Partial Discharge Characterization based on Leakage Current Pulses Waveform for Contaminated Glass Insulator String

This paper deals with the analysis of partial discharge (PD) occurrences based on leakage current (LC) pulses distribution under different level of contamination. In this work, laboratory based contamination performance tests are conducted on four units of glass insulator string stacked in I-position. Results show that PD can be characterized (according to their occurrence with respect to the AC supply) as follows: corona discharge occurring dominantly in lightly contaminated insulators, surface discharge occurring dominantly in medium contaminated insulators and finally internal discharge occurring dominantly in heavily contaminated insulators. The ability to distinguish the type of PDs from the LC waveform could be used to monitor and predict the condition of the insulator. The outcome can be incorporated in a conditioning monitoring system

Evaluation of residential grid-connected photovoltaic system as the potential energy source in Malaysia

Application of solar energy in Malaysia has been started in 1998. This country has a large potential of solar energy due to its location at equatorial region. The current energy consumption and demand in Malaysia is describes in this paper. The potential of solar energy in Malaysia is described together with the suitable photovoltaic construction. It also explains the plans conducted by Malaysia involving solar energy that covers investments and also projects involved such as Malaysia Building Integrated Photovoltaic (MBIPV). Simulation of grid-connected photovoltaic system in this study is performed using HOMER software. Finally, the potential of having a grid-connected PV system in a residential area is analyzed. The positive and negative findings in terms of cost and suitability of the system are explained

Transformer Fault Early Warning System Model Using GSM Network

This paper presents the design and implementation of amobile embedded system using an Arduino microprocessor to monitorand record key operational indicators of a distribution transformer,such as transformer oil level, temperature and vibration of adistribution transformer in a substation. If there is any abnormalityor an emergency situation, the system sends SMS (Short MessageService) messages to designated mobile telephones containinginformation about the abnormality of the mentioned parameters.Providing early warning of the abnormality of the distributiontransformer can be accomplished by shutting down the entire unitwith the aid on-line monitoring system integrates with Global ServiceMobile (GSM) Modem. Furthermore, the design generally consiststand-alone single chip microcontroller, modem and sensor packageslocated on distribution transformer site. In general, the design isdeveloped for the user to easily recognize the distribution transformerthat is suffered by any high vibration and rise in temperatures andlocated in remote or suburban area which is rarely and hard to reachfor manual monitoring. The ultimate objective is to monitor thetransformer oil level and temperature of 24 hours, 7 days a weekcontinuously besides the current and voltage parameter whichincluded in basis monitoring syste

Development of an Integrated System for Ozone Treated Harvested Rainwater in Perspective of Green Building Scenario of Malaysia

In this study an integrated system for rainwater harvesting and ozone treatment has been developed for continuous supply of drinkable water. In the perspective of Malaysian scenario ozone treatment of rainwater is still considered a new approach. This pilot project is launched to justify the reliability, the effectiveness and the economic aspect of ozone treated rainwater. The samples of rainwater were analyzed for both physiochemical and microbiological parameters before and after the ozone treatment. The injection of ozone has shown prominent improvement in both parameters and also the quality up gradation of the original rainwater. The results are encouraging and suggest that the technique is promising to fulfil both requirements continuous supply of rainwater as well as accomplish successful ozone treatment. The system can readily be installed at any location and measurements assure that it could certainly provide an alternative water source when conventional piped supply is unavailable. In the perspective of Green Building scenario this integrated approach of ozone treated harvested rainwater might be able to reduce the impact of environmental factors. Keywords: Ozone treatment, Rainwater quality improvement, Water quality, Disinfection with ozone, Green building concept

Potential of Residential Grid-Connected Photovoltaic System as the Future Energy Source in Malaysia

Malaysia has started the implementation of solarenergy harvesting in 1998. Located at equatorial region, Malaysia hasa large potential for solar energy. This paper examines the currentenergy consumption and demand in Malaysia. The potential of solarenergy harvesting in Malaysia is described together with the suitablephotovoltaic construction. It also explains the plans conducted byMalaysia involving solar energy that covers investments and alsoprojects involved such as Malaysia Building Integrated Photovoltaic(MBIPV). Finally, this paper analyses the potential of having a gridconnectedPV system in a residential area. The positive and negativefindings in terms of cost and suitability of the system are explaine

Effect of broken skirts on voltage distribution along insulator strings

The existence of broken glass insulator as part of a complete string may alter the local voltage distribution. A finite element software is used to study the effect of broken glass insulator (stub) to the voltage distribution profile. In this paper we present the voltage distribution profile across single and ten units of glass insulator string with different locations. The results show that the presence of broken insulator under dry conditions and without contaminants affects the distribution profile of voltage. The local voltage distribution is certainly altered when the stub is present at any location in the string. However, maximum percentage increase in voltage is experienced when the stubs are located near to the ground (GND) end. This result helps to explain the ability of transmission line insulation system to operate satisfactorily even with the presence of stubs along the string

Compact high-voltage pulse generator for pulsed electric field applications: lab-scale development

Square wave pulses have been identified as more lethal compared to exponential decay pulses in PEF applications. This is because of the on-time which is longer causes a formidable impact on the microorganisms in the food media. To have a reliable high-voltage pulse generator, a technique of capacitor discharge was employed. Four units of capacitor rated 100 μF 1.2 kV were connected in series to produce 25 μF 4.8 kV which were used to store the energy of approximately 200 J. The energy stored was discharged via HTS 181-01-C to the load in the range of nano to microseconds of pulse duration. The maximum voltage applied was limited to 4 kV because it is a lab-scale project. The electrical circuit diagram and the development procedure, as well as experimental results, are presented

Development of Compact On-Line Partial Discharge Analyzer Assessing Nanocomposite Insulation Performance for Research Purpose

Analyzing on-line partial discharge (PD) data using commercially available spreadsheet application software like Microsoft Excel is possible but very difficult to do. The problem is because the PD data are quite long and depend on the sampling rate used during testing. Increasing the sampling rate will increase data samples in one cycle of 50 Hz waveform, and longer time is needed to analyze the data. A further problem is associated with compiling the PD data; Excel uses a large memory to run, plot and calculate the PD data for analysis purpose, and sometimes this leads to computer memory crash. Due to this problem, an alternative on-line PD analyzer (on-LPDA) needs to be developed. This paper reports on the performance of the software that was developed using LabViewTM 8.5. The result shows that the software can extract PD parameters like PD numbers, PD magnitude, and plotting PD pattern without large time and memory consumption, compared with Excel, and experiences no memory crash up to 125 mega sampling (MS) rate

Effect of Humidity on Partial Discharge Characteristics of Epoxy/Boron Nitride Nanocomposite under High Voltage Stress

Partial discharge (PD) may lead to the degradation of insulating materials and affect the lifetime of high voltage equipment. This paper describes the effect of relative humidity on PD characteristic of epoxy/boron nitride (BN) nanocomposite under high voltage (HV) stress. In this work, CIGRE Method II was utilized as an electrode configuration. BN nanofiller was chosen because of its high insulating properties with high thermal conductivity. The PD characteristics such as PD charge magnitude, PD number or occurrence, and average of PD charge during certain of ageing time under HV stress against relative humidity were examined. The results revealed that PD number of humid samples is higher about 8~14% compared to the normal ones. It is considered due to the decrease of surface resistance of the humid samples. The PD charge magnitudes of humid samples are slightly higher compared to the normal ones. The epoxy/BN nanocomposite has lesser PD number and magnitude compared to the neat epoxy samples

Partial Discharge Characteristics of Polymer Nanocomposite Materials in Electrical Insulation: A Review of Sample Preparation Techniques, Analysis Methods, Potential Applications, and Future Trends

Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends