Rudy Setiabudy

Physicochemical and electrical properties of jatropha curcas methyl ester oil as a substitute for mineral oil

This paper reports the investigation of jatropha curcas seeds oil as an alternative option to replace mineral oil in power transformers. This product has several advantages that recommend both its production and usage over that of other vegetable oils as crude palm oil and rape-seeds oil because it may be grown on marginal or degraded soils thus avoiding the need to utilize those more fertile soils currently being used by smallholders to grow their staple crops; and it will readily grow in areas where annual rainfall levels are significantly lower than those required by other species such as oil palm, rape-seeds oil, sunflower oil, soybeans oil, corn oil and others. For instance, these plants can be grown on all soil types in Indonesia, even on barren soil. The barren soil types can be found in many parts of eastern Indonesia that remain untapped because of the difficulty planted with other crops. Moreover, jatropha curcas oil is non-food crops. Jatropha curcas oil is processed by alkali base catalyzed esterification process using potassium hydroxide (KOH) to produce jatropha curcas methyl ester oil (JMEO) that is a product the viscosity and acidity are acceptable for high voltage equipment especially in power transformer. The physicochemical (water content, viscosity, acidity ...) and electrical (dielectric strength) properties of JMEO were measured. For comparison, we also measured breakdown voltage of mineral oil (MO) in the same experimental conditions. The obtained results show that the average AC breakdown voltages of JMEO and MO are too close.

Pre-breakdown phenomena in new vegetable oil - based jatropha curcas seeds as substitute of mineral oil in high voltage equipment

Due to their high biodegradability, non-toxicity and higher fire safety guarantee, vegetable-based oils are considered today as a potential substitute for mineral and synthetic liquids for electrical insulation and especially in high voltage power transformers. However most of known vegetable oils are derived from food materials (rape-seeds, sunflower, soybeans, palms, corns and others). And one has to be vigilant to the fact that the replacement of mineral oil by natural ester fluids based on “renewably sourced” vegetable oils, does not create new problems as this could cause global food crisis due to diversion of food into insulating material oils or others (fuel). An interesting product can be jatropha curcas oil (JCO) extracted from the fruit seeds of jatropha curcas plants (“miracle tree”) which is non-food crops. These plants can be grown on marginal or degraded soils and thus enables to avoid the need to utilize those more fertile soils currently being used by smallholders to grow their staple crops; and they readily grow in areas where annual rainfall levels are significantly lower than those required by other species such as rape-seeds, sunflower, palm, soybeans, corns and others. This paper presents an experimental study of streamers phenomena in jatropha curcas methyl ester oil (JMEO) and mineral oil (MO) under positive and negative lightning impulse voltages (1.2/50 μs); JMEO is obtained by alkali base catalyzed trans-esterification process of JCO to reduce the viscosity and acidity. It is shown that basing on the streamer characteristics (shape, stopping length, velocity, current and electrical charge), JMEO could constitute a potential substitute for mineral for electrical insulation and especially in high voltage power transformers.

Comparison of streamers characteristics in jatropha curcas methyl ester oil and mineral oil under lightning impulse voltage

Due to their high biodegradability, non-toxicity and fire safety guarantee, vegetable-based oils are considered today as a potential substitute for mineral and synthetic liquids for electrical insulation and especially in high voltage power transformers. However, most of known vegetable oils are derived from food materials (rape-seeds, sunflower, soybeans, palms, corns and others). And one has to be vigilant to the fact that the replacement of mineral oil by natural ester fluids based on “renewably sourced” vegetable oils, does not create new problems as this could cause global food crisis due to diversion of food into insulating material oils or others (fuel). An interesting product can be jatropha curcas oil extracted from the fruits of jatropha curcas plants (“miracle tree”) which is non-food crops. These plants can be grown on marginal or degraded soils (thus avoiding the need to utilize those more fertile soils currently being used by smallholders to grow their staple crops); and it will readily grow in areas where annual rainfall levels are significantly lower than those required by other species such as rape-seeds, sunflower, palm, soybeans, corns and others. This paper presents an experimental study of streamers phenomena in jatropha curcas methyl ester oil (JMEO) and mineral oil (MO) under positive and negative lightning impulse voltages (1.2/50 μs). It is shown that basing on the shape and stopping length of streamers, JMEO could constitute a potential substitute for mineral and synthetic oils for electrical insulation and especially in high voltage power transformers.

Investigation of the influence of variations in the number and width of anti-notch depending on cogging torque reduction

Cogging torque is one of the electromagnetic torque. This torque appears at the beginning of the rotation of permanent magnet electric machine, caused by the interaction between the stator slots and an electromagnetic field generated by the permanent magnet. Cogging torque pursued as small as possible so that the movement of the rotor is not hampered. Cogging torque reduction have researched for many years with a lot of methods. This research study continued from earlier study of cogging torque reduction using anti notch method. In this paper, the width and variation in some anti notch became investigated variable to cut the cogging torque. The 4 degree half cylinder anti notch simulate using FEMM 4.2 and the result is 4 degree width and one of anti notch has the highest reduction of the cogging torque. Adding coupled number of anti notch is not too influence to cogging torque reduction.

Minimization of cogging torque based on different shape of anti-notch method

A Permanent Magnet Synchronous Generator (PMSG), part of a wind turbine, has a function to convert mechanical energy into electrical energy. To rotate the first cycle, the generator is blocked by an opponent torque called detent torque/unload torque or cogging torque. This study aim to reduce the cogging torque, modifying teeth formation on the surface of stator teeth. Simulation of the model used Finite Element Magnetic Method (FEMM) 4.2 software. From the simulation results of the reference and proposed models showed that half cylinder shape of the anti-notch (1st model) reduce cogging torque until 93.42% positive peak and 97.75% of negative peak from the reference model.

Jatropha curcas methyl ester oil obtaining as vegetable insulating oil

This paper presents a new vegetable oil that is jatropha curcas seeds oil as a substitute for mineral oil. This product has several advantages among which the fact that it is non-food crops and may be grown on low fertile soils and areas where annual rainfall levels are significantly lower than those required by other plants used to extract other vegetable oils such as rape-seeds, sunflower, corn, soybeans, grape-seeds and sesame. The considered natural ester oil is processed by alkali base catalyzed esterification process using potassium hydroxide (KOH) to produce jatropha curcas methyl ester oil (JMEO). The physicochemical (water content, relative density, viscosity, acidity, visual examination, color, iodine number, corrosivity, flash point, pour point) and electrical (breakdown voltage under ac, dc and impulse voltages) properties of JMEO are presented and discussed. A gas chromatography (GC) analysis is also achieved to identify the methyl ester components in JMEO. The breakdown voltage of JMEO is compared to that of mineral oil (MO). It is found that the average breakdown voltage of JMEO and MO under different voltage waveforms are too close.

Creeping discharges over pressboard immersed in jatropha curcas methyl ester and mineral oils

Due to their high biodegradability, non-toxicity and higher fire safety guarantee, vegetable-based oils are considered today as a potential substitute for mineral and synthetic liquids for electrical insulation and especially in high voltage power transformers. However most of known vegetable oils are derived from food materials (rape-seeds, sunflower, palm, olive). And one has to be vigilant to the fact that the replacement of mineral oil which is a petroleum-based product by natural ester fluids based on “renewably sourced” vegetable oils, does not create new problems as this could cause global food crisis due to diversion of food. An interesting product can be jatropha curcas oil extracted from jatropha curcas plants (“miracle tree”) which is non-food crops. This paper presents an experimental study of creeping discharges propagating over pressboard of different thicknesses immersed in jatropha curcas methyl ester oil (JMEO) and mineral oil (MO) under positive and negative lightning impulse voltages (1.2/50 μs), using two divergent electrode configurations (electrode point perpendicular and tangential to pressboard). It is shown that the thickness of pressboard significantly influences the characteristics of creeping discharge and especially the stopping (final) length Lf and the density of branches. For a given thickness, Lf increases with the voltage and decreases when the thickness increases. Lf is longer when the point is positive than with a negative point. For a given voltage and thickness of pressboard, the values of Lf in mineral oil and JMEO are very close.

Comparison of statistical breakdown voltages in jatropha curcas methyl ester oil and mineral oil under AC voltage

Due to their dielectric strength, viscosity and oxidation stability, mineral oils have been used for more than one hundred years ago as insulation liquid in high voltage equipment. However, mineral oils are non-renewable materials and have a low level biodegradability; their level of biodegradability is not more than 30 %. For that purpose, the development of vegetable oils is being continuously performed by many researchers and industries to replace mineral oils. These natural products present a high biodegradability, non-toxicity and higher fire safety guarantee. In general, vegetable oils which have been used today are derived from food material such as soybeans, palm, corn, sunflower and others. In this paper, we first introduce a new vegetable oil derived from a non-food material we called “JMEO (jatropha curcas methyl ester oil)”. JMEO is produced by alkaline esterification process of jatropha curcas oil which comes from the pressing of jatropha fruits. Jatropha curcas are non-edible crop that can grow in all types of soil in tropical and subtropical regions and even in barren soils with low rainfall. Moreover, these plants do not need much fertilizer. Then we present the results of a comparison of statistical AC breakdown voltage in JMEO and mineral oil (naphtenic type). Breakdown voltage (BDV) measurements have been performed on series of 40 tests basing on IEC 60156 Standard. Hypothesis test of conformity to normal distribution of BDV is carried out by applying Shapiro-Wilk tests to calculate W-value and P-value and skewness and kurtosis test. We mainly analyze histogram, probability of oil samples, mean and standard deviation. It appears from the obtained results that the BDV of JMEO is better than that of mineral oil. Thus, JMEO (jatropha curcas methyl ester oil) constitutes a potential liquid for replacing mineral oil in high voltage equipment and especially in high voltage power transformer.

Cogging torque reduction by modifying stator teeth and permanent magnet shape on a surface mounted PMSG

Cogging torque is an outstanding issue that regularly occurs in the Surface-mounted Permanent Magnet Synchronous Generator (SM-PMSG). Cogging torque is importand to be reduced because it will generate noise and friction on the generator so it will decrease the efficiency and lifetime of the generator. For wind turbine application, the cogging torque will hold back the production of electrical power. Many methods are developed to reduce the cogging torque. In this study, the authors proposes methods of reducing cogging torque by modifying stator teeth and the permanent magnet of the rotor. three proposed models and a reference model of generator were, simulated using FEMM 4.2 software. The reduction of cogging torque after correspondence with the reference model is modification stator teeth by adding Half-Cylinder anti-notch is 93,3%, a bread-loaf permanent magnet model is 39,1% and a combination model is 78,1% at positive peak.

Statistical analysis of AC and DC breakdown voltage of JMEO (Jatropha methyl ester oil), mineral oil and their mixtures

This paper reports on a comparative study of statistical Breakdown Voltage (BDV) in a natural ester oil namely jatropha curcas methyl ester oil (JMEO) extracted from the fruit seeds of jatropha curcas plants, mineral oil (MO) and two JMEO/MO oil mixtures (namely (50%JMEO+50%MO) and (80%JMEO+20%MO)) using spherical electrode under DC and AC voltages. It is shown that the average AC breakdown voltage of JMEO is higher than that of mineral oil. Meanwhile it is similar under DC voltage. The statistical analysis shows that all large data groups (n>40) for AC and DC breakdown voltages of JMEO, MO and oil mixtures obey to the normal distribution law. This is proved using Shapiro-Wilk test, skewness and kurtosis values. It also observed that AC mean breakdown voltage of JMEO is higher than that of oils mixture (50%JMEO+50%MO) and MO, but it is similar with oils mixture (80%JMEO+20%MO). AC mean breakdown voltage of MO is the lowest one. DC mean breakdown voltages of JMEO, MO and oil mixtures (50%JMEO+50%MO) are similar. In contrast, DC mean breakdown voltage of oils mixture (80%JMEO+20%MO) is the highest one.