Pub Date : 2016-08-23DOI: 10.1109/ICD.2016.7547719
I. Iddrissu, Z. Lv, S. Rowland
Simultaneous imaging of electrical tree growth and partial discharge measurement have allowed 5 stages of tree growth to be identified. Partial discharge (PD) characteristics have been collected from tree growth in needle-plane epoxy resin samples under 15 kV peak AC voltage, and have been shown to behave differently at different stages of tree growth. Initial slow growth is accompanied by large discharges (about 10 pC). Thereafter, growth of fine channels is associated with smaller PDs (about 0.3 pC). It was observed that the tree propagation is further driven by even smaller PDs below the equipment sensitivity. However, when the tree approaches the counter electrode, the PD magnitude increases again and a more substantial tree grows with a low propagation rate. Reverse tree channels then occur from the planar electrode towards the needle, together with higher magnitude PDs characterized by thick and dark branches before breakdown.
{"title":"The dynamic character of partial discharge in epoxy resin at different stages of treeing","authors":"I. Iddrissu, Z. Lv, S. Rowland","doi":"10.1109/ICD.2016.7547719","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547719","url":null,"abstract":"Simultaneous imaging of electrical tree growth and partial discharge measurement have allowed 5 stages of tree growth to be identified. Partial discharge (PD) characteristics have been collected from tree growth in needle-plane epoxy resin samples under 15 kV peak AC voltage, and have been shown to behave differently at different stages of tree growth. Initial slow growth is accompanied by large discharges (about 10 pC). Thereafter, growth of fine channels is associated with smaller PDs (about 0.3 pC). It was observed that the tree propagation is further driven by even smaller PDs below the equipment sensitivity. However, when the tree approaches the counter electrode, the PD magnitude increases again and a more substantial tree grows with a low propagation rate. Reverse tree channels then occur from the planar electrode towards the needle, together with higher magnitude PDs characterized by thick and dark branches before breakdown.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127796407","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 : 2016-08-23DOI: 10.1109/ICD.2016.7547559
Jia Meng, Penghao Zhang, Yewen Zhang, F. Zheng, H Zhao, Z. An
Recently, based on our successful exhibition of charge packets phenomenon under a series of electric field intensity (ranges from 10 kV/mm to 50 kV/mm) in LLDPE thin films (500 μm), the retrival of real charge carrier mobility was attempted to work out using numerical methods. To make the migration of charge packets in both numerical simulations and experimental measurements incline to unanimous, a slightly adjusted bipolar charge transport model was adopted for charge packet simulations and a preset electric field-charge migration speed carve was tuned during the iterative simulations. Results show that simulation using this model is qualified for the charge packet reproduction. The simulated charge distribution is more precise than that in former research, and verification simulations basing on the final retrieved carrier mobility carve suit well with the measurement results.
{"title":"Improvement of precise retrival for charge mobility from charge packet measurements in LLDPE films","authors":"Jia Meng, Penghao Zhang, Yewen Zhang, F. Zheng, H Zhao, Z. An","doi":"10.1109/ICD.2016.7547559","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547559","url":null,"abstract":"Recently, based on our successful exhibition of charge packets phenomenon under a series of electric field intensity (ranges from 10 kV/mm to 50 kV/mm) in LLDPE thin films (500 μm), the retrival of real charge carrier mobility was attempted to work out using numerical methods. To make the migration of charge packets in both numerical simulations and experimental measurements incline to unanimous, a slightly adjusted bipolar charge transport model was adopted for charge packet simulations and a preset electric field-charge migration speed carve was tuned during the iterative simulations. Results show that simulation using this model is qualified for the charge packet reproduction. The simulated charge distribution is more precise than that in former research, and verification simulations basing on the final retrieved carrier mobility carve suit well with the measurement results.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131080911","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 : 2016-08-23DOI: 10.1109/ICD.2016.7547657
H. V. Nguyen, B. Phung, T. Blackburn
As the use VLF diagnostic testing is a promising trend, it is important to investigate PD characteristics during aging at very low frequency range. Test samples of solid insulation with voids inside fabricated by a 3D printer are subjected to VLF excitation for PD measurements. PD characteristics at different aging states of test samples are investigated under power frequency (50 Hz) and VLF excitation (0.1 Hz). PD patterns show that behaviors of discharges at 0.1 Hz and 50 Hz can be similarly categorized into 2 stages. In the first stage, electrical discharges tend to happen at high instantaneous voltage value and have large discharge magnitudes due to lack of initial free electrons at the beginning of the test. Along the testing period in the first stage, discharge magnitudes gradually decrease and PD activities happen at lower voltage value as more free electrons are available. In the second stage, PD characteristics are hardly changed. However, there is a substantial difference in time duration in the first stage between the frequency of 0.1 Hz and 50 Hz. The first stage at 50 Hz excitation is much shorter than that under VLF excitation. This could be explained by significant dependence of physical conditions such as surface conductivity of the void and charge decay mechanisms on applied frequency. At VLF, charge decay rate is higher which may cause the discharge process taking longer to finish the first stage.
{"title":"Effects of aging on partial discharge patterns in voids under very low frequency excitation","authors":"H. V. Nguyen, B. Phung, T. Blackburn","doi":"10.1109/ICD.2016.7547657","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547657","url":null,"abstract":"As the use VLF diagnostic testing is a promising trend, it is important to investigate PD characteristics during aging at very low frequency range. Test samples of solid insulation with voids inside fabricated by a 3D printer are subjected to VLF excitation for PD measurements. PD characteristics at different aging states of test samples are investigated under power frequency (50 Hz) and VLF excitation (0.1 Hz). PD patterns show that behaviors of discharges at 0.1 Hz and 50 Hz can be similarly categorized into 2 stages. In the first stage, electrical discharges tend to happen at high instantaneous voltage value and have large discharge magnitudes due to lack of initial free electrons at the beginning of the test. Along the testing period in the first stage, discharge magnitudes gradually decrease and PD activities happen at lower voltage value as more free electrons are available. In the second stage, PD characteristics are hardly changed. However, there is a substantial difference in time duration in the first stage between the frequency of 0.1 Hz and 50 Hz. The first stage at 50 Hz excitation is much shorter than that under VLF excitation. This could be explained by significant dependence of physical conditions such as surface conductivity of the void and charge decay mechanisms on applied frequency. At VLF, charge decay rate is higher which may cause the discharge process taking longer to finish the first stage.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127137903","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 : 2016-08-23DOI: 10.1109/ICD.2016.7547780
Y. Yu, B. Du, T. Han, J. Su, J. Li, J. Xue, R. L. Wang, Q. Tang, Z. Yin, F. Shen, J. Fang
Research is undertaken in this paper to clarify the effect of magnetic field (MF) direction on electrical tree propagation in silicone rubber (SiR). Needle-plate electrode is employed in the experiment. To avoid magnetic field stress on the needle electrode, this paper choose silver needles as the needle electrode, and previously placed in style. The dimension of sample is 10 mm × 10 mm × 20 mm. The distance between needle-plate electrode is 2 mm. Both repetitive pulse voltage and AC voltage is employed in the experiment. To study the effect of MF direction on the growth of electrical tree, the morphology of the electrical tree is observed from the direction of the MF and perpendicular to the MF, respectively. And the fractal dimension of the electrical tree under pulse voltage is analyzed. Obtained results show that under AC voltage, the tree morphology from two directions are similar with the increase of the magnetic flux density (MFD). Under pulse voltage, the increase of MFD can promote the growth of electrical tree in two directions. The promoting effect of the MF on the electric tree is stronger in the direction of the MF than that perpendicular to the MF.
{"title":"Effects of magnetic field direction on treeing behavior of silicone rubber","authors":"Y. Yu, B. Du, T. Han, J. Su, J. Li, J. Xue, R. L. Wang, Q. Tang, Z. Yin, F. Shen, J. Fang","doi":"10.1109/ICD.2016.7547780","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547780","url":null,"abstract":"Research is undertaken in this paper to clarify the effect of magnetic field (MF) direction on electrical tree propagation in silicone rubber (SiR). Needle-plate electrode is employed in the experiment. To avoid magnetic field stress on the needle electrode, this paper choose silver needles as the needle electrode, and previously placed in style. The dimension of sample is 10 mm × 10 mm × 20 mm. The distance between needle-plate electrode is 2 mm. Both repetitive pulse voltage and AC voltage is employed in the experiment. To study the effect of MF direction on the growth of electrical tree, the morphology of the electrical tree is observed from the direction of the MF and perpendicular to the MF, respectively. And the fractal dimension of the electrical tree under pulse voltage is analyzed. Obtained results show that under AC voltage, the tree morphology from two directions are similar with the increase of the magnetic flux density (MFD). Under pulse voltage, the increase of MFD can promote the growth of electrical tree in two directions. The promoting effect of the MF on the electric tree is stronger in the direction of the MF than that perpendicular to the MF.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123476290","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 : 2016-08-23DOI: 10.1109/ICD.2016.7547654
Yihan Zhao, Yu Chen, Lulu Wang, Attiq Ur Rehman, Yonghong Cheng, Yong Zhao, Bin Han, Toshikatsu Tanaka
Nowadays the Doubly-Fed Induction Generator (DFIG) is equipped for many large wind farms. Its faults have a deep influence on the safety and effectiveness of the machine and huge cost is required for maintenance. Investigations have revealed that stator inter-turn short circuit fault may lead to more serious problems. More researches are to focus attention on fault detection and preventive maintenance strategies for industrial plant. In this paper, an experimental platform is developed, which can conduct different stator winding inter-turn faults, and some fault feature parameters are extracted and analyzed. Stator line currents are used for calculating RMS, phase difference, negative-sequence, and the Park's vector trajectory's eccentricity as feature parameters. Stator line currents are balanced under normal condition, so the negative sequence of stator currents is almost zero, and their phase differences are about 120°. The park's vector trajectory is a circle under healthy condition, and its eccentricity is near to zero. When stator short circuit fault occurs, the negative sequence and the Park's vector trajectory's eccentricity are increasing as fault degree enlarges, and also the phase differences related to fault phase increase while the other reduces. Finally, the experimental setup simulated the expected stator inter-turn short circuit fault successfully, and the extracted feature parameters will contribute to fault diagnosis of DFIG.
{"title":"Experimental research and feature extraction on stator inter-turn short circuit fault in DFIG","authors":"Yihan Zhao, Yu Chen, Lulu Wang, Attiq Ur Rehman, Yonghong Cheng, Yong Zhao, Bin Han, Toshikatsu Tanaka","doi":"10.1109/ICD.2016.7547654","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547654","url":null,"abstract":"Nowadays the Doubly-Fed Induction Generator (DFIG) is equipped for many large wind farms. Its faults have a deep influence on the safety and effectiveness of the machine and huge cost is required for maintenance. Investigations have revealed that stator inter-turn short circuit fault may lead to more serious problems. More researches are to focus attention on fault detection and preventive maintenance strategies for industrial plant. In this paper, an experimental platform is developed, which can conduct different stator winding inter-turn faults, and some fault feature parameters are extracted and analyzed. Stator line currents are used for calculating RMS, phase difference, negative-sequence, and the Park's vector trajectory's eccentricity as feature parameters. Stator line currents are balanced under normal condition, so the negative sequence of stator currents is almost zero, and their phase differences are about 120°. The park's vector trajectory is a circle under healthy condition, and its eccentricity is near to zero. When stator short circuit fault occurs, the negative sequence and the Park's vector trajectory's eccentricity are increasing as fault degree enlarges, and also the phase differences related to fault phase increase while the other reduces. Finally, the experimental setup simulated the expected stator inter-turn short circuit fault successfully, and the extracted feature parameters will contribute to fault diagnosis of DFIG.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129653086","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 : 2016-07-03DOI: 10.1109/ICD.2016.7547797
I. A. Saeedi, A. Vaughan, T. Andritsch
Epoxy resins represent a commonly used basis for insulation materials and have been used in many different electrical applications. The formation of these systems involves reactions between a hardener, such as an amine-curing system, and an epoxy terminated resin. Recent studies have reported that epoxy resin systems can exhibit enhanced physical properties when the stoichiometry of the resin is varied using reactive diluent. This has been attributed to the increased free volume within the molecular structures within the epoxy resin network. The work described here set out to investigate this hypothesis concerning the potential benefits of varying the network structure of epoxy resin through the inclusion of monofunctional reactive diluents within the epoxy formulation. This research is of potential significance because any modification of the epoxy resin network results in modified thermal, mechanical and electrical properties and, consequently, represents a potential mean of tailoring overall performance to suit particular applications.
{"title":"On the dielectric performance of modified epoxy networks","authors":"I. A. Saeedi, A. Vaughan, T. Andritsch","doi":"10.1109/ICD.2016.7547797","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547797","url":null,"abstract":"Epoxy resins represent a commonly used basis for insulation materials and have been used in many different electrical applications. The formation of these systems involves reactions between a hardener, such as an amine-curing system, and an epoxy terminated resin. Recent studies have reported that epoxy resin systems can exhibit enhanced physical properties when the stoichiometry of the resin is varied using reactive diluent. This has been attributed to the increased free volume within the molecular structures within the epoxy resin network. The work described here set out to investigate this hypothesis concerning the potential benefits of varying the network structure of epoxy resin through the inclusion of monofunctional reactive diluents within the epoxy formulation. This research is of potential significance because any modification of the epoxy resin network results in modified thermal, mechanical and electrical properties and, consequently, represents a potential mean of tailoring overall performance to suit particular applications.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117283773","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 : 2016-07-03DOI: 10.1109/ICD.2016.7547725
Y. Liu, Yang Xiao, Yu-Hao Su, Xin Chen, Chong Zhang, Wenpeng Li
Along with its increasing application in high-voltage DC transmission network, XLPE insulated cable has become a global research hotspot. To study the cable endurance to DC operation, the initiation characteristics of electrical trees in XLPE cable insulation need to be investigated under DC voltages and design temperatures. A novel treeing test configuration, consisting of a heat oil bath, a DC voltage source and a micro-imaging system, is set up for the research on the treeing characteristics of XLPE samples under DC voltage and high temperatures. Treeing tests were performed on XLPE specimens made from a 110 kV DC cable, and each specimen has a pin-plane electrode system within. Under a continuously applied DC voltage of 60 kV for 20 days, the specimens, immerged in silicon oil heated up to 90°C, showed no electrical trees. Application of 60 kV DC voltage on specimens at room temperature for 10 days could not trigger a tree either. Under the condition of grounding after pre-stressing of a DC voltage, 20 kV was high enough to initiate a tree in the XLPE DC insulation. It is concluded that electrical treeing cannot be easily caused by constant DC voltages, even under the combined action of a high voltage and an elevated temperature. The detectable damage in XLPE insulation is a joint result of space charge's injection and extraction, and the deterioration caused by charge extraction will be more serious than injection. That is why grounding after pre-stressing can trigger a tree much easier.
{"title":"Electrical treeing test of DC cable XLPE insulation under DC voltage and high temperature","authors":"Y. Liu, Yang Xiao, Yu-Hao Su, Xin Chen, Chong Zhang, Wenpeng Li","doi":"10.1109/ICD.2016.7547725","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547725","url":null,"abstract":"Along with its increasing application in high-voltage DC transmission network, XLPE insulated cable has become a global research hotspot. To study the cable endurance to DC operation, the initiation characteristics of electrical trees in XLPE cable insulation need to be investigated under DC voltages and design temperatures. A novel treeing test configuration, consisting of a heat oil bath, a DC voltage source and a micro-imaging system, is set up for the research on the treeing characteristics of XLPE samples under DC voltage and high temperatures. Treeing tests were performed on XLPE specimens made from a 110 kV DC cable, and each specimen has a pin-plane electrode system within. Under a continuously applied DC voltage of 60 kV for 20 days, the specimens, immerged in silicon oil heated up to 90°C, showed no electrical trees. Application of 60 kV DC voltage on specimens at room temperature for 10 days could not trigger a tree either. Under the condition of grounding after pre-stressing of a DC voltage, 20 kV was high enough to initiate a tree in the XLPE DC insulation. It is concluded that electrical treeing cannot be easily caused by constant DC voltages, even under the combined action of a high voltage and an elevated temperature. The detectable damage in XLPE insulation is a joint result of space charge's injection and extraction, and the deterioration caused by charge extraction will be more serious than injection. That is why grounding after pre-stressing can trigger a tree much easier.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125315427","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 : 2016-07-03DOI: 10.1109/ICD.2016.7547776
C. Rakesh, M. J. Thomas
Pongamia oil natural esters extracted from the seeds of Pongamia Pinnata tree and its derivatives are investigated in this study to assess their suitability for use in high voltage transformers as an insulator and coolant, so as to replace the presently used mineral oil. Higher viscosity of such natural esters poses challenges for the heat transfer and impulse voltage performances, which are thought to be the major drawbacks of their use in high voltage transformers. Reducing the viscosity by chemical methods lowers the fire resistance of these natural esters. In order to obtain natural esters having balanced performance i.e. both lower viscosity and higher fire resistance, blends of Pongamia oil and low viscous fatty acid methyl ester, derived from Pongamia oil by a chemical process called trans-esterification, are prepared and their impulse voltage performance assessed. Preliminary studies conducted on Pongamia oil and its derivatives show that they can be an environmentally friendly and economically viable replacement for mineral oil used in high voltage transformers.
{"title":"Pongamia oil, an eco-friendly alternative for mineral oil used in high voltage transformers","authors":"C. Rakesh, M. J. Thomas","doi":"10.1109/ICD.2016.7547776","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547776","url":null,"abstract":"Pongamia oil natural esters extracted from the seeds of Pongamia Pinnata tree and its derivatives are investigated in this study to assess their suitability for use in high voltage transformers as an insulator and coolant, so as to replace the presently used mineral oil. Higher viscosity of such natural esters poses challenges for the heat transfer and impulse voltage performances, which are thought to be the major drawbacks of their use in high voltage transformers. Reducing the viscosity by chemical methods lowers the fire resistance of these natural esters. In order to obtain natural esters having balanced performance i.e. both lower viscosity and higher fire resistance, blends of Pongamia oil and low viscous fatty acid methyl ester, derived from Pongamia oil by a chemical process called trans-esterification, are prepared and their impulse voltage performance assessed. Preliminary studies conducted on Pongamia oil and its derivatives show that they can be an environmentally friendly and economically viable replacement for mineral oil used in high voltage transformers.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115107992","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 : 2016-07-03DOI: 10.1109/ICD.2016.7547591
G. Ortega Brana, P. Llovera-Segovia, A. Mor, M. Domínguez-Lagunilla
Cellular polymers films have a too soft mechanical characteristic, like elastic compliance due of the internal porosity structure and their high electric insulation that gives the ability of hosting internal electrical dipoles. If a corona discharge is applied to the surface, the high electrical field induces internal discharges which leave a permanent static charge in the polymer cells. A macro dipole of cell dimension is generated producing a quasi-piezoelectric response. The d33 piezoelectric constant can reach values of about many hundreds of pC/N. Thermally stimulated discharge currents (TSDC) are widely used to characterize charge density and stability of dielectric materials. In our work the relationship between TSDC and d33 piezoelectric constant of two cellular polymers based on polyethylene and polypropylene films is investigated. Samples were thermally stretched, charged by corona discharge and metallized on both sides. The d33 piezoelectric constant by quasi-static method was measured and then TSDC were registered. A strong relation between d33 constants and TSDC curves on both cellular polymers was obtained.
{"title":"Relationship between thermo-stimulated discharge currents and piezoelectric d33 constants in PP and PE foams","authors":"G. Ortega Brana, P. Llovera-Segovia, A. Mor, M. Domínguez-Lagunilla","doi":"10.1109/ICD.2016.7547591","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547591","url":null,"abstract":"Cellular polymers films have a too soft mechanical characteristic, like elastic compliance due of the internal porosity structure and their high electric insulation that gives the ability of hosting internal electrical dipoles. If a corona discharge is applied to the surface, the high electrical field induces internal discharges which leave a permanent static charge in the polymer cells. A macro dipole of cell dimension is generated producing a quasi-piezoelectric response. The d33 piezoelectric constant can reach values of about many hundreds of pC/N. Thermally stimulated discharge currents (TSDC) are widely used to characterize charge density and stability of dielectric materials. In our work the relationship between TSDC and d33 piezoelectric constant of two cellular polymers based on polyethylene and polypropylene films is investigated. Samples were thermally stretched, charged by corona discharge and metallized on both sides. The d33 piezoelectric constant by quasi-static method was measured and then TSDC were registered. A strong relation between d33 constants and TSDC curves on both cellular polymers was obtained.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122795699","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 : 2016-07-03DOI: 10.1109/ICD.2016.7547630
H. Maryono, A. Rajab, U. Khayam, Suwarno, M. Tsuchie, M. Kozako, M. Hikita, Takashi Suzuki
Palm fatty acid ester (PFAE) is mono ester oil which has better cooling property than mineral oil and other poly esters. Recently, natural ester has been tested on extra high voltage large power transformer. Large power transformers have a risk of streaming electrification. Many studies have been conducted to investigate streaming electrification properties of mineral oil immersed transformers and their countermeasures. However, streaming electrification properties of natural esters are rarely studied. Therefore, this paper presents a study on streaming electrification properties of PFAE due to aging. PFAE and mixed oils were prepared under several conditions. Aging test was conducted by heating the oil samples at 100 °C for 360, 720, 1080 and 1440 hours. The results show that heating causes various trends of volume resistivity and positive increases in electrostatic charging tendency (ECT) with respect to aging time. At initial state, ion dissociation on additive compound decreases volume resistivity and increases ECT. However, during the heating, the dissociation is not accelerated. Additive compound is dissociated into radicals to mitigate oxidation. In the mixture of 20% mineral oil and 80% PFAE, higher changes in volume resistivity and ECT indicate that degradation is more likely to occur in mineral oil part. In addition, air circumstance has effects on volume resistivity and ECT.
{"title":"Study on streaming electrification properties of palm fatty acid ester (PFAE) oil due to aging","authors":"H. Maryono, A. Rajab, U. Khayam, Suwarno, M. Tsuchie, M. Kozako, M. Hikita, Takashi Suzuki","doi":"10.1109/ICD.2016.7547630","DOIUrl":"https://doi.org/10.1109/ICD.2016.7547630","url":null,"abstract":"Palm fatty acid ester (PFAE) is mono ester oil which has better cooling property than mineral oil and other poly esters. Recently, natural ester has been tested on extra high voltage large power transformer. Large power transformers have a risk of streaming electrification. Many studies have been conducted to investigate streaming electrification properties of mineral oil immersed transformers and their countermeasures. However, streaming electrification properties of natural esters are rarely studied. Therefore, this paper presents a study on streaming electrification properties of PFAE due to aging. PFAE and mixed oils were prepared under several conditions. Aging test was conducted by heating the oil samples at 100 °C for 360, 720, 1080 and 1440 hours. The results show that heating causes various trends of volume resistivity and positive increases in electrostatic charging tendency (ECT) with respect to aging time. At initial state, ion dissociation on additive compound decreases volume resistivity and increases ECT. However, during the heating, the dissociation is not accelerated. Additive compound is dissociated into radicals to mitigate oxidation. In the mixture of 20% mineral oil and 80% PFAE, higher changes in volume resistivity and ECT indicate that degradation is more likely to occur in mineral oil part. In addition, air circumstance has effects on volume resistivity and ECT.","PeriodicalId":306397,"journal":{"name":"2016 IEEE International Conference on Dielectrics (ICD)","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121913306","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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