Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.最新文献

{"title":"A comparison between partial discharge propagation in multiple-/spl alpha/ and single-/spl alpha/ transformer winding","authors":"M. Vakilian, T. Blackburn, B. Phung, H. Zhang, O.H. Nam, M. S. Naderi","doi":"10.1109/EEIC.2005.1566269","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566269","url":null,"abstract":"Power transformers are in service in different environmental, electrical and mechanical conditions. Many experiences have proved that the inner insulation system degradation may pose the transformer to fail while in service. On the other hand, partial discharges (PD) are recognized as the main cause of insulation deterioration process. Therefore, reaching the optimum inner insulation system is one of the challenges a transformer designer is faced with. The solution lies in the correct and accurate modelling of different types of transformer windings. Transformer strength especially during transient conditions is a criterion for transformer insulation designers. This challenge has made designers switch from ordinary layer and disc windings to multiple-alpha windings. Multiple-alpha windings have more complicated structure and comprise various parts with different physical structure and electrical characteristic. These kinds of windings have usually more wire length. These characteristics make partial discharge measurements be more hassling. Partial discharges that take place inside the winding propagate along the winding to reach the measuring terminals. Typical partial discharge signals cover a wide frequency range from DC up to hundreds of MHz and different frequency components propagate through the winding depending upon the winding structure in different modes. In this paper a comparison has been made between the results gained when the winding is single-alpha and those of multiple-alpha. A 66 kV/25 MVA interleaved winding, which has 19 fully interleaved discs plays the role of a single-alpha winding. When this main winding is connected to the tap winding with different structure and magnitude response, a multiple-alpha winding is constructed. In the experimental measurements in the laboratory, the line and neutral-end current signals are detected by two home-made high frequency current transformers (HF-CT) and recorded with a 500 MHz digital oscilloscope. Home-made sensors are designed to provide maximum sensitivity in the desired frequency range","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115911389","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}

{"title":"Temperature calculation of power cable conductor in real time","authors":"Junhua Luo, Yi-gang Liu, Y. Luo","doi":"10.1109/EEIC.2005.1566251","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566251","url":null,"abstract":"The node voltage method is widely used to solve electric circuit problems. It is also an effective method to set up and calculate power cable thermal conditions because the equivalent thermal circuit of a power cable is mathematically similar to an electric circuit. According to real time measurement results of polymeric jacket temperatures of power cables, the temperature of the cable conductor may be calculated using the node voltage method. Furthermore, the power cable load current can be controlled in real time based upon the conductor temperature","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121075440","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}

{"title":"A new diagnostic tool for preventive maintenance on large generators-PD location in stator windings by the traveling wave method","authors":"R. Koch, F. Pohlmann, J. R. Weidner","doi":"10.1109/EEIC.2005.1566261","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566261","url":null,"abstract":"The development of cost-effective maintenance strategies requires diagnostic tools which detect any defects as early as possible to enable the determination and selective planning of the requisite repair measures. The sensitive partial discharge (PD) measurement method enables the detection of individual weak points developing in generator high voltage stator insulation in their initial stages. However, a reliable evaluation also requires the most exact possible knowledge of the location of the insulation where partial discharge occurs. The following paper presents a method enabling the precise localization of internal partial discharges in the shielded slot section of stator windings based on the localization principle of transit time difference measurement between the two sides of the stator core. The PD pulses are decoupled from the winding bars using a patented new type of sensor, digitized at a high sampling rate of 4 GS/s and subjected to mathematical analysis. Measurements on old winding bars from large generators and on complete stator windings (40-1640 MVA) yield high localization accuracies within the range of centimeters. In a rewound 880 MVA generator with an active core length of 6.6 m, a partial discharge source was localized which could not be detected by conventional equipment at the generator terminals. This demonstrates the excellent sensitivity of the new diagnostic tool","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131925648","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}

{"title":"An evaluation of diagnostic techniques relevant to arcing fault current interrupters for direct current power systems in future aircraft","authors":"R. Spyker, D. Schweickart, J. Horwath, L. Walko, D. Grosjean","doi":"10.1109/EEIC.2005.1566277","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566277","url":null,"abstract":"Arc fault circuit interrupters (AFCI) are a relatively new development in the area of circuit protection. Typical circuit breakers are designed to detect an overload current in the protected circuit and trip open within a specified period of time. The AFCI is a device that detects and interrupts an arcing fault when it occurs. An arc fault is a dangerous situation with very high temperatures in the arc. These high temperatures are sufficient to ignite wire insulation and other combustibles in the vicinity of the arc. Standard circuit breakers and ground fault circuit breakers generally will not trip in the event of an arc fault since there is sufficiently high impedance in the circuit to limit current below the trip level of its characteristic curve. Numerous arc faults that have been observed on aging aircraft, due to failing insulation, have spurred an interest in AFCIs for both commercial and military aircraft. Such AFCIs assess the AC current waveform to distinguish that an arc is occurring in the circuit. When this occurs, the AFCI will open to mitigate damage to the wiring system. In the AC case, the opening device will generally take advantage of the natural current zero in the AC wave form to clear the circuit. Protective devices for DC systems cannot exploit this characteristic. In addition, the charge transport properties (conductivity) of the DC arc are affected by the gas density (i.e., altitude) surrounding the arc. This paper presents experimental results intended to help evaluate the potential applicability of the typical diagnostics used in AC AFCIs as a valid means of detecting a series DC arc. This is particularly relevant to future aircraft power systems employing 270 Volt DC distribution. Also, these DC arcs have been characterized at low atmospheric pressures to simulate high altitude operation","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133605634","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}

{"title":"Study of on-line monitoring method of partial discharge for power transformers based on RFCT and microstrip antenna","authors":"Cheng Yonghong, Chen Yu, Liu Tong, Xun Xiaowei, Ji Linlie, Chen Wei, Chen Lixin","doi":"10.1109/EEIC.2005.1566268","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566268","url":null,"abstract":"It is an important means for partial discharge (PD) on-line monitoring of oil-immersed power transformers in order to evaluating the insulation condition. Radio frequency current transducers (RFCT) are applied to couple the PD pulse current signal, and the difference-balance pairs (one of three-phase bushing-tap grounding terminals respectively corresponded with the neutral or iron core terminal) are selected, and high speed data acquisition card is adopt to sample the PD signal (>10MS/s) from the balance pair, and further amplitude modulation, phase modulation and difference arithmetic is designed, then external electromagnetic interference is effectively suppressed and it is propitious to extracting PD pulses and judge the PD occurrence place. The wideband PD couplers based on microstrip antenna are also applied to detect the high frequency PD pulse signal. Four sensors are installed at the special parts on the transformer where PD electromagnetic wave signal can be received, then the signal is transmitted to the input analog channel of the oscilloscope (>IGS/s). So single PD waveform analysis throughout more wide frequency band can be done, and further PD fault location can also be realized. The PD on-line monitoring system based on the above two monitoring methods for in-service transformer has also been developed and installed at one main transformer in a plant (220/18RV, 360MVA, three phase and dual winding)","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122825544","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}

{"title":"An ultracapacitor-powered race car update","authors":"P. Carter, J. Baxter, T. Newill, T. Erekson","doi":"10.1109/EEIC.2005.1566305","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566305","url":null,"abstract":"In 2004 BYU researchers reported on a General Motors EV1 vehicle that they received from G.M. and modified to run on ultracapacitors. The EV1 set a world's record as the fastest modified-production electric vehicle in national competition, as well as the world's only reported capacitor-powered race car. During the past year planned modifications have been implemented and the car has broken its previous record by 1.8 seconds. This paper summarizes the changes that were made and presents the most recent race results","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131543018","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}

{"title":"Measurement and analysis of partial discharge in switchgear","authors":"C. Kane, I. Blokhintsev, A. Golubev","doi":"10.1109/EEIC.2005.1566291","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566291","url":null,"abstract":"Partial discharge technology has been applied to medium voltage rotating machines for many years. This technology can now be applied to support on-line diagnostics of medium voltage switchgear assemblies. Partial discharge sensors have been developed, with calibration both in the factory-test floor environment, as well as in the field under normal operating conditions. The application of partial discharge measurement technology to MV switchgear will be presented, with actual examples of pending failures, which were identified by on-line partial discharge measurements. This application of partial discharge technology can greatly aid in the day-to-day reliability and life-extension of the medium voltage electrical power substation assemblies","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132351293","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}

{"title":"Thermally upgraded insulation in transformers","authors":"T. Prevost","doi":"10.1109/EEIC.2005.1566272","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566272","url":null,"abstract":"This paper will review the development of thermally upgraded paper. It will discuss the various chemical modifications developed and give the current processes used today. It will review current standards activities which deal with thermally upgraded insulation systems and their impact on the recommended loading practices of transformers. It will also review the effect of thermal upgraded insulations on diagnostic techniques such as gas-in oil analysis of furanic compounds and their indication of insulation degradation. Finally recent aging tests will be presented which correlate aging rates as a function of the degree of thermal upgrading measured by the nitrogen content of the paper","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126357319","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}

{"title":"A suggested approach for specifying partial discharge testing as a new winding acceptance test","authors":"G. Stone","doi":"10.1109/EEIC.2005.1566280","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566280","url":null,"abstract":"Partial discharge testing has been used for over 50 years as a diagnostic to assess the insulation condition of motor and generator stator windings rated 3.3 kV and above. As such, most of the North America's large utility generators already undergo routine on-line PD testing. Many users have expressed a desire to specify allowable PD levels for new stators or rewinds-to ensure acceptable manufacturing and assembly of the winding, especially for global VPI stators. Unfortunately there are no domestic or international standards that describe the acceptable PD levels. If PD tests are to be used as acceptance tests-then the users must insert this in their purchase specifications. One must be very careful when specifying PD for a new machine-to ensure that the test is both meaningful, yet not unreasonably difficult to pass. This paper reviews the reasons for this, and proposes a scientifically defensible way of specifying PD, that is independent of the test equipment used","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125572786","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}

{"title":"Prototypes of polymer-impregnated reforested wood crossarms subjected to partial discharge tests","authors":"R. Altafim, R. Woschitz, C. Ribeiro, M. Muhr, J.F.R. Silva, C. Calil, H. C. Basso, C. Sumereder, R. Altafim, A. Silveira","doi":"10.1109/EEIC.2005.1566295","DOIUrl":"https://doi.org/10.1109/EEIC.2005.1566295","url":null,"abstract":"Brazil's vast territory and huge forested regions have contributed to the widespread use of traditional crossarms made of native wood species in distribution lines. However, this situation is changing due to the increasingly high cost of native species and Brazil's environmental laws. In response to these changes, electric power suppliers have been seeking alternatives, and prototypes of reforested wood crossarms (such as Eucalyptus citriodora) impregnated with polymer (castor oil-based polyurethane resin) have been studied for application as mechanical supports for electrical power distribution systems, with very satisfactory results. This paper discusses mechanical and electrical tests conducted on this new material under critical conditions of temperature and relative air humidity. Also presented are the results of electrical tests conducted at Graz Technology University's Institute of High Voltage Engineering and System Management in Austria to analyze the material's insulation performance under electrical stress particularly under partial discharge during critical operating conditions","PeriodicalId":267510,"journal":{"name":"Proceedings Electrical Insulation Conference and Electrical Manufacturing Expo, 2005.","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126850094","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}