Pub Date : 2019-06-01DOI: 10.1109/ICDL.2019.8796675
Víctor A. Primo, B. García, D. Pérez, J. Burgos
The interest in the development of new nanodielectric fluids suitable for electrotechnical applications has increased significantly in the last decade. several authors have reported experiences on fluids manufactured using different base fluids and nanoparticles. most of these studies are focused on the comparison of the thermal and dielectric properties of the nanofluids and the base liquids and most authors have found that the addition of nanoparticles can lead to an improvement of the properties of insulating liquids. the main objective of this paper is to study the enhancement of the ac breakdown voltage (ac bv) at 50 hz achieved when dispersing nanoparticles (np) in transformer oil. in particular, transformer natural ester was used while the nanoparticles used were fe3o4 dissolved in a hydrocarbon base and carboxilyc acid. in order to obtain a good dispersion of the nanoparticles an ultrasonic agitator was used. the impact of moisture in the dielectric strength of fluids prepared with different concentrations of np was evaluated and compared with that of the natural ester. the experimental results show a certain improvement of the dielectric strength of the nanodielectric fluid compared to that of the natural ester.
{"title":"Analysing the impact of Moisture on the AC Breakdown Voltage on Natural Ester Based Nanodielectric Fluids","authors":"Víctor A. Primo, B. García, D. Pérez, J. Burgos","doi":"10.1109/ICDL.2019.8796675","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796675","url":null,"abstract":"The interest in the development of new nanodielectric fluids suitable for electrotechnical applications has increased significantly in the last decade. several authors have reported experiences on fluids manufactured using different base fluids and nanoparticles. most of these studies are focused on the comparison of the thermal and dielectric properties of the nanofluids and the base liquids and most authors have found that the addition of nanoparticles can lead to an improvement of the properties of insulating liquids. the main objective of this paper is to study the enhancement of the ac breakdown voltage (ac bv) at 50 hz achieved when dispersing nanoparticles (np) in transformer oil. in particular, transformer natural ester was used while the nanoparticles used were fe3o4 dissolved in a hydrocarbon base and carboxilyc acid. in order to obtain a good dispersion of the nanoparticles an ultrasonic agitator was used. the impact of moisture in the dielectric strength of fluids prepared with different concentrations of np was evaluated and compared with that of the natural ester. the experimental results show a certain improvement of the dielectric strength of the nanodielectric fluid compared to that of the natural ester.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"71 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128528152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ICDL.2019.8796566
H. Suyono, Moch. Dhofir, R. Hasanah
The impurity because of water presence in a palm oil under an inhomogeneous electric field has been investigated in this paper. The inhomogeneous field condition has been produced during the experiment using an arrangement of needle-plate electrodes with three different sharpness angles, namely 0°, 45°, dan 60°. An AC high voltage has been taken as the testing voltage while the gap between the needle and the plate electrodes used was 5 mm. Two levels of impurity in the palm oil have been considered, which were 2000ppm and 4000ppm. The experiment results showed that in a new and uncontaminated palm oil it was found that the more pointed the needle electrode was, the smaller would be the leakage current level. It implied that less uniform the electric field intensity between the electrodes, the smaller would be the leakage current level. The experiment results also showed that the water content in the palm oil decreased the breakdown voltage level significantly, and the more pointed needle electrode caused a decrease in the level of breakdown voltage of palm oil with water contaminants. It has also been observed during the experiments that the water droplets in the electric field were broken apart into smaller water droplets.
{"title":"Influence of Water Contaminants on the Breakdown Voltage and Leakage Current of Palm Oil under Inhomogeneous Electric Field","authors":"H. Suyono, Moch. Dhofir, R. Hasanah","doi":"10.1109/ICDL.2019.8796566","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796566","url":null,"abstract":"The impurity because of water presence in a palm oil under an inhomogeneous electric field has been investigated in this paper. The inhomogeneous field condition has been produced during the experiment using an arrangement of needle-plate electrodes with three different sharpness angles, namely 0°, 45°, dan 60°. An AC high voltage has been taken as the testing voltage while the gap between the needle and the plate electrodes used was 5 mm. Two levels of impurity in the palm oil have been considered, which were 2000ppm and 4000ppm. The experiment results showed that in a new and uncontaminated palm oil it was found that the more pointed the needle electrode was, the smaller would be the leakage current level. It implied that less uniform the electric field intensity between the electrodes, the smaller would be the leakage current level. The experiment results also showed that the water content in the palm oil decreased the breakdown voltage level significantly, and the more pointed needle electrode caused a decrease in the level of breakdown voltage of palm oil with water contaminants. It has also been observed during the experiments that the water droplets in the electric field were broken apart into smaller water droplets.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127205116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ICDL.2019.8796582
Tao Zhao, Minglin Fan, Nijie Chao, Yunpeng Liu, Zhongyuan Zhang
The existence of cellulose particles in insulating oil is regarded as one of the major reasons for insulation failures in power transformers. Therefore, this research conducts experimental study and theoretical analysis of cellulose particle bridging mechanism in natural ester oil (FR3) under DC electric field. First, the spherically capped electrodes are used to test the natural ester oil (FR3) with cellulose particles in the experiment. The cellulose particles motion and the bridge-forming process in natural ester oil (FR3) are observed under the experiment of DC voltage. Then based on the experimental observation results, the numerical simulation model of cellulose particles in FR3 insulating oil under DC voltage is established, and the physical mechanism of cellulose particles at different bridge stages is simulated and analyzed. The results indicate that the presence of cellulose particles distorts the electric field distribution in the oil gap. Finally, based on the analysis and comparison of the dielectrophoretic force of cellulose particles at different positions in the electrode gap, the adsorption, aggregation and growth rule of the cellulose particles near the electrode are explained. The interval leakage current measured during the bridge-forming process shows that cellulose particles lead to interval conductance increases and the insulation performance decreases.
{"title":"The Analysis of Cellulose Particles Bridging in Natural Ester Oil under DC Voltage","authors":"Tao Zhao, Minglin Fan, Nijie Chao, Yunpeng Liu, Zhongyuan Zhang","doi":"10.1109/ICDL.2019.8796582","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796582","url":null,"abstract":"The existence of cellulose particles in insulating oil is regarded as one of the major reasons for insulation failures in power transformers. Therefore, this research conducts experimental study and theoretical analysis of cellulose particle bridging mechanism in natural ester oil (FR3) under DC electric field. First, the spherically capped electrodes are used to test the natural ester oil (FR3) with cellulose particles in the experiment. The cellulose particles motion and the bridge-forming process in natural ester oil (FR3) are observed under the experiment of DC voltage. Then based on the experimental observation results, the numerical simulation model of cellulose particles in FR3 insulating oil under DC voltage is established, and the physical mechanism of cellulose particles at different bridge stages is simulated and analyzed. The results indicate that the presence of cellulose particles distorts the electric field distribution in the oil gap. Finally, based on the analysis and comparison of the dielectrophoretic force of cellulose particles at different positions in the electrode gap, the adsorption, aggregation and growth rule of the cellulose particles near the electrode are explained. The interval leakage current measured during the bridge-forming process shows that cellulose particles lead to interval conductance increases and the insulation performance decreases.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131020664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ICDL.2019.8796730
Yizhuo Hu, M. Dong, Jiacheng Xie, Guanghao Xu, Xinyi Ma, M. Ren
The insulation performance of oil-paper insulation power equipment is seriously affected by moisture in oil and pressboard, but the current dielectric response diagnosis technologies are difficult to distinguish the effect of moisture and aging. In order to seek an effective moisture assessment method based on dielectric response technologies, the low frequency relaxation of oil-impregnated pressboard is tested and analyzed. Firstly, oil-impregnated pressboard samples of different moisture contents were prepared; then the frequency dielectric responses were tested, and the low frequency relaxation curves were obtained; finally, the effect of moisture on low frequency relaxation was discussed. The test results show that, the relaxation peak increases by moisture content, while the characteristic frequency of the peak remains the same. Besides, a new relaxation peak appeared at higher frequency range when moisture content is above 4%, which is considered to be caused by free water in oil-impregnated pressboard.
{"title":"Effect of Moisture on Low Frequency Relaxation of Oil-Paper Insulation","authors":"Yizhuo Hu, M. Dong, Jiacheng Xie, Guanghao Xu, Xinyi Ma, M. Ren","doi":"10.1109/ICDL.2019.8796730","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796730","url":null,"abstract":"The insulation performance of oil-paper insulation power equipment is seriously affected by moisture in oil and pressboard, but the current dielectric response diagnosis technologies are difficult to distinguish the effect of moisture and aging. In order to seek an effective moisture assessment method based on dielectric response technologies, the low frequency relaxation of oil-impregnated pressboard is tested and analyzed. Firstly, oil-impregnated pressboard samples of different moisture contents were prepared; then the frequency dielectric responses were tested, and the low frequency relaxation curves were obtained; finally, the effect of moisture on low frequency relaxation was discussed. The test results show that, the relaxation peak increases by moisture content, while the characteristic frequency of the peak remains the same. Besides, a new relaxation peak appeared at higher frequency range when moisture content is above 4%, which is considered to be caused by free water in oil-impregnated pressboard.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128832555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ICDL.2019.8796606
G. Bellis, L. Calcara, M. Pompili, M. S. Sarto
Over the past years, there has been an increasing interest in natural ester insulating liquids for application in power transformers, thanks to their higher environmental compatibility and lower fire point, as compared to conventional mineral oils. The main function of a transformer oil is its ability to dissipate heat, while ensuring electrical insulation. Among the various influencing parameters, it is well known that heat exchange in a liquid is also affected by its viscosity. Thus, the temperature dependence of the viscosity of an insulating oil should be carefully considered in the design of the cooling system of a power transformer. In this study the variation of the dynamic viscosity with temperature of commercially available natural esters and mineral oils is compared. Steady state rheological measurements are carried out, through a controlled shear rate rotational rheometer, in the 20°C ÷ 100° temperature range, under isothermal conditions. Temperature ramps are also performed, while fixing the shear rate, with the aim of investigating the variation of the steady shear dynamic viscosity over the whole temperature range. Results demonstrate that the viscosity of natural esters, though being higher at low temperatures, compared to mineral oils, strongly decreases for higher temperatures, thus favouring heat transfer and reducing the risk of hot-spots, which might lead to insulation-failures.
{"title":"Temperature dependence of the shear viscosity of mineral oils and natural esters","authors":"G. Bellis, L. Calcara, M. Pompili, M. S. Sarto","doi":"10.1109/ICDL.2019.8796606","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796606","url":null,"abstract":"Over the past years, there has been an increasing interest in natural ester insulating liquids for application in power transformers, thanks to their higher environmental compatibility and lower fire point, as compared to conventional mineral oils. The main function of a transformer oil is its ability to dissipate heat, while ensuring electrical insulation. Among the various influencing parameters, it is well known that heat exchange in a liquid is also affected by its viscosity. Thus, the temperature dependence of the viscosity of an insulating oil should be carefully considered in the design of the cooling system of a power transformer. In this study the variation of the dynamic viscosity with temperature of commercially available natural esters and mineral oils is compared. Steady state rheological measurements are carried out, through a controlled shear rate rotational rheometer, in the 20°C ÷ 100° temperature range, under isothermal conditions. Temperature ramps are also performed, while fixing the shear rate, with the aim of investigating the variation of the steady shear dynamic viscosity over the whole temperature range. Results demonstrate that the viscosity of natural esters, though being higher at low temperatures, compared to mineral oils, strongly decreases for higher temperatures, thus favouring heat transfer and reducing the risk of hot-spots, which might lead to insulation-failures.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121126946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ICDL.2019.8796642
T. Nganpitak, P. Nimsanong, S. Maneerot, N. Pattanadech
Polarization and Depolarization current (PDC) method is one of non-destructive insulation testing methods that can be used for diagnosis the insulation conditions of high voltage equipment. This paper presents the PDC analysis of an oil immersed distribution transformer measured during the manufacturing process. A 22 kV, 30 kVA single phase transformer was designed and constructed. During manufacturing process, the polarization current and depolarization current of the transformer insulation were measured for 6 case studies as follows: 1) paper insulation between iron core and low voltage (LV) windings before dry and vacuum in the oven, 2) paper insulation between LV and high voltage (HV) windings before dry and vacuum in the oven, 3) paper insulation between iron core and LV windings after dry and vacuum in the oven, 4) paper insulation between LV and HV windings after dry and vacuum in the oven, 5) oilpaper insulation between iron core and LV windings after dry and impregnation process and 6) oil-paper insulation between LV and HV windings after dry and impregnation process. Then, PDC test results were analyzed. It was found that the moisture content in the paper insulation clearly affected the capacitance at power frequency, and PDC shapes. Besides, the impregnation process had a good effect on the capacitance ratio and dielectric dissipation factor. Moreover, the current difference of dry paper insulation between HV and LV windings presented the nonlinear characteristic both before and after impregnation process.
{"title":"Dielectric Response Analysis of Mineral Oil Immersed Transformer Insulation during Manufacturing Process","authors":"T. Nganpitak, P. Nimsanong, S. Maneerot, N. Pattanadech","doi":"10.1109/ICDL.2019.8796642","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796642","url":null,"abstract":"Polarization and Depolarization current (PDC) method is one of non-destructive insulation testing methods that can be used for diagnosis the insulation conditions of high voltage equipment. This paper presents the PDC analysis of an oil immersed distribution transformer measured during the manufacturing process. A 22 kV, 30 kVA single phase transformer was designed and constructed. During manufacturing process, the polarization current and depolarization current of the transformer insulation were measured for 6 case studies as follows: 1) paper insulation between iron core and low voltage (LV) windings before dry and vacuum in the oven, 2) paper insulation between LV and high voltage (HV) windings before dry and vacuum in the oven, 3) paper insulation between iron core and LV windings after dry and vacuum in the oven, 4) paper insulation between LV and HV windings after dry and vacuum in the oven, 5) oilpaper insulation between iron core and LV windings after dry and impregnation process and 6) oil-paper insulation between LV and HV windings after dry and impregnation process. Then, PDC test results were analyzed. It was found that the moisture content in the paper insulation clearly affected the capacitance at power frequency, and PDC shapes. Besides, the impregnation process had a good effect on the capacitance ratio and dielectric dissipation factor. Moreover, the current difference of dry paper insulation between HV and LV windings presented the nonlinear characteristic both before and after impregnation process.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121045984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vegetable insulating oils, as promising substitutes for mineral insulating oils, have gained a lot of researches on their modification. Polyhedral Oligomeric Silsesquioxanes (POSS), a hybrid organic-inorganic nanoparticle, is of great prospect in vegetable insulating oil modification based on its remarkable dispersion property in organic liquids. In this research, the test material of vegetable oil (FR3, to be specified) was mixed with OctaMethyl-POSS (OM-POSS) in several different concentrations 0, 0.001, 0.004, 0.007 and 0.01 wt.% to make modified dielectric nanofluids. The AC breakdown strength and dielectric properties (relative permittivity, electrical conductivity and dissipation factor) of POSS-based oils were investigated. The experimental results showed that the AC breakdown strength of POSS-based nanofluids increased in a proper concentration range, while the permittivity, conductivity and dissipation factor of tested samples exhibited a reduction with proper POSS concentrations, where the model of interfacial zone was applied to explain the mechanism.
{"title":"The Application of Polyhedral Oligomeric Silsesquioxanes on Vegetable Insulating Oil Modification","authors":"Qiuhuang Han, Feipeng Wang, Jian Li, Kaizheng Wang, Qi Zhao, Kelin Hu","doi":"10.1109/ICDL.2019.8796708","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796708","url":null,"abstract":"Vegetable insulating oils, as promising substitutes for mineral insulating oils, have gained a lot of researches on their modification. Polyhedral Oligomeric Silsesquioxanes (POSS), a hybrid organic-inorganic nanoparticle, is of great prospect in vegetable insulating oil modification based on its remarkable dispersion property in organic liquids. In this research, the test material of vegetable oil (FR3, to be specified) was mixed with OctaMethyl-POSS (OM-POSS) in several different concentrations 0, 0.001, 0.004, 0.007 and 0.01 wt.% to make modified dielectric nanofluids. The AC breakdown strength and dielectric properties (relative permittivity, electrical conductivity and dissipation factor) of POSS-based oils were investigated. The experimental results showed that the AC breakdown strength of POSS-based nanofluids increased in a proper concentration range, while the permittivity, conductivity and dissipation factor of tested samples exhibited a reduction with proper POSS concentrations, where the model of interfacial zone was applied to explain the mechanism.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125105996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Resin impregnated paper (RIP) wall bushing is the only channel connecting the valve hall to the outdoor DC field. It carries full voltage, full current and strong mechanical stress in long-term operation. Long-term thermal expansion and contraction causes the electrical contact wear of the outdoor part to be very serious, and it is prone to overheating failure. The local overheating will accelerating the fretting wear and corrosion, which will decrease the insulation and mechanical performance of RIP core. The byproduct also may fall out and distort the electrical field. Therefore, it is vital to maintain the overheating faulted bushing in time. In this paper, firstly the 3-dimentional finite element model of ±500kV DC wall bushing including connect structure was established. Then the thermal field distribution of wall bushing with the contact fingers with different degrees of deterioration were simulated. The correspondence between the temperature of the fault point and the temperature of the sheath were established. Finally, the correspondence were successfully applied to maintain a faulted wall bushing before destructive overheating fault occurs. This research can provide a basis for monitoring the overheating fault of the bushing with an infrared camera.
{"title":"Research on the Overheating Fault of HVDC Wall Bushing and its Dignosis Strategies Based on CFD","authors":"H. Tian, Shiyi Zhou, Xinyi Ma, Chuanyang Li, Jianwei Chen, Zongren Peng","doi":"10.1109/ICDL.2019.8796545","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796545","url":null,"abstract":"Resin impregnated paper (RIP) wall bushing is the only channel connecting the valve hall to the outdoor DC field. It carries full voltage, full current and strong mechanical stress in long-term operation. Long-term thermal expansion and contraction causes the electrical contact wear of the outdoor part to be very serious, and it is prone to overheating failure. The local overheating will accelerating the fretting wear and corrosion, which will decrease the insulation and mechanical performance of RIP core. The byproduct also may fall out and distort the electrical field. Therefore, it is vital to maintain the overheating faulted bushing in time. In this paper, firstly the 3-dimentional finite element model of ±500kV DC wall bushing including connect structure was established. Then the thermal field distribution of wall bushing with the contact fingers with different degrees of deterioration were simulated. The correspondence between the temperature of the fault point and the temperature of the sheath were established. Finally, the correspondence were successfully applied to maintain a faulted wall bushing before destructive overheating fault occurs. This research can provide a basis for monitoring the overheating fault of the bushing with an infrared camera.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131551240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Partial Discharge (PD) diagnostic become more important for high voltage (HV) equipment condition monitoring. PD phenomenon in power transformer could indicate insulation aging or degradation, which in long term could reduce the integrity of the insulation and leading to transformer failure. High accuracy of recognition rate for different PD defect is necessary for a successful PD diagnostic. This paper presents Random Forest (RF) method for PD defect recognition in power transformer. RF is one of supervised learning algorithm in machine learning. RF known as an ensemble classifier build using many decision trees. The majority vote of each three will determine the PD type. There are three defects used in this paper, protrusion, floating metal, and void. A commercial PD measurement system and detecting impedance was used to record the phase resolved partial discharge (PRPD) patterns of different defects. 8 PD statistical features extracted from PRPD patterns to identify each defect. To calculate the accuracy of RF method, different amount of PD features was use for recognition and then compare with other methods.
{"title":"Partial Discharge Defect Recognition in Power Transformer using Random Forest","authors":"Ismail Hartanto Kartojo, Yan-Bo Wang, Guanjun Zhang, Suwarno","doi":"10.1109/ICDL.2019.8796809","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796809","url":null,"abstract":"Partial Discharge (PD) diagnostic become more important for high voltage (HV) equipment condition monitoring. PD phenomenon in power transformer could indicate insulation aging or degradation, which in long term could reduce the integrity of the insulation and leading to transformer failure. High accuracy of recognition rate for different PD defect is necessary for a successful PD diagnostic. This paper presents Random Forest (RF) method for PD defect recognition in power transformer. RF is one of supervised learning algorithm in machine learning. RF known as an ensemble classifier build using many decision trees. The majority vote of each three will determine the PD type. There are three defects used in this paper, protrusion, floating metal, and void. A commercial PD measurement system and detecting impedance was used to record the phase resolved partial discharge (PRPD) patterns of different defects. 8 PD statistical features extracted from PRPD patterns to identify each defect. To calculate the accuracy of RF method, different amount of PD features was use for recognition and then compare with other methods.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133769340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ICDL.2019.8796546
Xiang Zhang, Zhongdong Wang, Qiang Liu, A. Gyore, K. Rapp
Retrofilling transformers with a new liquid has been considered as an option for life extension and/or uprating purposes. The determination of the new total liquid flow rate is of vital importance in assessing the effect of retrofilling on flow and temperature distributions in the winding, especially for ON transformers. This paper presents the determination of flow rate ratios for four liquids—a mineral oil, a GTL oil, a synthetic ester and a natural ester—in ON transformer retrofilling scenarios. Flow rate ratios among different liquids are provided for a simplified condition of linear radiator oil temperature variation. For a more realistic exponential radiator oil temperature variation, the detailed transformer geometric information is needed to estimate the total flow rate. In addition, a hydraulic winding network model is established to prove that “minor pressure losses” due to change of flow directions is indeed minor for ON transformer liquid flow conditions, justifying neglecting the minor losses in the deduction of the total liquid flow rate.
{"title":"Investigation of the Total Flow Rates in Oil Natural Transformer Retrofilling Scenarios","authors":"Xiang Zhang, Zhongdong Wang, Qiang Liu, A. Gyore, K. Rapp","doi":"10.1109/ICDL.2019.8796546","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796546","url":null,"abstract":"Retrofilling transformers with a new liquid has been considered as an option for life extension and/or uprating purposes. The determination of the new total liquid flow rate is of vital importance in assessing the effect of retrofilling on flow and temperature distributions in the winding, especially for ON transformers. This paper presents the determination of flow rate ratios for four liquids—a mineral oil, a GTL oil, a synthetic ester and a natural ester—in ON transformer retrofilling scenarios. Flow rate ratios among different liquids are provided for a simplified condition of linear radiator oil temperature variation. For a more realistic exponential radiator oil temperature variation, the detailed transformer geometric information is needed to estimate the total flow rate. In addition, a hydraulic winding network model is established to prove that “minor pressure losses” due to change of flow directions is indeed minor for ON transformer liquid flow conditions, justifying neglecting the minor losses in the deduction of the total liquid flow rate.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115312480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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