M. T. Ishak

Investigation on the Dielectric, Physical and Chemical Properties of Palm Oil and Coconut Oil under Open Thermal Ageing Condition

In this paper, a study is carried out to investigate the dielectric, physical and chemical properties of Palm Oil (PO) and Coconut Oil (CO) under open thermal ageing condition. The type of PO used in this study is Refined Bleached and Deodorized Palm Oil (RBDPO) Olein. The ageing experiment was carried out at 85 °C and 115 °C for 1, 3, 5, 7 and 14 days. Several parameters were measured such as AC breakdown voltage, dielectric dissipation factor, relative permittivity, resistivity, viscosity, moisture and acidity throughout the ageing duration. Based on the study, it is found that there are no significant changes on the AC breakdown voltages and relative permittivities for both RBDPO and CO. At ageing temperature of 115°C, there are clear reduction trends of dielectric dissipation factor for CO and resistivities for most of RBDPO. On the other hand, no clear trends are observed for viscosities, moisture and acidities of RBDPO and CO throughout the ageing duration.

Evaluation on the Lightning Breakdown Voltages of Palm Oil and Coconut Oil under Non-Uniform Field at Small Gap Distances

In recent years, there are a number of studies that have been carried out to explore the alternative for Mineral Oil (MO) as dielectric insulating fluid in transformers due to the increasing tight regulation on safety and environment. Vegetable oils have been identified as suitable candidate since it is biodegradable, non-toxic and high flash/fire points which ensure more in-service safety. Among the types of vegetable oils considered for transformers application are Palm Oil (PO) and Coconut Oil (CO). This paper presents an experimental study on the lightning breakdown voltages of PO and CO under non-uniform electric field based on needle-sphere electrodes configuration at 3 small gap distances. The type of PO used in this study is Refined Bleached and Deodorized Palm Oil (RBDPO) Olein. The main focus of this study is to examine the lightning breakdown performance of RBDPO and CO under different test conditions and assess its suitability as dielectric insulating fluid in transformers. The effect of voltage polarities (positive and negative) and testing methods (risingvoltage, up-and-down and multiple-voltage) were investigated. The data obtained from all tests were analysed by Weibull distribution in order to determine the withstand voltages for each type of oils. It was found that the breakdown voltages of RBDPO and CO are comparable with MO under positive lightning impulse. Under negative lightning impulse, the breakdown voltage of MO is slightly higher than RBDPO and CO. There is no significant effect of testing methods and voltage polarities on lightning breakdown voltages of RBDPO and CO. Based on the statistical analysis, it is found that the breakdown voltages of RBDPO and CO at 1% probability are slightly lower than MO.

Examination on the lightning breakdown strength of biodegradable oil under quasi-uniform field

Among the alternative fluids considered for application in transformers are Palm Oil (PO) and Coconut Oil (CO). Among the important studies that need to be carried out before it can be applied in-service is the lightning impulse performance. This paper presents the experimental work on the lightning impulse breakdown voltage of different PO, CO and Mineral Oil (MO). The PO used in this is the Refined Bleached Deodorized Palm Oil (RBDPO) type. The test was carried out under quasi-uniform field using sphere-sphere electrode configuration with different testing methods (rising-voltage and up-and-down). It was found that the lightning impulse performance for some of RBDPO and CO were comparable to MO.

Investigation on the lightning breakdown voltage of Palm Oil and Coconut Oil under non-uniform field

The increasing interests on the Palm Oil (PO) and Coconut Oil (CO) as a potential alternative for dielectric insulating fluid in transformers encourage a number of researches on different aspects of these oils. Among the common areas under study is the lightning breakdown voltage. In this paper, the lightning breakdown voltage of PO and CO is examined. The type of PO used in this study is Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein. The testing was carried out under non-uniform electric field using needle-sphere electrodes configuration. The influence of the testing methods, rising-voltage and up-and-down on the breakdown voltages are investigated for both types of oils. It was found that the lightning breakdown voltage performance for some of the RBDPO is comparable to Mineral Oil (MO).

Design and Optimization of UHF Partial Discharge Sensors Using FDTD Modeling

Partial discharges may occur in defective insulation systems of high voltage equipment, such as gas insulated substations and power transformers. These discharges generate electromagnetic waves that can be detected using ultrahigh frequency (UHF) sensors. UHF sensors must meet certain sensitivity criteria over a wide frequency range so as to be capable of detecting small discharges. Sensor frequency response is measured using a gigahertz transverse electromagnetic calibration system. Previous research has shown that finite-difference time-domain (FDTD) simulation of the calibration process can accurately model the response of the existing sensors. The work reported here demonstrates how a new sensor can be designed entirely using FDTD modeling. The proposed new partial discharge sensor has a physical construction that was selected to make it more robust, simple to manufacture, and convenient to install on metal-clad high-voltage apparatus. The internal structure of the UHF sensor was developed and optimized entirely within the FDTD software domain before the physical device was manufactured and tested. Simulated and experimental calibration results were found to be in agreement to within 10%. This finding validates the design methodology and optimization process. The approach described in this paper will help to streamline the design of UHF partial discharge sensors for specific applications in future.

A Study on the Lightning Impulse Breakdown Voltages of Palm Oil and Coconut Oil by Different Methods

In recent years, there have been a number of interests on the Palm Oil (PO) and Coconut Oil (CO) as a potential alternative dielectric insulating fluid in transformers which stimulate different types of studies on these oils properties. Among the important studies is the lightning impulse properties. This paper presents the investigation on the lightning impulse breakdown voltage of PO and CO under non-uniform electric field. The PO used in this study is Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein type. The influence of the testing methods, rising-voltage and up-and-down are investigated at 2 gap distances for both oils. It was found that the lightning breakdown voltage performance for some of the RBDPO and CO are comparable to MO.

A study on the dielectric properties of Palm Oil and Coconut Oil

One of the important parameter for insulating fluid is the dielectric properties. With the introduction of vegetable oil as possible alternative fluid for transformers application, it is essential to ensure this type of oil could meet the dielectric properties requirement. In this paper, a study is carried out to investigate the dielectric properties of Palm Oil (PO) and Coconut Oil (CO). The type of PO used in this study is Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein. Several parameters such as AC breakdown voltage, dielectric dissipation factor, relative permittivity and resistivity are examined for both as-received and dried samples. It was found that there are differences on the dielectric dissipation factor and resistivity between RBDPO and CO and the dielectric properties performances of all samples are improved after subjected to the drying procedure.

Electrical responses of piezoelectric device

Energy harvesting from human motion by using piezoelectric element plays an important role in the development of renewable energy technology. The energy harvesting mechanism includes the process of extracting the renewable energy, converting it into usable electricity and then storing the energy as in capacitor. Piezoelectric element is used as a sensor to convert mechanical energy into electrical energy. The electrical power supply can be used for electronic devices and other mobile applications. The element is capable in converting mechanical energy from the motion of human body, such as walking and running activities, into electrical energy. In this research, a prototype of piezoelectric energy harvesting was developed. Piezoelectric disk-type sensor was installed inside a shoe of officer cadets to harvest the mechanical force from the walking motion. The experimental work was tested for five different weights (48 kg, 59 kg, 62 kg, 71 kg, and 85 kg) of officer cadets on the treadmill with a constant speed of 2 km/h. The piezoceramics material used in this research was lead zirconate titanate (PZT). Before the piezoelectric device was tested on the cadets, the effects of single impact (free fall) of different weights (1N, 2N, 3N, 4N, and 5N) on PZT piezo disk were tested and analyzed. The responses of piezoelectric element were analyzed. The results show that the piezoelectric device generates a maximum output voltage of 7.4 V from the walking movement.

Tansig activation function (of MLP network) for cardiac abnormality detection

Heart abnormality often occurs regardless of gender, age and races. This problem sometimes does not show any symptoms and it can cause a sudden death to the patient. In general, heart abnormality is the irregular electrical activity of the heart. This paper attempts to develop a program that can detect heart abnormality activity through implementation of Multilayer Perceptron (MLP) network. A certain amount of data of the heartbeat signals from the electrocardiogram (ECG) will be used in this project to train the MLP network by using several training algorithms with Tansig activation function.

A study on the AC breakdown voltages of as-received palm oil and coconut oil under presence of TiO2

This paper presents a study on the AC breakdown voltages of Palm Oil (PO) and Coconut Oil (CO) with presence of TiO2. The type of PO used in this study is Refined, Bleached and Deodorized Palm Oil (RBDPO). TiO2 was added into RBDPO and CO at volume concentration of nanoparticles ranging from 0.001% to 0.05% In total, 50 measurements of AC breakdown voltages were recorded and analyzed by Weibull and normal distributions. Based on the test results and statistical analyses, it was found that the TiO2 could improve the AC breakdown voltages of RDBPO and CO.