تخمین بار برف و یخ جهت طراحی خطوط انتقال نیرو فشار قوی با دوره‌های بازگشت چند ساله (مطالعه موردی: ارتفاعات غربی مازندران)

نوع مقاله : علمی -پژوهشی

نویسندگان

1 گروه جغرافیا، دانشگاه آزاد اسلامی واحد نور، نور، ایران

2 گروه جغرافیای طبیعی، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران

چکیده

یکی از مشکلات شرکت برق منطقه‌ای در مناطق سردسیر، یخ‌زدگی و نشست برف بر روی سیم‌های خطوط انتقال نیرو می‌باشد. پهنه‌بندی آب و هوایی و ارائه شرایط بارگذاری متناسب با منطقه جهت طراحی مکانیکی خطوط حائز اهمیت بوده و انتخاب صحیح این شرایط به‌لحاظ فنی و اقتصادی تاثیر بسزایی در طراحی پروژه خواهد داشت. نقشه بار برف و یخ که در گذشته توسط وزارت نیرو تدوین گردیده، کارایی و نوآوری لازم را نداشته و یا اینکه برای بسیاری از مناطق توسعه یافته جدید شهری و روستایی بازنگری نشده است در این تحقیق پارامتر آماری ضخامت یخ با دوره‌های بازگشت چند ساله، که ازجمله بارهای موثر در بارگذاری دکل انتقال نیرو هستند با استفاده از داده‌های هواشناسی (سال 2010 تا 2018 میلادی) سه ایستگاه کوهستانی بلده، کجور و سیاه بیشه در غرب مازندران مورد ارزیابی قرار گرفتند و در نهایت مقادیر اسمی جدید با دوره بازگشت‌های مختلف پیشنهاد گردیده است. نتایج نشان داد که برای طراحی خطوط انتقال نیرو با دوره بازگشت کمتر از 50 سال، منطقه بلده و کجور جزو مناطق سنگین و با دوره بازگشت بیشتر از 50 سال جزو مناطق فوق سنگین و منطقه کجور با دوره بازگشت 50 تا 100 ساله جزو مناطق متوسط و دوره بازگشت بیشتر از 100 سال جزو مناطق سنگین (مطابق با آیین نامه مشانیر) می‌باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Estimation of snow and ice accretion for the design of high-pressure transmission lines with multi-year return periods (case study: western highlands of Mazandaran)

نویسندگان [English]

  • gholamali Ahmadi 1
  • Gholamreza Janbaz ghobadi 1
  • sadroddin motevalli 1
  • shahriar khaledi 2
1 Department of Geography, Islamic Azad University- Nur Branch, Nur, Iran
2 Department of Physical Geography, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran
چکیده [English]

IntroductionOne of the problems of the power companies in cold areas is freezing and snowfall on the transmission lines. Therefore climatic zoning of the Mazandaran province and the load conditions in accordance with requirements of the region are important for the mechanical design of the transmission lines. The correct selection of these conditions have a significant technical and economic impact on designing the project. One of the problems of a regional power company in cold, frosty and snowy areas is the wiring and shielding of power lines. Snow and ice load maps developed by the Ministry of Energy do not have the necessary efficiency and innovation anymore and were not reviewed for many newly developed urban and rural areas. Iran is divided into four regions of light, medium, heavy and super heavy in terms of weather conditions and for each of these regions, the four main and primary variables of loading, namely normal wind speed, maximum wind speed, normal ice thickness and maximum ice thickness are provided.Materials and MethodsThe purpose of this study is applied and the nature and method of research is descriptive-analytical. In this study, the parameter of ice thickness with multi-year return periods, which is one of the effective loads in the loading of the power transmission lines, was evaluated using the weather data (2010 to 2018), at three mountain stations of Baladeh, Kajur and Siah Bisheh in western Mazandaran. Meteorological information is measured hourly at meteorological stations, After collecting and correcting the meteorological data, in the Excel environment and in the final worksheet, the program is written to calculate the daily, monthly, and annual ice thicknesses and to calculate the statistical parameters at a height of 35 meter (mean height of the cables). Using the Smada software, the relevant histograms are plotted.Results and Discussion Eventually, new nominal values were recommended with different return periods. The results showed that in the design of transmission lines with a return period of less than 50 years, Baladeh and Kojur regions are among the heavy areas. With a return period of more than 50 years these points are considered as super-heavy. With the return period of 50 to 100 years, the Kojur area is an intermediate region and a heavy region with the return period of>100 years (in accordance with the Ministerial code also known as Mashanir Code). Therefore calculated values of snow and ice loads for 10 m (less than 66 kW) and 35 m (above 220 kW) elevations were not significant, Based on the results, it is suggested that with the establishment of automatic weather stations in the area and field and laboratory studies, more detailed results will be obtained in future studies.ConclusionIn this research, the ice thickness statistical parameters with multi-year return periods were evaluated, using meteorological data and simulation methods. The meteorological data was provided by Mountain Engineering Laboratory and Research Institute. Finally new nominal values were suggested after comparing them with various return periods. In the case of Baladeh, calculated values of snow load and ice for a height of 35 meters, with different return periods from 50 years onwards, the maximum amount of ice exceeds the nominal value (40) and was likely to cause damage to transmission lines. Therefore, for the design of power lines with a return period of less than 50 years, Baladeh region is one of the heavy areas and with a return period of more than 50 years, it is one of the super heavy areas.For the Siahbisheh area, the amount of snow and ice for the 50 to 100-year return period is moderate, and for return periods greater than 100 years, the heavy areas are less than the nominal average value defined in the Ministerial code(Mashanir). In the Kojour area, which according to Mashanir is a superheavey region, for return periods from 50 years onwards the maximum amount of ice thickness exceeds the Mashanir code. Therefore the probability that it could damage the transmission lines is greater than the nominal value (40). Hence, for the design of power lines with a return period of less than 50 years, the Kojour region is a heavy area and with a return period of more than 50 years, it is a heavy area.

کلیدواژه‌ها [English]

  • Meteorological parameters
  • Snow and ice load
  • Electricity transmission lines
  • West of Mazandaran
-براتی، غ.، احمدی، م.، میرزایی، ا. و بیتار، م.، 1395. ترازیابی زبانه‌های پرفشار سیبری هنگاه رخداد سرماهای بحرانی در ایران مرکزی، نشریه پژوهش‌های دانش زمین، سال هفتم، شماره 26، ص 122-124.
-شرکت سهامی خدمات مهندسی برق (مشانیر)، 1378. نقشه‌های پهنه‌بندی مناطق چهارگانه آب و هوایی کشور، وزارت نیرو: دپارتمان تحقیقات و استانداردها.
-شرکت سهامی خدمات مهندسی برق (مشانیر)، 1377. آیین‌نامه و استاندارد بارگذاری برج‌های انتقال نیرو، وزارت نیرو: استاندارد جامع مهندسی و طراحی خطوط انتقال نیرو.
-قلیچی، ف.، درساره، م. و معانی، ع.، 1390. شناسایی تجهیزات بحرانی شبکه‌های توزیع از نظر قابلیت اطمینان، نشریه هوش مصنوعی و ابزار دقیق، شماره 26(2)، ص 4-5.
-میر شریفی، ا.، 1385. تحلیل آماری متغیرهای بارگذاری در طراحی دکل‌های انتقال نیروی ایران، نشریه دانشکده فنی، شماره 40 (5)، ص713-722.
-نوحی، ا.، 1391. مبانی هواشناسی و اقلیم شناسی، تهران، انتشارات آب و هوا، 396 ص.
-یوسفی، ی.، 1395. تغییرپذیری بارش و دوره‌های تر و خشک در بخش‌های جنوبی دریای خزر، پژوهش‌های دانش زمین، سال هفتم، شماره 25، ص 16-30.
-Bonanno, R., Lacavallan, M. and Marcacclp, P., 2017. Weather Forecast and monitoring system of wet snow sleeve on overhead power lines in Italy, World Energy and Meteorology Council, 28 p.
-Ducloux, H. and Nygaard, B.E., 2014. 50-year return-period wet-snow load estimation based on weather station data for overhead line design in France, Natural Hazards and Earth System Sciences, v. 14(1), p. 3031-3041.
-Gumbel, E.J., 2004. Statistics of Extremes, Dover Publications, 375 p.
-Lehtonen, I., Hoppula, P. and Gregow, H., 2014. Modelling crown snow loads in Finland: a comparison of two methods, Silva Fennica, v. 48(3), p. 1120-1139.
-JilinCai, Q., Minjian, C. and Bin, Y., 2019. A novel importance sampling method of power system reliability assessment considering multi-state units and correlation between wind speed and load, International Journal of Electrical Power & Energy Systems, v. 109(3), p. 217-226.
-Nygaard, B.E., Ágústsson, H. and Somfalvi-Toth, K., 2013. Modeling wet-snow accretion on power lines: Improvements to previous methods using 50 years of observations, Journal of Applied Meteorology and Climatology, v. 52(1), p. 2189-2203.
-Nygaard, B.E. and AmbjørnSeierstad, I., 2014. A new snow and ice load map for mechanical design of power lines in Great Britain, Cold Regions Science and Technology, v. 108(2), p. 28-35.
-Palutikof, J.P., Holt, T., Brabson, B.B. and Lister, D.H., 2000. Methods to Calculate Extremes inClimate Change Studies(1), Climate Research Unit, University of East anglia, Norwich NR47 TJ, UKT, Department of Physics, Indiana University, Bloomington, Indiana 47405,U.S.A.
-Rantaab, J., Polojärviab, A. and Tuhkuriab, J., 2017. The statistical analysis of peak ice loads in a simulated ice-structure interaction process, Cold Regions Science and Technology, v. 133, p. 46-55.
-Xiang-junZeng, X., longLuo, J. and Ting-tingXiong, H., 2012. A novel thickness detection method of ice covering on overhead transmission line, Journal of Applied Meteorology and Climatology, v. 14(5), p. 1349-1354.
-Wang, W. and Peng, W., 2019. Study on sustainable development of power transmission system under ice disaster based on a new security early warning model, Journal of Cleaner Production, v. 228(5), p. 175-184.
-Zarnani, A. and Musilek, P., 2012. Learning to predict ice accretion on electric power lines, Engineering Applications of Artificial Intelligence, v. 25(3), p. 609-617.
-Nygaard, B.E. and Carlshem, L., 2019. Development of a 50-years return value ice load map for Sweden, Int.workshop on Atmospheric Icing of structures, Reykjavik, p. 1-5.
-Solangi, A.R., 2018. Icing Effect on Power Lines and Anti-icing and De-icing Methods, Master’s Thesis in Technology and safety in High North, The ARCTIC UNIVERSITY of NoRWAY, p. 60-65.