2020 IEEE Electrical Insulation Conference (EIC)最新文献

{"title":"Application of Heat Pipe Technology on Averaging Temperature of UHV Converter Valve-Side Bushing","authors":"Ming Chen, Xuandong Liu, Xing Fan, Qiaogen Zhang, Chengjun Liang, Yi Zhao","doi":"10.1109/eic47619.2020.9158754","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158754","url":null,"abstract":"As a critical component of UHV converter transformer, the converter valve-side bushing plays a vital role in connecting HVAC and HVDC systems. Due to the poor radial heat dissipation of the UHV converter valve-side bushing, the overall temperature and electric field distribution are incredibly uneven, especially under the condition of high ambient temperature and heavy load. To improve the temperature distribution and transmission capacity of the UHV converter valve-side bushing, we proposed the heat pipe method of averaging temperature, whose main principle is to realize superconductivity by using the phase-change effect of working medium. An electro-thermal-fluid coupled simulation model considering phase-change effect is established for a ±500 kV converter valve-side bushing. Corresponding electric field distribution and temperature distribution are obtained under conditions of different carrying current. The results show that the conductor structure of the UHV converter valve-side bushing perfectly conforms to the structure of the heat pipe. Besides, the application of heat pipe technology can significantly reduce the hot spot temperature, average the axial temperature, and increase the current-carrying capacity of the UHV converter valve-side bushing.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126458233","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 Study of the Pulse Propagation Behavior in a Large Turbo Generator","authors":"M. Lachance, F. Oettl","doi":"10.1109/eic47619.2020.9158584","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158584","url":null,"abstract":"The experiment described in this paper was performed to gain a better understanding of the partial discharge (PD) pulse propagation behavior in the stator winding of a large turbo generator. The winding insulation was drilled at several locations in the slot section and in the end-winding area. A PD calibrator was used to inject artificial PD pulses at these locations. The pulses were then measured at different sites, including at the line terminal, using both a frequency-selective PD measurement system and a wideband digital oscilloscope. The results are displayed using an attenuation matrix where a normalized measured quantity is plotted as a function of distance from the sensor. Several different frequency bandwidths were used to demonstrate the advantages of the apparent charge measurement in the low frequency range. Two main pulse propagation modes are discussed in this paper: a) a slow mode and b) a fast mode. Different examples are used to show the effects of pulse attenuation and cross-coupling between bars in the end-winding area. In addition, some common industry practices related to PD measurement on stator windings are briefly discussed.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131184373","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":"Laboratory Testing Results Of Vintage Medium Voltage Nuclear Power Plant Cables","authors":"Bryan Mcconkey, T. Toll, P. Ward, C. Ferree","doi":"10.1109/eic47619.2020.9158764","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158764","url":null,"abstract":"All nuclear power plants (NPPs), and other types of industrial facilities, over time suffer from faults and operating issues in cable circuits, connectors, shielding, and end devices while in service. These types of issues occur in both low voltage (LV) and medium voltage (MV) circuits, and a wide range condition monitoring (CM) technologies have been developed to identify, locate, and quantify the severity of age-related degradation that occurs in these systems and components. In general, the degradation and failure mechanisms that occur in MV cable circuits can be significantly different than those that occur in low voltage (LV) cables. One of the primary concerns of MV cables installed in NPPs is moisture related degradation that can cause a buildup of localized electrical stresses in the cable insulation polymer. These electrical stresses can lead to the formation and growth of water trees and/or electrical trees in the insulation and cause partial discharges to occur in the cable polymer. Over time, these moisture related issues can cause degradation of the insulation material and/or cable failure. As NPPs and other industrial facilities age, identifying, locating, and quantifying degradation in systems important to safety, operation and production along with their associated cables is becoming a higher priority for long term reliability. This paper presents the results and findings of a cable condition assessment that was performed using laboratory CM techniques to assess the aged condition of six (6) 5 kV MV cable samples removed from service at an operating nuclear power plant. During operation, these six (6) samples and other sections of this cable were submerged in water, and after nearly forty years of service had noticeable signs of moisture intrusion into the cable (e.g. low insulation resistance measurements and swelling and blistering of the cable jacket). Based on the results of the laboratory condition assessment, the jacket and insulation materials of these cable samples are susceptible to moisture related degradation, which can lead to water/electrical tree formation and growth in the cable insulation. These types of issues lead to degradation of the electrical properties of the cable (e.g. decreasing insulation resistance) and can eventually cause cable failure.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127804960","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 Track Towards Unsupervised Partial Discharge Inference in Electrical Insulation Systems","authors":"R. Ghosh, P. Seri, G. Montanari","doi":"10.1109/EIC47619.2020.9158742","DOIUrl":"https://doi.org/10.1109/EIC47619.2020.9158742","url":null,"abstract":"Measuring partial discharges in electrical insulation systems is becoming a standard procedure for quality control, qualification and commissioning of electrical apparatus. Even more important, partial discharges are the main property to be monitored to assess the health conditions of any organic insulation system. However, large part of the potentiality offered by partial discharge measurements is hindered by the need of experts to record, process and interpret data, which delays and even prevent from the diffusion of this diagnostic property. This paper presents a new algorithm which seems to be very effective in providing automatic separation of partial discharges from noise, which is the first step to develop a fully automatic and unsupervised diagnostic approach. Multi-dimensional signal decomposition is achieved resorting to various transformation applied to recorded pulses, including time and frequency domains, and entropy. Clusters thus obtained are separated by statistical and artificial intelligence algorithms. Applications to AC sinusoidal voltage supply are presented, highlighting that the proposed approach is valid also under DC and power electronics supply.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116962593","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":"Improvements in Direct Current Stator Winding Insulation Testing","authors":"M. Šašić, H. Sedding, G. Stone","doi":"10.1109/eic47619.2020.9158653","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158653","url":null,"abstract":"Direct Current (DC) high voltage testing is frequently used to assess the condition of stator windings. The list of the reasons why DC tests may be preferred over alternating 50 Hz or 60 Hz voltage tests is long: smaller size of the test equipment, fewer partial discharges, less risk of damage in the case of very poor insulation quality. Different direct current test methods are possible such as DC HIPOT, polarization index test, ramped voltage test, uniform time and graded time voltage step test, insulation profiling, etc. Since the traditional DC hi-pot test is not a diagnostic test (the result of the test is either PASS or FAIL), an improved method of DC testing using ramped direct high voltage was introduced by Bruce McHenry in 1964 [6] and this paper describes the differences between the two ramped direct-high voltage methods proposed in IEEE 95.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125932791","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":"Investigation of X- Wax Formation in Power Transformers under Operating Conditions","authors":"M. Kuhnke, P. Werle, A. Sbravati, K. Rapp","doi":"10.1109/EIC47619.2020.9158704","DOIUrl":"https://doi.org/10.1109/EIC47619.2020.9158704","url":null,"abstract":"Wax-formation in electrical equipment is usually associated with oil impregnated cables and capacitors. Its formation is generally attributed to high field strength and partial discharges. In context with power transformers x-wax only appeared in the bushings. In recent years, however, there was an increasing number of failures in hermetically sealed power transformers with wax formation in the high voltage windings. Wax formation in transformers may block the cooling ducts and lead to overheating. Especially compact power transformers with synthetic ester and silicone fluid seem to be affected. This investigation sought the necessary conditions under which x-wax is formed in power transformers and how these conditions differ for different types of insulation liquids. A laboratory model of the high voltage insulation of a distribution transformer is used to investigate the influence of temperature, partial discharges (PD) and pressure on the x-wax formation. In hermetically sealed transformers the internal pressure can change depending on the load and ambient conditions. Previous investigations have shown that small reduction of the internal pressure can significantly reduce PD inception voltage and increase the apparent charge of the PDs. This is a transient situation that may happen in wind turbine transformers when the transformer cools down during a calm phase. For this study, different insulation fluids, such as synthetic and natural esters, silicone fluid and mineral oil are stressed with partial discharges for 200 hours at various temperatures both at ambient pressure and at a reduced pressure of approx. 800 mbar. The partial discharges are monitored to allow a comparison between the PD energy and the amount of wax formed during the experiment. The overall behavior of the PD was quite different with the different liquids, requiring an increasing voltage to keep igniting in the case of natural ester. Dissipation factor, permittivity, DC resistance and breakdown voltage of the fluids are measured before and after the PD stress to see if these can be used as indicators for wax generation. The investigation shows, that, when stressed with partial discharges over extended periods of time, all insulation fluids form some sort of solid ageing product, which are being investigated and may or may not be classified as x-wax. The amount of solid and the conditions under which they are formed differs greatly according to type of the fluid.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128714651","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":"In situ defect recognition analysis on long cables through nondestructive reflectometry and dielectric spectroscopy methods: a comparison","authors":"S. V. Suraci, D. Fabiani, J. Cohen","doi":"10.1109/eic47619.2020.9158583","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158583","url":null,"abstract":"In this paper the aging through high temperature of 10-meter long coaxial cables and its change in electrical properties have been investigated through non-destructive electrical techniques i.e. dielectric spectroscopy and time domain reflectometry. Both techniques allow changes of electrical properties to be revealed with aging, however, the coupling of these two techniques permits an effective cable aging assessment allowing also the recognition of local defects. Indeed, it has been demonstrated that dielectric spectroscopy is more sensitive when the cable is globally aged, while time domain reflectometry, in addition to a global investigation, can also single out aging occurring in limited portion of cable insulation (local aging).","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128261549","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":"New Breakdown Calculation Method for Gas-insulated High Voltage Applications","authors":"Andreas Hopf, M. Rossner, F. Berger, A. Küchler","doi":"10.1109/eic47619.2020.9158770","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158770","url":null,"abstract":"This contribution is focused on a new calculation method of the breakdown voltage i.e. the dielectric strength of gases in dependence of pressure, distance and arbitrary electrode and electric field arrangement, within the weakly inhomogeneous electric field. This breakdown voltage calculation is based on the well-known criterion according Townsend and Raether with the theory of charge carrier multiplication by impact ionization. The enhancement of these theories is the iterative calculation of the streamer propagation in gases with a superimposed electric field strength in addition to the background field. Furthermore, the model of the streamer gets enhanced by Paschen's gas parameter A to achieve a dependence on pressure. This new breakdown voltage calculation algorithm requires the distribution of the electric field along its critical breakdown path, e.g. from a FEM simulation. The algorithm is based on a huge database of breakdown measurements of SF6, synthetic air, N2, CO2 with a variation of pressure and sparking distance $({p}=mathbf{0.1}ldots mathbf{2.6 MPa}, {d}=mathbf{0.5}ldots mathbf{45 mm})$ at AC and DC voltages up to 300 kV and LI voltages up to 750 kV. According to this new algorithm a mathematical term is extracted which combines the theories of Schwaiger and Paschen to simplify calculations when FEM field simulation is done. For this a new notion of the ignition field strength $overline{E}_{mathrm{i}}$ is introduced. This method improves and simplifies breakdown calculations in gases by reducing the time effort. A verification of this calculation methods was done by measurements in laboratory measurements up to 750 kV and 2.6 MPa.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132173822","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":"Optimal Design of Insulation Structure of HV-HF Transformer Based on High-Frequency Insulation Properties of Gas-Solid System","authors":"Yikun Zhao, Guoqiang Zhang, Zhenghai Liao, Liujie Wan, Yanfei Li, Fuyao Yang","doi":"10.1109/eic47619.2020.9158702","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158702","url":null,"abstract":"Although the increase in frequency brings many advantages such as the higher transmission efficiency and lower volume for high-voltage high-frequency (HV-HF) transformers, the insulation performance of dielectric is noticeable degraded. Through a high-frequency test platform, the insulation tests on gas-solid insulation system were performed under the frequency of 1 kHz~20 kHz. The breakdown characteristic of polyimide films in air and the flashover characteristic of gas-solid insulation system were studied. Subsequently, the insulation structure of the dry-type HV-HF transformer was designed in consideration of volume and insulation performance. Finally, the applied voltage withstand test was performed on a simple dry-type transformer model. Experimental results show that the applied voltage vs. durable time $({V}-{t})$ curves of polyimide films shift with the increase of frequency due to the high-frequency thermal effect, and the flashover voltages are decreased with increasing frequency. The reliability of the insulation structure design results was confirmed by the applied voltage withstand test on the dry-type transformer model.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132279757","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 Cable Condition Monitoring Strategy For Safe And Reliable Plant Operation","authors":"T. Toll, C. Sexton, Bryan Mcconkey, G. Harmon","doi":"10.1080/00295450.2022.2072651","DOIUrl":"https://doi.org/10.1080/00295450.2022.2072651","url":null,"abstract":"Electrical cables provide essential functions such as delivery of power or instrumentation signals for most industrial monitoring systems. Most cables installed in plants use polymer insulation materials that can become brittle, crack, or degrade over time from exposure to harsh environmental conditions such as elevated temperature, moisture, vibration, mechanical shock and radiation. Wholesale replacement of cables can be expensive, time consuming and impractical. Therefore, implementing a condition monitoring (CM) strategy to identify and quantify degradation and estimate the remaining useful life (RUL) of the cables can be an effective way of managing aged cables. An overall CM strategy includes several steps to assess the health and manage the aging of cables during the operating life of an industrial facility. These steps include performing As-Found evaluations to determine the current condition of installed cables. These As-Found assessments are performed using a combination of destructive, semi-nondestructive, and/or nondestructive CM tests. Destructive and semi-nondestructive CM testing are performed by removing cable and jacket/insulation polymer samples from service and evaluating the mechanical, thermal, chemical, and electrical properties of the materials to determine their overall condition. Nondestructive CM tests are used to perform in-situ testing to identify and assess the condition of degraded sections of cable insulations as well as to identify potential issues in the electrical circuits including degraded terminations, splices and/or connections. Each of these CM methods provides unique and important information on the overall health and performance of cables and insulation polymers. Moreover, a combination of some or all of these methods can be used to assess the condition of installed plant cables, depending on the cable configuration, insulation materials, and the needs of the plant. Predicting RUL is accomplished by performing laboratory accelerated aging of samples for each representative cable polymer type. The accelerated aging methodology involves exposing the cables to elevated environmental conditions that cause the cable polymers (insulation materials) to age faster than the installed cables. During aging, CM tests are periodically performed to trend changes in the electrical, mechanical, thermal, and chemical properties of the cable and insulation material during aging. The Arrhenius method is then used to normalize the accelerated aging data to the cables' in-service temperatures, and this normalized data is then used to estimate the cable's RUL. The focus of this paper will be to describe an overall strategy for condition monitoring of cables installed in harsh environments using in-situ (i.e. nondestructive) and laboratory (destructive and semi-nondestructive) aging assessment techniques.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126824909","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}