{"title":"Coordination of surge protective devices using the current data from lightning field measurements","authors":"F. Heidler","doi":"10.1002/ETEP.4450060615","DOIUrl":"https://doi.org/10.1002/ETEP.4450060615","url":null,"abstract":"Since about 15 years the electric and magnetic fields radiated by lightning have been measured in the region of Munich/Germany From these measurements the maximum current steepness of positive and negative return strokes to ground were derived. It was found that the positive return strokes contain higher current steepness than the negative ones. In low-voltage power distribution systems the concept of lightning protection zones requires that surge protective devices are installed, whenever an electrical line crosses the boundary between two zones. Because the maximum current steepness ofnegative strokes is lower than for positive strokes, it can be concluded that for the coordination of the surge protective devices only the negative return stroke currents have to be considered.","PeriodicalId":50474,"journal":{"name":"European Transactions on Electrical Power","volume":"1 1","pages":"441-444"},"PeriodicalIF":0.0,"publicationDate":"2007-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ETEP.4450060615","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51091170","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":"Assessment of air-density correction for practical electrode systems","authors":"M. Boutlendj, N. L. Allen","doi":"10.1002/ETEP.4450060406","DOIUrl":"https://doi.org/10.1002/ETEP.4450060406","url":null,"abstract":"A survey is given of available data on the effects of air density upon pre-discharges and sparkover for nonuniform field geometries under a variety of voltage waveshapes of both polarities. Semi-empirical relationships describing the trends of the experimental data are presented. The correction methods set up by the IEC are reviewed and some emphasis has been given to the need to distinguish between the separate influences of pressure and temperature in the overall air-density correction factors. The limits of applicability for density correction are also discussed. Finally, a generalised semi-empirical equation taking into account the main atmospheric variations is proposed. This is shown to offer a good accuracy for the calculation of sparkover voltages over a wider density range than has been hitherto been possible.","PeriodicalId":50474,"journal":{"name":"European Transactions on Electrical Power","volume":"39 1","pages":"267-274"},"PeriodicalIF":0.0,"publicationDate":"2007-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ETEP.4450060406","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51089766","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":"Thermal stressing of power semiconductors in pulse‐controlled inverters by output currents of low fundamental frequency","authors":"H. Gambach","doi":"10.1002/ETEP.4450080203","DOIUrl":"https://doi.org/10.1002/ETEP.4450080203","url":null,"abstract":"The range of fluctuation of the junction temperature of power semiconductors in pulse-controlled inverters rises constantly as the fundamental frequency of the inverter output current falls. As a result, the maximum value of the junction temperature lies with low fundamental frequencies considerably above the mean value that is decisive for high fundamental frequeficie.I. This paper takes the example ofa GTO (gate-turn-off) pulse-controlled inverter to explain two processes for reducing the thermal stressing of the power semiconductors at low fundamental frequencies.","PeriodicalId":50474,"journal":{"name":"European Transactions on Electrical Power","volume":"8 1","pages":"91-96"},"PeriodicalIF":0.0,"publicationDate":"2007-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ETEP.4450080203","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51094871","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 corona phenomenon on hybrid AC/DC transmission lines","authors":"I. Metwally","doi":"10.1002/ETEP.4450080609","DOIUrl":"https://doi.org/10.1002/ETEP.4450080609","url":null,"abstract":"The factors affecting corona phenomenon on hybrid AC/DC transmission lines are investigated using a single-phase AC (50 Hz)/single-pole DC reduced-scale model. The variation of DC corona current with DC voltage follows the same conventional formula for rod-to-plane gaps, where the exponent of conductor height increases with DC voltage, but is slightly affected by interspacing. While the AC corona current is inversely proportional to the conductor height with a power range from 0. 7 to 0.8, it also increases with the decrease in interspacing. A field computation program is used to model both an AC 132-kV double-circuit transmission line and analog hybrid lines. The results reveal that hybrid lines cause higher radio noise but the audible noise is nearly the same as or lower than that for the AC double-circuit lines. The trend of the experimental results is in agreement with the computed number of streamers and electric field profiles.","PeriodicalId":50474,"journal":{"name":"European Transactions on Electrical Power","volume":"8 1","pages":"461-468"},"PeriodicalIF":0.0,"publicationDate":"2007-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ETEP.4450080609","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51098923","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":"Convergence improving minimization technique for a modified fast decoupled load flow","authors":"A. Berizzi, A. Silvestri, D. Zaninelli","doi":"10.1002/ETEP.4450060310","DOIUrl":"https://doi.org/10.1002/ETEP.4450060310","url":null,"abstract":"This paper describes an efficient and reliable algorithm that modifies the Fast Decoupled Load Flow (FDLF) in order to overcome non-convergence troubles in solving strongly stressed power systems. The Hartkopf's algorithm for improving the Newton-Raphson method's convergence features in ill-conditioned cases is taken as a basis. The proposed changes to FDLF consist fundamentally in minimizing the squared power mismatches with a second order interpolation technique. The simple modification makes it possible to establish for sure whether a case of non-convergence is owing to numerical or to physical problems, and lets the operator evaluate the system condition correctly. Several numerical examples show the remarkable behaviour of the algorithm proposed.","PeriodicalId":50474,"journal":{"name":"European Transactions on Electrical Power","volume":"35 1","pages":"201-206"},"PeriodicalIF":0.0,"publicationDate":"2007-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ETEP.4450060310","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51090085","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":"Principal peculiarities of ceramic and composite insulators for overhead EHV/UHV power transmission lines: Electrical characteristics, performance, reliability and application areas","authors":"N. N. Tikhodeev","doi":"10.1002/ETEP.4450060612","DOIUrl":"https://doi.org/10.1002/ETEP.4450060612","url":null,"abstract":"Areas of rational application of cap-and-pin and rod line insulators manufactured of various materials (porcelain, glass and polymers) are discussed in terms of ensuring high reliability and adequate performance of strings on EHV and UHVAC and DC overhead power transmission lines. It is shown that the most critical characteristics of both cap-and-pin and rod units are their quality in terms of annual in-service failure rates and their polluted dielectric strength at long-duration exposure to the operating voltage. Additional features of importance for HVDC lines are high resistivity of the dielectric and good dielectric strength of each individual unit.","PeriodicalId":50474,"journal":{"name":"European Transactions on Electrical Power","volume":"1 1","pages":"419-425"},"PeriodicalIF":0.0,"publicationDate":"2007-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ETEP.4450060612","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51091420","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":"Accelerated ageing tests on composite hollow insulators under DC voltages","authors":"W. Petruseh, K. Week","doi":"10.1002/ETEP.4450060614","DOIUrl":"https://doi.org/10.1002/ETEP.4450060614","url":null,"abstract":"Investigations are reported on two specimen of silicone rubber hollow insulators at a DC voltage of - 1oo kV. Leakage current measurements are performed under natural pollution conditions and with artificial wetting. On the surface ofnaturally polluted insulators energised with DC voltage several types ofsimple microbes were found, which may influence the leakage current performance. It is also shown that accelerated ageing procedures using salt fog for creating surface discharges are not representative for inland sites with a low degree of pollution. Ageing performance of non-ceramic insulators should be checked in general with respect to the UV-strength of the material used. Accelerated ageing tests regarding pollution performance are necessary only if the site conditions will create surface discharges on the non-ceramic material chosen for the insulator. A test procedure, based on the IEC 1 000 h test, with constant discharge activity over a selected duration is proposed for further investigation. There is no advantage regarding creepage distance dimensioning ofnon-ceramic insulators in comparison to porcelain insulators for sites with surface discharges under natural conditions. The use of non-ceramic insulators for areas with very heavy or extreme pollution seems to be questionable.","PeriodicalId":50474,"journal":{"name":"European Transactions on Electrical Power","volume":"6 1","pages":"433-440"},"PeriodicalIF":0.0,"publicationDate":"2007-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ETEP.4450060614","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51091130","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}