Articles
<![CDATA[Leakage Current Waveforms and Arcing Characteristics of Epoxy Resin for Outdoor Insulators under Clean and Salt Fogs ]]>
<![CDATA[Suwarno, Suwarno]]>;
<![CDATA[Ardianto, S. K.]]>
<![CDATA[ Journal of Engineering and Technological Sciences Vol 40, No 1 (2008) ]]>
Publisher : <![CDATA[ITB Journal Publisher, LPPM ITB ]]>
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DOI: 10.5614/itbj.eng.sci.2008.40.1.3
<![CDATA[Ceramic outdoor insulators have been used in high voltage transmission lines since long time ago. Due to superiority in their resistance to pollution, recently, polymeric outdoor insulators are widely used. Epoxy resin is one polymer which shows good properties for outdoor insulation. During service, outdoor insulators may severe a certain degree of pollution which may reduce their surface resistance. Leakage current (LC) usually  increase and degradation may take place. This paper reports experimental results on the leakage current waveforms and arcing characteristics of epoxy resin under clean and salt fog. The samples used are blocks of epoxy resin with dimension of 250 x 50 x 20 mm3 . The samples were put in a test chamber with dimension of 900x900x1200 mm3 with controllable humidity and pollution conditions. Clean and salt fog were generated according to IEC 60-1 and 507. The arcing experiment was  done with incline plane test in accordance with IEC 587. AC voltage in the range from 5 kV to 50 kV with frequency of 50 Hz was applied. The LC waveforms up to flash over were measured. The magnitudes as well as harmonic content of the LC were analyzed.  The correlation between LC waveforms and dry band arching phenomenon was elaborated. Visual observation of the arc on the sample surfaces was observed using a video camera. Experimental results indicated that LC magnitude on clean samples was slightly affected by humidity (RH). However, under salt fog, RH greatly affected the LC magnitude. The flashover voltage of clean samples under salt fog reduced significantly for fog conductivity of more than  1.2 mS/cm. Kaolin-polluted samples under salt fog showed an Ohmic behaviour. The LC magnitude was high and a large discrepancy of LC magnitude was observed for high applied voltage of larger than 25 kV. The largest LC magnitude was observed on salt-kaolin polluted samples under clean fog at high RH. LC waveforms analysis indicated that in general LC waveforms were distorted from sinusoidal. For clean samples under clean fog, THD of LC decreased with RH but slightly increased with the applied voltage. Large distortion at the peak of LC waveform was observed on kaolin polluted sample under salt fog of 3.6 mS/cm and high RH and high applied voltage. This correlates with corona arc on the sample surface. Similar behaviour was observed on kaolin-salt polluted samples under clean fog. Tracking arc experiment indicated that arc length LC magnitude and arc intensity increased with the pollutant conductivity. The THD also significantly increased with pollutant conductivity. At conductivity of less than 0.6 mS/cm the unsymmetrical LC waveforms were obtained. However, symmetrical LC waveforms were observed for conductivity of 0.9 and 1.2 mS/cm. The change of LC magnitude and waveform at different condition of samples may be useful for the diagnostics of insulator condition.]]>
<![CDATA[Comparison of Eight Month Coastal Polluted Porcelain and Epoxy Resin Outdoor Insulators ]]>
<![CDATA[Waluyo, Waluyo]]>;
<![CDATA[Sinisuka, Ngapuli I.]]>;
<![CDATA[Pakpahan, Parouli M.]]>;
<![CDATA[Suwarno, Suwarno]]>;
<![CDATA[Djauhari, Maman A.]]>
<![CDATA[ Journal of Engineering and Technological Sciences Vol 40, No 2 (2008) ]]>
Publisher : <![CDATA[ITB Journal Publisher, LPPM ITB ]]>
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DOI: 10.5614/itbj.eng.sci.2008.40.2.4
<![CDATA[This study presents the experimental results of eight months naturally coastal polluted outdoor porcelain and epoxy resin insulators. The experiments were leakage current and applied high voltage measurements used a two-channel storage digital oscilloscope, in the hermetically sealed chamber, where temperature, humidity , pressure and applied voltage could be adjusted and measured simultaneously. The leakage current waveforms were analyzed using FFT and the relation to environmental parameters were analyzed using correlation matrix of multivariate statistical tools. It was also conducted SEM and EDAX tests. Base on the correlation coefficient matrix, the humidity contributed to leakage current amplitude and phase angle on the porcelain insulator  were very significant, with the correlation coefficient were 0.60 and -0.68 respectively. Whereas, on polluted epoxy resin insulator, the humidity did not influence to leakage current and phase angle considerably. Generally, the surface became rougher than the new one. The most three chemical elements in pollutants were chlorine, silicon and ferrum.]]>
<![CDATA[A Comparison of Dielectric Properties of Palm Oil with Mineral and Synthetic Types Insulating Liquid under Temperature Variation ]]>
<![CDATA[Rajab, Abdul]]>;
<![CDATA[Sulaeman, Aminuddin]]>;
<![CDATA[Sudirham, Sudaryatno]]>;
<![CDATA[Suwarno, Suwarno]]>
<![CDATA[ Journal of Engineering and Technological Sciences Vol 43, No 3 (2011) ]]>
Publisher : <![CDATA[ITB Journal Publisher, LPPM ITB ]]>
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DOI: 10.5614/itbj.eng.sci.2011.43.3.3
<![CDATA[Mineral oil is known to have a low biodegradability level and high susceptibility to the fire. These conditions motivate many researchers to look for alternative sources for insulating oil. One of the alternative liquid is palm oil. To verify the suitability of using palm oil as an insulating liquid, it is important to make dielectric properties comparison with the commonly used insulating liquid. This paper presents comparison of temperature effect on dielectric properties of palm oil with mineral type insulating liquid and silicone oil. The measured parameters were breakdown voltage, dissipation factor (tan δ), and dielectric constant. Breakdown voltage measurement was performed in accordance with IEC 156 standard, whereas, the dissipation factor and dielectric constant measurement were conducted based on IEC 60247 standard test methods. The results showed that variations of dielectric properties of palm oil to the temperature change, in general, have the same tendency with those of commonly used insulating liquids i.e. mineral oil and silicone oil. Breakdown voltages and dissipation factors of all tested oils were increased, while their dielectric constants were slightly decreased with the increase of temperature.]]>
<![CDATA[Partial Discharge Phase Distribution of Palm Oil as Insulating Liquid ]]>
<![CDATA[Abdul Rajab]]>;
<![CDATA[Umar K. Umar K.]]>;
<![CDATA[D. Hamdani D. Hamdani]]>;
<![CDATA[Aminuddin S. Aminuddin S.]]>;
<![CDATA[Suwarno Suwarno]]>;
<![CDATA[Y. Abe Y. Abe]]>;
<![CDATA[M. Tsuchie M. Tsuchie]]>;
<![CDATA[M. Kozako M. Kozako]]>;
<![CDATA[S. Ohtsuka S. Ohtsuka]]>;
<![CDATA[M. Hikita M. Hikita]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v9i1.683
<![CDATA[Due to the low biodegradability level of mineral oil and its susceptibility to the fire, palm oil was proposed as alternative insulating liquid. This paper discusses partial discharge (PD) in palm oil under sinusoidal voltages and the comparison with mineral oil. PD was generated using a needle-plane electrode configuration which is enable enhancing electric field at the needle tip. PD pulses were detected using RC detector and they were measured using a Computer-based partial discharge measurement system. The results showed that PD activities in both oils are similar. The PD was initiated at the negative polarity of applied voltage. The discharges took place in both polarity’s of applied voltage with PD number was higher at negative one. Several discharges phenomena showed the presence of space charge which changed electric field and governed PD activities besides the main field introduced by voltage application.]]>
<![CDATA[Simulation of Partial Discharge Induced Electromagnetic Wave in Power Transformer ]]>
<![CDATA[Nhet Ra]]>;
<![CDATA[Tomohiro Kawashima]]>;
<![CDATA[Naohiro Hozumi]]>;
<![CDATA[Yoshinobu Murakami]]>;
<![CDATA[Umar Khayam]]>;
<![CDATA[Suwarno Suwarno]]>
<![CDATA[ EPI International Journal of Engineering Vol 1 No 1 (2018): Volume 1 Number 1, February 2018 ]]>
Publisher : <![CDATA[Center of Techonolgy (COT), Engineering Faculty, Hasanuddin University ]]>
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<![CDATA[This paper describes the numerical simulation of partial discharge (PD) in oil-filled power transformer using FDTD method (Finite Difference Time Domain). We investigated the effects of oil insulation medium and internal structures on the propagation of electromagnetic signal emitted from the partial discharge source. In this study, partial discharge was modeled as the Gaussian Pulse with the width 20ns. To observe the electromagnetic intensity and also the voltage distribution, three sensors were employed. The magnitude, frequency, and attenuation of the EM wave without internal structure and with internal structure were compared. The Results show that the EM wave intensity attenuated while propagating through the winding and oil insulation. And the time arrival of each signal is different due to its distance from the PD source. The first dominance frequency of the simulation without and with winding and core occur in 1 GHz of frequency. However, the frequency spectrum of simulation with winding and core has a resonance frequency in the low region which is 80 MHz of frequency. This is explained as the winding is considered as a loop antenna]]>
<![CDATA[Leakage Current Waveforms and Arcing Characteristics of Epoxy Resin for Outdoor Insulators under Clean and Salt Fogs ]]>
<![CDATA[Suwarno Suwarno]]>;
<![CDATA[S. K. Ardianto]]>
<![CDATA[ Journal of Engineering and Technological Sciences Vol. 40 No. 1 (2008) ]]>
Publisher : <![CDATA[Institute for Research and Community Services, Institut Teknologi Bandung ]]>
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DOI: 10.5614/itbj.eng.sci.2008.40.1.3
<![CDATA[Ceramic outdoor insulators have been used in high voltage transmission lines since long time ago. Due to superiority in their resistance to pollution, recently, polymeric outdoor insulators are widely used. Epoxy resin is one polymer which shows good properties for outdoor insulation. During service, outdoor insulators may severe a certain degree of pollution which may reduce their surface resistance. Leakage current (LC) usually increase and degradation may take place. This paper reports experimental results on the leakage current waveforms and arcing characteristics of epoxy resin under clean and salt fog. The samples used are blocks of epoxy resin with dimension of 250 x 50 x 20 mm3 . The samples were put in a test chamber with dimension of 900x900x1200 mm3 with controllable humidity and pollution conditions. Clean and salt fog were generated according to IEC 60-1 and 507. The arcing experiment was done with incline plane test in accordance with IEC 587. AC voltage in the range from 5 kV to 50 kV with frequency of 50 Hz was applied. The LC waveforms up to flash over were measured. The magnitudes as well as harmonic content of the LC were analyzed. The correlation between LC waveforms and dry band arching phenomenon was elaborated. Visual observation of the arc on the sample surfaces was observed using a video camera. Experimental results indicated that LC magnitude on clean samples was slightly affected by humidity (RH). However, under salt fog, RH greatly affected the LC magnitude. The flashover voltage of clean samples under salt fog reduced significantly for fog conductivity of more than 1.2 mS/cm. Kaolin-polluted samples under salt fog showed an Ohmic behaviour. The LC magnitude was high and a large discrepancy of LC magnitude was observed for high applied voltage of larger than 25 kV. The largest LC magnitude was observed on salt-kaolin polluted samples under clean fog at high RH. LC waveforms analysis indicated that in general LC waveforms were distorted from sinusoidal. For clean samples under clean fog, THD of LC decreased with RH but slightly increased with the applied voltage. Large distortion at the peak of LC waveform was observed on kaolin polluted sample under salt fog of 3.6 mS/cm and high RH and high applied voltage. This correlates with corona arc on the sample surface. Similar behaviour was observed on kaolin-salt polluted samples under clean fog. Tracking arc experiment indicated that arc length LC magnitude and arc intensity increased with the pollutant conductivity. The THD also significantly increased with pollutant conductivity. At conductivity of less than 0.6 mS/cm the unsymmetrical LC waveforms were obtained. However, symmetrical LC waveforms were observed for conductivity of 0.9 and 1.2 mS/cm. The change of LC magnitude and waveform at different condition of samples may be useful for the diagnostics of insulator condition.]]>
<![CDATA[Comparison of Eight Month Coastal Polluted Porcelain and Epoxy Resin Outdoor Insulators ]]>
<![CDATA[Waluyo Waluyo]]>;
<![CDATA[Ngapuli I. Sinisuka]]>;
<![CDATA[Parouli M. Pakpahan]]>;
<![CDATA[Suwarno Suwarno]]>;
<![CDATA[Maman A. Djauhari]]>
<![CDATA[ Journal of Engineering and Technological Sciences Vol. 40 No. 2 (2008) ]]>
Publisher : <![CDATA[Institute for Research and Community Services, Institut Teknologi Bandung ]]>
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DOI: 10.5614/itbj.eng.sci.2008.40.2.4
<![CDATA[This study presents the experimental results of eight months naturally coastal polluted outdoor porcelain and epoxy resin insulators. The experiments were leakage current and applied high voltage measurements used a two-channel storage digital oscilloscope, in the hermetically sealed chamber, where temperature, humidity , pressure and applied voltage could be adjusted and measured simultaneously. The leakage current waveforms were analyzed using FFT and the relation to environmental parameters were analyzed using correlation matrix of multivariate statistical tools. It was also conducted SEM and EDAX tests. Base on the correlation coefficient matrix, the humidity contributed to leakage current amplitude and phase angle on the porcelain insulator were very significant, with the correlation coefficient were 0.60 and -0.68 respectively. Whereas, on polluted epoxy resin insulator, the humidity did not influence to leakage current and phase angle considerably. Generally, the surface became rougher than the new one. The most three chemical elements in pollutants were chlorine, silicon and ferrum.]]>
<![CDATA[A Comparison of Dielectric Properties of Palm Oil with Mineral and Synthetic Types Insulating Liquid under Temperature Variation ]]>
<![CDATA[Abdul Rajab]]>;
<![CDATA[Aminuddin Sulaeman]]>;
<![CDATA[Sudaryatno Sudirham]]>;
<![CDATA[Suwarno Suwarno]]>
<![CDATA[ Journal of Engineering and Technological Sciences Vol. 43 No. 3 (2011) ]]>
Publisher : <![CDATA[Institute for Research and Community Services, Institut Teknologi Bandung ]]>
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DOI: 10.5614/itbj.eng.sci.2011.43.3.3
<![CDATA[Mineral oil is known to have a low biodegradability level and high susceptibility to the fire. These conditions motivate many researchers to look for alternative sources for insulating oil. One of the alternative liquid is palm oil. To verify the suitability of using palm oil as an insulating liquid, it is important to make dielectric properties comparison with the commonly used insulating liquid. This paper presents comparison of temperature effect on dielectric properties of palm oil with mineral type insulating liquid and silicone oil. The measured parameters were breakdown voltage, dissipation factor (tan δ), and dielectric constant. Breakdown voltage measurement was performed in accordance with IEC 156 standard, whereas, the dissipation factor and dielectric constant measurement were conducted based on IEC 60247 standard test methods. The results showed that variations of dielectric properties of palm oil to the temperature change, in general, have the same tendency with those of commonly used insulating liquids i.e. mineral oil and silicone oil. Breakdown voltages and dissipation factors of all tested oils were increased, while their dielectric constants were slightly decreased with the increase of temperature.]]>
<![CDATA[The Effect of Coating on Leakage Current Characteristic of Coast Field Aged Ceramic Insulator ]]>
<![CDATA[Dini Fauziah]]>;
<![CDATA[Heldi Alfiadi]]>;
<![CDATA[Rachmawati Rachmawati]]>;
<![CDATA[Suwarno Suwarno]]>
<![CDATA[ Proceeding of the Electrical Engineering Computer Science and Informatics Vol 4: EECSI 2017 ]]>
Publisher : <![CDATA[IAES Indonesia Section ]]>
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DOI: 10.11591/eecsi.v4.1028
<![CDATA[Ceramic insulator is widely used in Indonesian electrical power distribution system. Based on previous research, it is obtained that silicone rubber coating can improve the performance of ceramic insulator due to better hydrophobicity. This paper presents performance of ceramic insulator with and without silicone rubber coating in a coastal area of Pangandaran. 6 silicone rubber coated and 6 uncoated of 20 kV distribution insulators have been installed in the field to get natural aging process for 5 years and 4 months. Along the aging process, their surface properties have been checked periodically. Monitored parameters are magnitude of leakage current, THD, hydrophobicity, and surface temperature of insulator. The result has shown that after 5 years and 4 months aging in coastal area without maintenance, silicone rubber coated ceramic insulator has better performance.]]>
<![CDATA[Simulasi Pemohonan Listrik (Electrical Treeing) pada Isolasi Polimer dengan Menggunakan Metode Cellular Automata ]]>
<![CDATA[Suwarno Suwarno]]>;
<![CDATA[Ronald P. Hutahean]]>
<![CDATA[ Journal of Mathematical and Fundamental Sciences Vol. 37 No. 2 (2005) ]]>
Publisher : <![CDATA[Institute for Research and Community Services (LPPM) ITB ]]>
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DOI: 10.5614/itbj.sci.2005.37.2.3
<![CDATA[Recently, polymeric insulating materials are widely used for high voltage cables. During operation, a field enhancement sites such as void and protrusion may exist in the polymeric insulation. Degradation of the insulation may occur and the so-called electrical treeing will grow. The electrical treeing appears in the polymeric insulation in the form of tree-like structure with very fine cylindrical channels similar to the trunks and branches in an actual tree. The appearance of an electrical treeing is a sign that a harmful degradation is developing in the insulation. In order to avoid the electrical treeing to occur in the polymeric insulation and for diagnosing of the condition, it is important to know the behavior of the electrical treeing and the correlation with the insulation materials. This paper reports a computer simulation results of the behavior of the electrical treeing using Cellular Automata. The simulation was done in polymeric materials with various critical electric fields. The simulation results showed that selection of polymeric insulating materials with high critical field is a very important step in the design of insulation.]]>
