Pub Date : 2011-06-26DOI: 10.1109/ICDL.2011.6015414
L. Truong, D. Swaffield, P. Lewin, M. Judd
Liquid nitrogen (LN2) has been proposed as a coolant for high temperature superconducting (HTS) applications also as electrical insulation. Partial discharge (PD) activity indicates overstressing of the liquid dielectric or contamination which may provide an indication of the health of the dielectric and provide a useful precursor to the electric failure of LN2. The conventional method for PD measurements is restricted to a narrow bandwidth (less than 600 kHz). It has been shown that streamer discharges in liquid dielectrics consist of many small pulses, which due to the limited bandwidth of the PD detector would be integrated overtime by conventional equipment and recorded as single pulse [1]. The application of ultra high frequency (UHF) sensors can provide greater precision in the measurement of the discharge pulses during the pre-breakdown streamer phenomena in LN2. In addition, the UHF technique can be installed as on-line monitoring system with the capability of locating the discharge sources using the time-of-flight method, as has been proposed for oil filled transformer designs [8]. This paper explores the use of UHF sensors to measure PD in LN2. The experiments utilise point to plane electrode configuration located inside a cryostat with high voltage bushing rated to 50kV PD free [2]. The sensor is mounted on the outside wall of the cryostat with uses of dielectric windows and signals are captured by a digital oscilloscope with a bandwidth of 2.5GHz. The conventional PD technique (IEC 60270) is also applied simultaneously and the results are presented and compared.
{"title":"The feasibility of using UHF sensors to measure partial discharges in liquid nitrogen","authors":"L. Truong, D. Swaffield, P. Lewin, M. Judd","doi":"10.1109/ICDL.2011.6015414","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015414","url":null,"abstract":"Liquid nitrogen (LN2) has been proposed as a coolant for high temperature superconducting (HTS) applications also as electrical insulation. Partial discharge (PD) activity indicates overstressing of the liquid dielectric or contamination which may provide an indication of the health of the dielectric and provide a useful precursor to the electric failure of LN2. The conventional method for PD measurements is restricted to a narrow bandwidth (less than 600 kHz). It has been shown that streamer discharges in liquid dielectrics consist of many small pulses, which due to the limited bandwidth of the PD detector would be integrated overtime by conventional equipment and recorded as single pulse [1]. The application of ultra high frequency (UHF) sensors can provide greater precision in the measurement of the discharge pulses during the pre-breakdown streamer phenomena in LN2. In addition, the UHF technique can be installed as on-line monitoring system with the capability of locating the discharge sources using the time-of-flight method, as has been proposed for oil filled transformer designs [8]. This paper explores the use of UHF sensors to measure PD in LN2. The experiments utilise point to plane electrode configuration located inside a cryostat with high voltage bushing rated to 50kV PD free [2]. The sensor is mounted on the outside wall of the cryostat with uses of dielectric windows and signals are captured by a digital oscilloscope with a bandwidth of 2.5GHz. The conventional PD technique (IEC 60270) is also applied simultaneously and the results are presented and compared.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134389652","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015425
A. Khrapak, W. Schmidt
Structure and properties of positive and negative ions in liquid 4He are analyzed. The possibility of clusters or bubbles formation around impurity ions of both signs is discussed. It is demonstrated that in superfluid helium around negative alkaline-earth metal ions bubbles are formed and around halogen ions clusters are formed. The nature of “fast” and “exotic” negative ions is also discussed. It is assumed that the “fast” ions are negative ions of helium excimer molecules localized inside bubbles. The “exotic” ions are stable negative impurity ions, which are always present in small amounts in gas discharge plasma. Around such ions bubbles or clusters are created with radius smaller the radius of electron bubbles.
{"title":"Negative and positive ions in liquid helium","authors":"A. Khrapak, W. Schmidt","doi":"10.1109/ICDL.2011.6015425","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015425","url":null,"abstract":"Structure and properties of positive and negative ions in liquid 4He are analyzed. The possibility of clusters or bubbles formation around impurity ions of both signs is discussed. It is demonstrated that in superfluid helium around negative alkaline-earth metal ions bubbles are formed and around halogen ions clusters are formed. The nature of “fast” and “exotic” negative ions is also discussed. It is assumed that the “fast” ions are negative ions of helium excimer molecules localized inside bubbles. The “exotic” ions are stable negative impurity ions, which are always present in small amounts in gas discharge plasma. Around such ions bubbles or clusters are created with radius smaller the radius of electron bubbles.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123030730","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015466
D. Susa, K. Brede, L. Lundgaard
This paper discusses the field application of the improved paper filter system used for non-intrusive monitoring of power transformer insulation contamination level. The filter has been applied to three transformer units. The first results indicated promising trend between the levels of the measured contamination and ageing accelerators in the filter and in the transformers. Also, the monitoring procedures are further discussed to improve measuring consistency.
{"title":"On-line assessment of power transformer ageing accelerators","authors":"D. Susa, K. Brede, L. Lundgaard","doi":"10.1109/ICDL.2011.6015466","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015466","url":null,"abstract":"This paper discusses the field application of the improved paper filter system used for non-intrusive monitoring of power transformer insulation contamination level. The filter has been applied to three transformer units. The first results indicated promising trend between the levels of the measured contamination and ageing accelerators in the filter and in the transformers. Also, the monitoring procedures are further discussed to improve measuring consistency.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129367709","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015437
V. Madhurima, D. Purkayastha, K. Sudheendran, K. Raju
Theoretical contact angle of Diiodomethane on Bismuth Zinc Niobate thin film on fused silica substrate is calculated and the results are compared with experimental values. The theoretical calculation of contact angle is by the determination of the Hamaker's constant from the dielectric data and applying Lifshitz-van der Waals dispersive interaction and Young-Dupree equation and the experimental value is found using a contact angle goniometer using the sessile drop method. The results from the experiment were seen to be close to that from the theoretical calculation.
计算了二碘甲烷在熔融石英衬底铌酸铋锌薄膜上的理论接触角，并与实验结果进行了比较。接触角的理论计算是由介电数据确定Hamaker常数，应用Lifshitz-van der Waals色散相互作用和Young-Dupree方程，用接触角测角仪用固滴法求出实验值。实验结果与理论计算结果接近。
{"title":"A correlation between dielectric permittivity and wettability for low energy surface (Bismuth Zinc Niobate) on fused silica","authors":"V. Madhurima, D. Purkayastha, K. Sudheendran, K. Raju","doi":"10.1109/ICDL.2011.6015437","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015437","url":null,"abstract":"Theoretical contact angle of Diiodomethane on Bismuth Zinc Niobate thin film on fused silica substrate is calculated and the results are compared with experimental values. The theoretical calculation of contact angle is by the determination of the Hamaker's constant from the dielectric data and applying Lifshitz-van der Waals dispersive interaction and Young-Dupree equation and the experimental value is found using a contact angle goniometer using the sessile drop method. The results from the experiment were seen to be close to that from the theoretical calculation.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131320265","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015435
S. Barringer, Kumala Marthina
In the chocolate coating industry, cocoa butter is a high value ingredient. Due to high cost, shortage of supply and blooming, hard butters are frequently used as cocoa butter replacers. An electrohydrodynamic system (EHD), which forms fine droplets with a relatively narrow size distribution, may be beneficial in confectionary coating to reduce cost and to increase quality because complete and even coverage can be achieved. The objective of this research is to optimize the use of EHD by altering the resistivity, viscosity and yield stress of different types of confectionery coating using lecithin. Non-EHD and EHD coating systems using confectionary coating made of cocoa butter equivalent, lauric cocoa butter or cocoa butter with different percentages of lecithin were analyzed. Droplet size, thickness of coating and minimum flow rate to produce complete coverage was measured. The voltage supplied for EHD coating system was 25kV. As lecithin increased, resistivity, viscosity and yield stress of samples decreased. Lower resistivity, viscosity and yield stress samples produced smaller droplet size, thinner coating and higher minimum flow rate. EHD coating is more efficient than non-EHD coating because more even and complete coverage can be achieved as fine droplets are produced and distributed during coating. The droplet size was significantly smaller for samples sprayed with EHD compared to non-EHD. The thickness was significantly lower under EHD and the minimum flow rate to get complete coverage with EHD was greater because EHD coating tends to spread over a wider area. Under EHD coating, samples with lower resistivity produced smaller droplet size and lower thickness, which is important to reduce cost and increase quality of coated food products.
{"title":"Confectionary coating using an electrohydrodynamic system","authors":"S. Barringer, Kumala Marthina","doi":"10.1109/ICDL.2011.6015435","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015435","url":null,"abstract":"In the chocolate coating industry, cocoa butter is a high value ingredient. Due to high cost, shortage of supply and blooming, hard butters are frequently used as cocoa butter replacers. An electrohydrodynamic system (EHD), which forms fine droplets with a relatively narrow size distribution, may be beneficial in confectionary coating to reduce cost and to increase quality because complete and even coverage can be achieved. The objective of this research is to optimize the use of EHD by altering the resistivity, viscosity and yield stress of different types of confectionery coating using lecithin. Non-EHD and EHD coating systems using confectionary coating made of cocoa butter equivalent, lauric cocoa butter or cocoa butter with different percentages of lecithin were analyzed. Droplet size, thickness of coating and minimum flow rate to produce complete coverage was measured. The voltage supplied for EHD coating system was 25kV. As lecithin increased, resistivity, viscosity and yield stress of samples decreased. Lower resistivity, viscosity and yield stress samples produced smaller droplet size, thinner coating and higher minimum flow rate. EHD coating is more efficient than non-EHD coating because more even and complete coverage can be achieved as fine droplets are produced and distributed during coating. The droplet size was significantly smaller for samples sprayed with EHD compared to non-EHD. The thickness was significantly lower under EHD and the minimum flow rate to get complete coverage with EHD was greater because EHD coating tends to spread over a wider area. Under EHD coating, samples with lower resistivity produced smaller droplet size and lower thickness, which is important to reduce cost and increase quality of coated food products.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132770047","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015450
Hans-Peter Gasser, C. Krause, M. Lashbrook, Russell Martin
Today, the transformer industry uses alternative insulating liquids more and more. Possible alternatives are vegetable esters such as rape seed, soy bean or sunflower oils or synthetic esters. The aim is to replace the flammable and environmentally harmful mineral oils. Another advantage of these liquids is the higher water solubility, which is claimed to be responsible for a reduced aging rate of cellulosic insulation compared to mineral oil.
{"title":"Aging of pressboard in different insulating liquids","authors":"Hans-Peter Gasser, C. Krause, M. Lashbrook, Russell Martin","doi":"10.1109/ICDL.2011.6015450","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015450","url":null,"abstract":"Today, the transformer industry uses alternative insulating liquids more and more. Possible alternatives are vegetable esters such as rape seed, soy bean or sunflower oils or synthetic esters. The aim is to replace the flammable and environmentally harmful mineral oils. Another advantage of these liquids is the higher water solubility, which is claimed to be responsible for a reduced aging rate of cellulosic insulation compared to mineral oil.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130716954","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015474
A. Ghani, Z. Zarim, Jazimah Abdul Majeed, H. Osman
Gas-in-fluid analysis refers to dissolved gas analysis (DGA). DGA facilitates the observation of the by-products of the oil degradation through its environment, the insulating and pressurizing fluid. The three main degradation processes that generate gases are thermal degradation, partial discharge and arcing. The most significant gases generated from oil decomposition are hydrogen gas (H2), methane (CH4), ethane (C2H6), ethylene (C2H4) and acetylene (C2H2) [3]. The measurements of dissolve gas (DG) were made for the medium voltage oil-filled cable. Partial discharge (PD) measurement was done the MV oil-filled cable to determine the level of PD activities. The correlation of PD magnitude and DGA level were established to determine the severity of the results and for diagnostic purposes. The measurement of moisture contents in the insulating oil was made using Karl Fisher method.
{"title":"Diagnostic criteria based on the correlation of the measurement of DGA, moisture contents with PD & tan d in MV oil-filled underground cable","authors":"A. Ghani, Z. Zarim, Jazimah Abdul Majeed, H. Osman","doi":"10.1109/ICDL.2011.6015474","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015474","url":null,"abstract":"Gas-in-fluid analysis refers to dissolved gas analysis (DGA). DGA facilitates the observation of the by-products of the oil degradation through its environment, the insulating and pressurizing fluid. The three main degradation processes that generate gases are thermal degradation, partial discharge and arcing. The most significant gases generated from oil decomposition are hydrogen gas (H2), methane (CH4), ethane (C2H6), ethylene (C2H4) and acetylene (C2H2) [3]. The measurements of dissolve gas (DG) were made for the medium voltage oil-filled cable. Partial discharge (PD) measurement was done the MV oil-filled cable to determine the level of PD activities. The correlation of PD magnitude and DGA level were established to determine the severity of the results and for diagnostic purposes. The measurement of moisture contents in the insulating oil was made using Karl Fisher method.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"480 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116362434","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015442
Yunus Biçen, Yusuf Cilliyuz, F. Aras, Guzide Aydugan
This paper presents an assessment on aging model of IEEE and IEC standards using thermal model of oil-immersed power transformer for natural ester and mineral oil. For this purpose, a model created for the analysis of behavior transient thermal performance with aging both of natural ester and mineral oils. Thermal model of the transformer is based on thermal-electrical analogy that is calculated separately for natural and mineral oils covering top-oil and hot-spot temperatures. The hot-spot temperature values of each ester/oil are used to calculate aging parameters which include the aging acceleration factor, time dependent relative aging rate and insulation life loss variations.
{"title":"An assessment on aging model of IEEE/IEC standards for natural and mineral oil-immersed transformer","authors":"Yunus Biçen, Yusuf Cilliyuz, F. Aras, Guzide Aydugan","doi":"10.1109/ICDL.2011.6015442","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015442","url":null,"abstract":"This paper presents an assessment on aging model of IEEE and IEC standards using thermal model of oil-immersed power transformer for natural ester and mineral oil. For this purpose, a model created for the analysis of behavior transient thermal performance with aging both of natural ester and mineral oils. Thermal model of the transformer is based on thermal-electrical analogy that is calculated separately for natural and mineral oils covering top-oil and hot-spot temperatures. The hot-spot temperature values of each ester/oil are used to calculate aging parameters which include the aging acceleration factor, time dependent relative aging rate and insulation life loss variations.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126622425","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015447
R. Eberhardt, B. Wieser, W. Lick, H. Muhr, G. Pukel, Robert Schwarz, F. Baumann
To offer more personal safety and a better environmental behavior of electrical power supply, the usage of alternative insulation fluids is demanded in large power transformers. The minimizing of fire loads is another significant reason for these new liquids. A number of companies are offering such alternative insulation fluids which are already used in distribution transformers but there is still little experience with those liquids in large power transformers. One reason for this is missing maintenance information like limit values of the different DGA detectable gasses. For mineral oil there are many different interpretation methods for DGA (Dissolved Gas Analysis) results and also many known patterns for specific reasons of the increase of one or more gas values. This investigation shows which gas values change significantly caused by breakdown in an oil/cellulose insulation system resp. an ester/cellulose system. A test setup was created and experiments were done with mineral oil, a natural ester and a synthetic ester. A DGA analysis was carried out before and after several breakdowns in the liquids. With the results the gasses which indicate an oil/cellulose breakdown could be identified.
{"title":"Dissolved gas analysis investigations on ester liquids after breakdown","authors":"R. Eberhardt, B. Wieser, W. Lick, H. Muhr, G. Pukel, Robert Schwarz, F. Baumann","doi":"10.1109/ICDL.2011.6015447","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015447","url":null,"abstract":"To offer more personal safety and a better environmental behavior of electrical power supply, the usage of alternative insulation fluids is demanded in large power transformers. The minimizing of fire loads is another significant reason for these new liquids. A number of companies are offering such alternative insulation fluids which are already used in distribution transformers but there is still little experience with those liquids in large power transformers. One reason for this is missing maintenance information like limit values of the different DGA detectable gasses. For mineral oil there are many different interpretation methods for DGA (Dissolved Gas Analysis) results and also many known patterns for specific reasons of the increase of one or more gas values. This investigation shows which gas values change significantly caused by breakdown in an oil/cellulose insulation system resp. an ester/cellulose system. A test setup was created and experiments were done with mineral oil, a natural ester and a synthetic ester. A DGA analysis was carried out before and after several breakdowns in the liquids. With the results the gasses which indicate an oil/cellulose breakdown could be identified.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126627769","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015050
I. Liapis, M. Danikas
The aim of this paper is the study of various parameters affecting the ageing of transformer oil in distribution transformers of 20/0.4 kV. 69 samples of oil were taken from such transformers. The transformers function in the major Athens area, Greece. Parameters, such as breakdown strength (measured with a Foster test cell, according to IEC 156/95), oil colour (with a chromometer than meets the specifications DIN 51517-ASTM 155), humidity (measured with the Karl-Fischer method, according to IEC 814), interfacial tension (which is of importance especially in the early stages of ageing, measured according to ASTM D971-91) and tanδ (with a system counting tanδ values with maximum accuracy from 0.00001 to 4.0, measured according to IEC 247) were taken into account. Transformer ageing is strictly related to the rate of ageing of the whole insulating system, and mainly of the oil.
{"title":"A study of parameters affecting the ageing of transformer oil in distribution transformers","authors":"I. Liapis, M. Danikas","doi":"10.1109/ICDL.2011.6015050","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015050","url":null,"abstract":"The aim of this paper is the study of various parameters affecting the ageing of transformer oil in distribution transformers of 20/0.4 kV. 69 samples of oil were taken from such transformers. The transformers function in the major Athens area, Greece. Parameters, such as breakdown strength (measured with a Foster test cell, according to IEC 156/95), oil colour (with a chromometer than meets the specifications DIN 51517-ASTM 155), humidity (measured with the Karl-Fischer method, according to IEC 814), interfacial tension (which is of importance especially in the early stages of ageing, measured according to ASTM D971-91) and tanδ (with a system counting tanδ values with maximum accuracy from 0.00001 to 4.0, measured according to IEC 247) were taken into account. Transformer ageing is strictly related to the rate of ageing of the whole insulating system, and mainly of the oil.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123823930","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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