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

Banana powder production via foam mat drying

Banana puree is one of the main commercial banana products available in the market worldwide. However, like other purees, banana puree deteriorates quite rapidly and gets a chilling injury when refrigerated. Therefore, this study focused on the dehydration of banana puree using a foam mat drying (FMD) technique to prolong its shelf life. It involved whipping the banana puree to form foams with the help of whey protein concentrate (WPC) and carboxymethyl cellulose (CMC) as the foaming agent and foam stabilizer, respectively. The study evaluated the effect of different foaming agent percentages (5, 7.5, 10, 12.5 and 15%) and drying temperatures (50, 60, 70 and 80°C) on the production of the foam mat dried banana powder. Besides that, the drying curves of banana puree using FMD and oven drying methods were compared. The banana powders produced were also analyzed in terms of the foam density, moisture content, solubility, color (browning index) and flowability (caking strength). Based on the findings, the FMD technique has proven to produce a good quality banana powder better than the control sample especially at a higher foaming agent concentration (15%) and drying temperature (80°C). By using the FMD technique, the banana puree has the capacity to be dried three times faster compared to the conventional oven drying method to form a more stable banana powder

Issues and Challenges in Voltage Uprating for Sustainable Power Operation: A Case Study of a 132 kV Transmission Line System in Malaysia

Ageing grid infrastructure is a critical issue that is currently faced by electrical utilities worldwide, resulting in crucial decisions that must be made for the replacement, repair, or refurbishment of assets under constrained budgetary conditions, as well as other factors. As one of the fastest-developing countries globally, Malaysia is steadily growing in terms of its cumulative population, large industries, and advanced transportation sector, leading to an increasing electricity demand and, consequently, putting stress on electric utility providers to meet these tremendous demands. Significant concerns in the new development of transmission in Malaysia are the environmental issues, which involve exploration in gazetted areas and forest reserves. This paper describes the issues and challenges in developing a new transmission line system in Malaysia. In recent years, uprating existing transmission line systems has been one of the best asset management decisions for electric utility operators in order to meet such a demand for capacity. This paper assesses the technical issues and conventional methods of uprating the voltage of an existing transmission line system. The initial study found that the phase-to-Earth clearance does not fulfil the electrical clearance envelope. The study on the existing 132 kV transmission line system further analysed these issues and proposed an appropriate technique for uprating to a 275 kV transmission line system. Finally, the results indicate that the voltage uprating of the 132 kV transmission line system to 275 kV is able to satisfy the electrical clearance requirement envelope

Breakdown characteristics and dielectric properties of palm oil and coconut oil based tio2 nanofluids

The increasing concerns on environmental issues have led to the introduction of vegetable oils such as Palm Oil (PO) and Coconut Oil (CO) as potential candidates for alternative dielectric insulating fluids for mineral oil. Even though the overall performances of these oils are comparable with other types of vegetable oils, some improvements can be carried out especially on their electrical properties. Extensive electrical examinations need to be conducted on these PO and CO at laboratory level in order to determine its feasibility for practical application in transformers. This work presents an examination on the electrical properties of PO and CO under the presence of a semi-conductive nanoparticle, Titanium (IV) Oxide (TiO2). Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein was used in this study, whereas the volume concentrations of TiO2 used are from 0.001% to 0.050%. Investigation on the effects of a surfactant, Cetrimonium Bromide (CTAB) was also carried out. Transmission Electron Microscope (TEM) was used to examine the morphology of RBDPO and CO based TiO2 nanofluid. Moreover, AC and lightning breakdown voltages, dielectric dissipation factor, relative permittivity and resistivity measurements were taken whereas the withstand voltages for AC and lightning were statistically evaluated through Weibull distribution. This study found that the AC breakdown voltages of the RBDPO and CO can be increased through introduction of TiO2 without CTAB where the highest percentages of increments are 17.2% and 22.7% respectively. The AC breakdown voltage of RBDPO and CO based TiO2 nanofluid can however decrease with introduction of CTAB. The effect of TiO2 on the lightning breakdown voltages of RBDPO and CO under both fields is quite small for samples with or without CTAB where the highest percentages of increments are 9.2% and 11.3% respectively. The dielectric dissipation factors and resistivity of RBDPO and CO based TiO2 nanofluid are significantly affected by the presence of CTAB whereas TiO2 has no significant effect on the relative permittivity of RBDPO and CO for samples with and without CTAB. The statistical analysis reveal that the AC breakdown voltages at 1% probability for RBDPO and CO have experienced a significant improvement after the introduction of TiO2 regardless with or without CTAB where the highest percentages of increments are 63.9% and 36.8% respectively. On the other hand, TiO2 has small effect on improving the lightning breakdown voltages at 1% probability under non-uniform field regardless with or without CTAB. Significant improvements of the lightning breakdown voltages at 1% probability under quasi uniform field are found for samples with CTAB

Systematic approaches and analyses on voltage uprating of 132 kV transmission lines: a case study in Malaysia

With the ageing infrastructure and fast-growing demand faced by utilities worldwide, voltage uprating is one of the most effective solutions and strategic approaches in asset management decisions. In this study, a systematic voltage uprating method is used to propose the new voltage level, based on the existing transmission lines’ physical structure, by utilising appropriate techniques. Prior to work conducted, the existing 132 kV transmission line was first examined in terms of the clearances and the components attached, and a technical issue on the clearance under still air was found to be a significant concern, particularly on phase-to-earth arrangements. Next, the proposed techniques and processes, by increasing the insulation strength and improving air conductor clearances, were used for the individual existing 132 kV transmission tower. The proposed voltage uprating of the 132 kV transmission tower comprehensively examines phase-to-earth under normal and extreme wind conditions based on electrical clearance requirements for 275 kV transmission lines. The proposed uprating model was then simulated using the Finite Element Method (FEM)-based commercial software under several lightning conditions, i.e., various basic lightning insulation levels (BIL) and different flashover mechanisms, taking into consideration still air and wind conditions for the voltage profile and its insulation strength analyses. The study found that the voltage profile condition for the proposed voltage uprating model was able to withstand its BIL under all conditions and thus satisfied the electrical requirement needed

Systematic Approaches and Analyses on Voltage Uprating of 132 kV Transmission Lines: A Case Study in Malaysia

With the ageing infrastructure and fast-growing demand faced by utilities worldwide, voltage uprating is one of the most effective solutions and strategic approaches in asset management decisions. In this study, a systematic voltage uprating method is used to propose the new voltage level, based on the existing transmission lines’ physical structure, by utilising appropriate techniques. Prior to work conducted, the existing 132 kV transmission line was first examined in terms of the clearances and the components attached, and a technical issue on the clearance under still air was found to be a significant concern, particularly on phase-to-earth arrangements. Next, the proposed techniques and processes, by increasing the insulation strength and improving air conductor clearances, were used for the individual existing 132 kV transmission tower. The proposed voltage uprating of the 132 kV transmission tower comprehensively examines phase-to-earth under normal and extreme wind conditions based on electrical clearance requirements for 275 kV transmission lines. The proposed uprating model was then simulated using the Finite Element Method (FEM)-based commercial software under several lightning conditions, i.e., various basic lightning insulation levels (BIL) and different flashover mechanisms, taking into consideration still air and wind conditions for the voltage profile and its insulation strength analyses. The study found that the voltage profile condition for the proposed voltage uprating model was able to withstand its BIL under all conditions and thus satisfied the electrical requirement needed

Issues and challenges in voltage uprating for sustainable power operation: a case study of a 132 kV transmission line system in Malaysia

Ageing grid infrastructure is a critical issue that is currently faced by electrical utilities worldwide, resulting in crucial decisions that must be made for the replacement, repair, or refurbishment of assets under constrained budgetary conditions, as well as other factors. As one of the fastest-developing countries globally, Malaysia is steadily growing in terms of its cumulative population, large industries, and advanced transportation sector, leading to an increasing electricity demand and, consequently, putting stress on electric utility providers to meet these tremendous demands. Significant concerns in the new development of transmission in Malaysia are the environmental issues, which involve exploration in gazetted areas and forest reserves. This paper describes the issues and challenges in developing a new transmission line system in Malaysia. In recent years, uprating existing transmission line systems has been one of the best asset management decisions for electric utility operators in order to meet such a demand for capacity. This paper assesses the technical issues and conventional methods of uprating the voltage of an existing transmission line system. The initial study found that the phase-to-Earth clearance does not fulfil the electrical clearance envelope. The study on the existing 132 kV transmission line system further analysed these issues and proposed an appropriate technique for uprating to a 275 kV transmission line system. Finally, the results indicate that the voltage uprating of the 132 kV transmission line system to 275 kV is able to satisfy the electrical clearance requirement envelope

Investigation of Insulation Characteristics of GFRP Crossarm Subjected to Lightning Transient

The advancement of material technology has contributed to the variation of high-performance composites with good electrical insulation and mechanical properties. Their usage in electrical applications has grown since then. In Malaysia, the composite made of Glass Fiber Reinforced Polymer (GFRP) has been adopted for crossarm manufacturing and has successfully served 275 kV lines for a few decades. However, the combination of extreme conditions such as lightning transient and tropical climate can impose threats to the material. These issues have become major topics of discussion among the utilities in the Southeast Asian (SEA) region, and also in previous research. In Malaysia, more than 50% of total interruptions were caused by lightning. Limited studies can be found on the composite crossarm, especially on the square tube GFRP filled crossarm used in Malaysia. Therefore, this paper proposes to study the behavior of the particular GFRP crossarm, by means of its insulation characteristics. Experimental and simulation approaches are used. Throughout the study, the GFRP specimen is known to have an average breakdown strength at 7.2 kV/mm. In addition, the CFO voltages of the crossarm at different lengths are presented, whereby the behavior under dry and wet conditions is comparably discussed. At the same time, the polarity effect on the CFO voltages is highlighted. The maximum E-fields at the immediate moment before breakdown are analyzed by adopting the finite element method (FEM). Non-uniform distribution of E-fields is witnessed at different parts of the crossarm structure. Simultaneously, the maximum field localized on the crossarm immediately before the breakdown is also presented

The behavior of polyurethane foam-filled glass-fiber-reinforced polymer crossarm subjected to lightning transient voltage

The demand for composite materials in high-voltage electrical insulation is escalating over the last decades. In the power system, the composite glass-fiber-reinforced polymer has been used as an alternative to wood and steel crossarm structures due to its superior properties. As a composite, the material is susceptible to multi-aging factors, one of which is the electrical stress caused by continuous and temporary overvoltage. In order to achieve a better insulation performance and higher life expectancy, the distribution of the stresses should firstly be studied and understood. This paper focuses on the simulation work to better understand the stress distribution of the polyurethane foam-filled glass-fiber-reinforced polymer crossarm due to the lightning transient injection. A finite-element-based simulation was carried out to investigate the behavior of the electric field and voltage distribution across the sample using an Ansys Maxwell 3D. Electrical stresses at both outer and inner surfaces of the crossarm during the peak of lightning were analyzed. Analyses on the electric field and potential distribution were performed at different parts of the crossarm and correlated to the physical characteristics and common discharge location observed during the experiment. The results of the electric field on the crossarm indicate that both the outer and internal parts of the crossarm were prone to high field stress