamber, no. of stages, hole diameter of the perforated metal and the thickness of the perforated metal are studied in details. The method used to study these geometric properties of the exhaust chamber is mesh and boundary condition. Optimum NOx reduction is achieved using exhaust chamber gap between 45mm and exhaust chamber length of 190mm with NOx reduction by 61.11%. Maximum NOx reduction is achieved by using 3 stages of the exhaust chamber with reduction by 70.63%. In addition, the hole diameter of the perforated metal with 5 mm and 1 mm of thickness are the most effective geometric properties of the perforated metal that will produce a high speed of gaseous inside the exhaust chamber and uniform speed of flow in the exit duct.

This paper proposes a simple construction of a low-cost air-core Rogowski coil (RC) sensor to measure PD pulse current by investigating the effect of winding turn number. In this study, the characteristic of the designed RC sensor was identified using Vector Network Analyser (VNA) prior to PD measurement in the laboratory. The selection of a suitable number of turns of winding for the RC has been identified to produce an optimal design of the sensor. The experimented performance of RC was compared and validated with a commercial ferrite-core high frequency current transformer (HFCT). Moreover, linear regression statistical methods have been used to validate the performance similarity between both sensors. This comparison shows a positive linear relationship and hence, validating the constructed RC with higher turn number was more suitable for PD detection.

Partial discharges (PD) occur in high voltage equipment are considered as major problem that required to be prevented to avoid any breakdown, damage and loss from happening. In addition, this pre-breakdown phenomenon can be detected using appropriate sensors such as acoustic emission sensor. In this study, acoustic emission sensor was chosen as the method to detect the PD in high voltage insulation. Low-cost piezoelectric transducer (PZT) with pre-amplifier and optical fiber sensor (OFS) were used as a sensing device to detect PD but OFS was expected to highlight its usage towards PD detection. Development of optical fiber sensor (OFS) based on Single Mode-Multi Mode-Single Mode (SMS) structure which implementing a Multimode Interference effects (MMI) was focused on. PD measurement test was conducted according to IEC 60270 and IEC TS 62478 standards. A coated SMS based OFS was fabricated and then was used in PD measurement test. Furthermore, after implementing the pre-amplified PZT sensor and coated OFS in PD measurement test, results were compared with a measuring impedance by analyzing the Phase Resolved Partial Discharge (PRPD) patterns. From the results, all sensors can detect PD as accurately as the MI but the usage of pre-amplifier on PZT has shown a great deal of advantage in removing noises and amplifying small signal, but the SMS coated OFS has shown similar ability in detecting the PD.

In this work, a set of experiments has been conducted using arc discharge Methane decomposition attempting to obtain carbonaceous materials (C-strands) formed between graphite electrodes. The current-voltage (I-V) characteristics of the fabricated C-strands have been investigated in the presence and absence of two different gases, NO2 and CO2. The results reveal that the current passing through the carbon films increases when the concentrations of gases are increased from 200 to 800 ppm. This phenomenon is a result of conductance changes and can be employed in sensing applications such as gas sensors.

Structure, chemical, and physical properties of Multiwalled Carbon Nanotubes (MWCNTs) after modification by dielectric barrier discharge (DBD) at atmospheric pressure is investigated using Transmission Electron Microscopy (TEM), Raman and Uv-vis-NIR spectroscopy. Effects of plasma treatment time on MWCNTs are analyzed. TEM result shows that during the short period of plasma treatment time of 5 minutes, the tube surface experienced a few damages. With increase in plasma treatment time, the tube surface is damaged to a certain extent. Intensity ratio, ID/IG through Raman analysis shows a good agreement with TEM. The values of ID/IG of the modified MWCNTs are larger than those of pristine MWCNTs. An increase of ID/IG indicates that considerable defects are produced on the surfaces of MWCNTs. The treated MWCNTs has energy band gap compared to zero band gap of untreated MWCNTs. It is believed that the defect site of MWCNTs can modify the electronics properties of MWCNTs from being metallic to semiconducting structure, which is applicable for almost all electronics device applications.

A lightning monitoring system is used to observe, collect and analyse lightning activities so that a preventive measure to protect power equipment from severe damage can be planned. An effective lightning monitoring system is crucial to ensure the reliability and sustainability of the electrical energy supply. Despite numerous published papers on this topic, there seem to be an absence of comprehensive review papers that evaluate monitoring technologies and their performances. Owing to the literature gap, this paper is written to summarise the working principles of the relevant sensors and the various methods of data transmission, storage and analysis, as well as the various ways of predicting the occurrence of lightning strikes. This knowledge will contribute to the development of a new online lightning detection system that will be more efficient, without reducing the effectiveness and sensitivity of the system, by utilizing the available technology for data transmission and analysis.

Sulphur hexafluoride (SFo) gas insulated switchgear (GIS) is widely used in electrical power supply system and therefore needs regular preventive maintenance. In this research work, a reliable and effective diagnostic technique was used to detect SFo byproducts caused by partial discharge (PD) occuring as a result of more that one defect, named as a hybrid defect. A 0.2-MPa presurrised coaxial chamber prototype similar to that used in GIS was used to simulate the decomposition of SFo when partially discharging at 48 kV. Two hybrid defects, namely a protrusion-floating particle and a void-floating, were used. The corresponding detected byproducts using Fourier transform infrared spectrometer are SO2, HF, SOF2, SO2F2, SO2F10, SiF4, CO, and C2F6 for the former, and C3F8 and C2F6 for the later. It was found that the by-product combination together with the by-product concentration can be correlated to the type of hybrid defect. Results also show that the protrusion-floating particle hybrid can be potentially more harmful than the void-floating hybrid.

Polymer nanocomposites have been identified to possess superior electrical insulation properties compared to its base polymer. However, weak interfacial interaction between the nanoparticles and the host polymer matrices would result in poor insulation properties. In this study, the surfaces of Boron Nitride (BN) nanoparticles were treated with atmospheric pressure plasma discharge to strengthen the interface between the low density polyethylene (LDPE) matrices and BN nanoparticles. Furthermore, AC breakdown strengths of the untreated and treated LDPE nanocomposites were measured according to ASTM D149 standard. The obtained results were analyzed with 2-parameter Weilbull distribution. Moreover, the treated and untreated nanocomposites were characterized using Fourier Transform Infrared (FTIR) Spectroscopy in order to characterize the functional groups in LDPE nanocomposite samples after subjected to plasma discharges. It is shown that hydrogen bonds are created in the functional groups of the plasma treated LDPE nanocomposites. The results also show that the AC breakdown strength of plasma treated LDPE nanocomposites sample was improved compared with the untreated LDPE nanocomposites.

Gas insulated switchgear assumes an indispensable equipment for high voltage transmission of electrical energy because of its focal points of high unwavering quality and execution, smaller in measurements and extraordinary compatibility with the environment. It utilizes sulphur hexafluoride gas as its insulant and coolant in view of its high dielectric quality and superb circular segment extinguishing capacity. Gas insulated switchgear in operation suffers the challenge of its insulation deterioration that leads to its failure due to the activities of partial discharge that is caused by defects. This failure is calamitous and it will prompt to whole power out stage that will affect all classes of human exercises. In order to monitor the condition of GIS, in this studies a simulated coaxial decomposition chamber was designed and used to simulate the decomposition of SF6 under the effect of fixed copper (Cu) and aluminium (Al) foil metallic artificial defect on the surface of the spacer in the chamber at the pressure of 0.2MPa when energizing with high voltage for a period of about 50 hours. The decomposition products of Cu and Al foil fixed defects detected offline by FTIR spectrometer are HF, SOF2, SOF4, SO 2 F 2 , SO 2 F 10 , SiF 4 , SO 2 , CO, C 2 F 6 , CF 4 and SO 2 , SO 2 F2, C 3 F 8 and C 2 F 6 respectively. These decomposed products and its concentration identify the type and the magnitude of fault in switchgear (contamination fault) and it shows that Cu fixed defect is more harmful to GIS than fixed Al foil defect.

Nanofluids have been identified to be one of the suitable approaches to increase the breakdown strength of transformer oil. However, the nanofluids tend to form sediment which nullifies its full capabilities in increasing the electrical properties such as higher AC breakdown strength. In view of foregoing, this paper presents an approach to enhance the AC breakdown strength of the transformer oil by using plasma treated silica nanoparticles to form plasma treated nanofluids. The surface of silica nanoparticle was functionalized by using atmospheric pressure plasma discharge to enhance the interfacial interaction in order to improve the sedimentation issue in nanofluids. Plasma treated nanoparticles with desired surface functionality can strongly interact with liquid molecules with better dispersed into the base fluid to form a stable suspension. The AC breakdown strength of oil samples before and after surface modification of nanoparticles were measured accordance to IEC 60156 standard. Based on obtained results, it was found that the plasma treated nanofluids had higher AC breakdown voltage compared to the pure oil and the untreated nanofluids.

Grounding system plays very important role in AC substation station for person and equipment safety. Proper design of grounding system is achievable by following IEEE Std-80 on safety in AC substation grounding but novice professionals find it not easy to use. The advantage of this paper presents evaluation of grounding system for AC substation by case studies presentation thus easing the understanding of IEEE Std-80 and its usage. This was carried out by using homegrown Sub-ground software with capability to identify the safety status of a grounding system design procedures. The grounding system is evaluated with six different cases. Different parameter is changed in each case to observe the result of the grounding system. The result shows that there are several important parameters in designing a grounding system. The parameters are grounding grid size, number of parallel rod, level of fault current, crush rock layer, cross sectional area of ground rod and level of soil resistivity. The tolerable and calculated step and touch voltage as well as the mesh voltage of the grounding system are presented in manner to tutor novice professionals on AC grounding system design. Last but not least the software developed in the laboratory useful for novice professionals training for AC substation grounding system.

A reliable diagnostic technique of Gas insulated switchgear condition monitoring is used in this research for the detection of Sulphur hexafluoride gas (SF6) decomposition products due to its high sensitivity and anti-electromagnetic interference; it is known as decomposition by-product method. A simulated coaxial decomposition chamber was designed and used to simulate the decomposition of SF6 under the effect of fixed metallic artificial defect on the surface of the spacer at the pressure of 0.2MPa when the chamber is energized at a 45KV experimental voltage over the period of 30 hours due to the presence of partial discharge caused by the artificial defect. The decomposition products (HF, SOF 2 , SOF 4 , SO 2 F 2 , SO 2 F 10 , SiF 4 , SO 2 , CO, C 2 F 6 and CF 4 ) were detected offline by FTIR spectrometer. These decomposed products and its concentration can be used detect and identify the type and the level of fault in switchgear (contamination fault) before failure for purpose of preventive maintenance.

Water is a basic human need in everyday life. However in some areas consumable clean water is still unattainable. There is an urgent need for water purification equipment. Several researches on water purification devices has been carried out with different methods. One of the methods amongst them is using the Dielectric Barrier Discharge Reactors. This method applies appropriate temperatures to make it safe for use. This paper discusses about the various methods used in water purification. The previous researchers discussed a lot about the parameters of the ozone producing capability. They also explained the characteristics and effects of voltage related to voltage sources. Furthermore, the factor of non-potable water is also used as a research material. Based on these previous researches, the researcher reviewed and investigated two of the types of electrodes used - The screw and helix type. They were examined in the same reactor tube length, thickness and tube material dimensions.

Partial discharge (PD) is an electrical release or spark that occurs between two conducting electrodes that are not bridging, and it can occur at any points in the insulation system. PDs emit electromagnetic field radiation in the frequency range of 300 MHz to 1.5 GHz. Thus, it is more appropriate to detect and monitor partial discharge using an ultra-wideband antenna which offers more accuracy than the narrowband antenna. This paper proposes the design and implementation of a microstrip patch antenna which has been designed to possess wider detection performance of ultra-high frequency (UHF) PD signal. The PD spectra of the designed UWB antenna and the commercial whip antenna was compared and analyzed. The result shows that the UWB antenna can effectively detect the UHF PD signals that occur between two electrodes. As results, it is implied that PD measurement by using designed UWB antenna is found to suitable to detect the PD signals for online monitoring of high voltage equipment.