Zaini Yaakub

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.

Development of palm - based neopentyl glycol diester as dielectric fluid and its thermal aging performance

The potential of palm-based neopentyl glycol diester as dielectric insulating fluid was investigated. The details of the transesterification of high oleic palm oil methyl ester (POME) with neopentyl glycol (NPG) with the final product yield of more than 90 wt% of NPG diester were discussed. The thermal aging performance of NPG diester was compared with conventional mineral insulating oil at 90, 110 and 130 °C. This paper focused mainly in the effects of aging to chemical, physical and electrical properties of NPG diester. Apart from being fully biodegradable and non-toxic, the synthesized diesters exhibited high flashpoint and the breakdown voltage was comparable to mineral oil. The result indicated that throughout the aging period, NPG diester exhibited lower acid value than mineral oil and no significant change in viscosity was observed. The study on mechanical properties of insulating paper aged in NPG diester shows higher tensile strength than paper aged in mineral oil. The synthesized esters have shown great potential to be used as transformer oil.

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).

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.

Ageing Study of Palm Oil and Coconut Oil in the Presence of Insulation Paper for Transformers Application

This paper presents a sealed ageing study of palm oil (PO) and coconut oil (CO) in the presence of insulation paper. The type of PO under study is refined, bleached, and deodorized palm oil (RBDPO) olein. Three different variations of RBDPO and one sample of CO are aged at temperatures of 90 °C, 110 °C, and 130 °C. The properties of RBDPO and CO as well as paper under ageing are then analysed through dielectric and physicochemical measurements. It is found that the effect of ageing is not significant on the alternating current (AC) breakdown voltages and relative permittivities of RBDPO and CO. There is a slight increment trend of the resistivity for CO, while for all of the RBDPO, the resistivity slightly decreases as the ageing progresses. Only CO shows an apparent reduction of the dielectric dissipation factor. Throughout the ageing time, the acidities of all of the RBDPO and CO remain at low level, while the moisture in oils decreases. The tensile index (TI) of the papers for all of the RBDPO and CO retain more than 50% of the TI. A significant increment of the paper ageing rates of all of the RBDPO and CO is observed at an ageing temperature of 130 °C.

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.

Palm-Based Neopentyl Glycol Diester: A Potential Green Insulating Oil

BACKGROUND The transesterification of high oleic palm oil methyl ester (HOPME) with neopentyl glycol (NPG) has been investigated. The present study revealed the application of low-pressure technology as a new synthesis method to produce NPG diesters. Single variable optimization and response surface methodology (RSM) were implemented to optimize the experimental conditions to achieve the maximum composition (wt%) of NPG diesters. OBJECTIVE The main objective of this study was to optimize the production of NPG diesters and to characterize the optimized esters with typical chemical, physical and electrical properties to study its potential as insulating oil. METHODS The transesterification reaction between HOPME and NPG was conducted in a 1L three-neck flask reactor at specified temperature, pressure, molar ratio and catalyst concentration. For the optimization, four factors have been studied and the diester product was characterized by using gas chromatography (GC) analysis. The synthesized esters were then characterized with typical properties of transformer oil such as flash point, pour point, viscosity and breakdown voltage and were compared with mineral insulating oil and commercial NPG dioleate. For formulation, different samples of NPG diesters with different concentration of pour point depressant were prepared and each sample was tested for its pour point measurement. RESULTS The optimum conditions inferred from the analyses were: molar ratio of HOPME to NPG of 2:1.3, temperature = 182°C, pressure = 0.6 mbar and catalyst concentration of 1.2%. The synthesized NPG diesters showed very important improvement in fire safety compared to mineral oil with flash point of 300°C and 155°C, respectively. NPG diesters also exhibit a relatively good viscosity of 21 cSt. The most striking observation to emerge from the data comparison with NPG diester was the breakdown voltage, which was higher than mineral oil and definitely in conformance to the IEC 61099 limit at 67.5 kV. The formulation of synthesized NPD diesters with VISCOPLEX® pour point depressant has successfully increased the pour point of NPG diester from -14°C to -48°C. CONCLUSION The reaction time for the transesterification of HOPME with NPG to produce NPG diester was successfully reduced to 1 hour from the 14 hours required in the earlier synthesis method. The main highlight of this study was the excess reactant which is no longer methyl ester but the alcohol (NPG). The optimum reaction conditions for the synthesis were molar ratio of 2:1.13 for NPG:HOPME, 182°C, 0.6 mbar and catalyst concentration of 1.2 wt%. The maximum NPG diester yield of 87 wt% was consistent with the predicted yield of 87.7 wt% obtained from RSM. The synthesized diester exhibited better insulating properties than the commercial products especially with regards to the breakdown voltage, flash point and moisture content.

A Study on the Dielectric Properties of RBDPO Olein under Low Temperature Thermal Ageing

A number of studies have been carried out previously to investigate the suitability of palm oil as dielectric insulation fluid in transformers. Among the important studies is the ageing performance of palm oil. In this paper, a study was carried out to investigate the dielectric properties of Refined Bleached and Deodorized (RBDPO) Olein after subjected to thermal ageing. A low temperature ageing was carried out at 85°C for 5 days. The AC breakdown voltage, dielectric dissipation factor, relative permittivity and resistivity of RBDPO were examined throughout the ageing duration. It was found that the RBDPO performs reasonably well under low temperature ageing.