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Le magistère de l'UNTD Oksana Toptchy

Oksana Topchy

Departement: electrotechnical

Chair: electrotechnical systems of power supply

Subject of master's thesis:

Analysis the dose of flicker by periodics fluctuations of charge

Research director: Kourenny Edward Grigorievitch

Autobiography

Author's abstract

    Objectives and problems

   Electrosupply networks should be projected so that rapidly variables load would not cause inadmissible fluctuations of voltage. An admissible voltage excursion as frequency is normalised in standards [1, 2] on electromagnetic compatibility. The dose of flicker (DF) is a universal indicator of electromagnetic compatibility. Curves of fluctuations give the exact decision only for periodic changes in the meander form. For periodic fluctuations of other form methods of the account recommended in [1] do not provide coincidence of received results to an estimation of admissibility of fluctuations of voltage on a dose of flicker. It is required to develop a method of calculation of doses of flicker at voltage variations of any form.

    Currency

   In normal conditions in a network of distribution of the electric power there are the fast fluctuations of voltage caused by connection and switching-off of various loadings. Similar loadings lead to occurrence of fluctuations of voltage level repeating in time. In practice these fluctuations try to limit, keeping them in such limits not to create inconvenience for users of electric energy.
   The device consuming the electric power and most sensitive to fluctuations of the voltage level is an incandescent lamp. Because of fluctuations of the voltage level in a lamp there are fluctuations of light exposure which can harm the one who uses electric lighting. Development of scientifically proven methods of calculation of doses of flicker at periodic fluctuations of loading is of great importance.

    Planned practical result

   The dose of flicker is a universal objective indicator of an admissibility of fluctuations. In working electrical networks the dose is measured by the flickermetre, and in designing - settlement by. In GOST 13109-97 the approached methods of account only for special cases of the determined fluctuations of the rectangular and triangular form - besides with essential restrictions of space of times between the next fluctuations are recommended. Development of the general method of estimation without restriction by the form fluctuations is the work purpose.

    Fluctuations and the dose of flicker

   Universal indicator of an admissibility of fluctuations of voltage is the dose of flicker which estimates additional fatigue of the person from the fluctuations of brightness caused by changes of effective values of voltage in a frequency range to 35 Hz.

   Fliker-model [5] includes: :
       - entrance block in which of voltage are allocated fluctuations;
       - the weighing filter modelling a lamp and reaction of sight and a brain of the person on fluctuations of brightness;
       - block of square-law inertial smoothing which models visual sensation, reflecting the fatigue of the person;
       - block of calculation of an indicator of electromagnetic compatibility in which calculate the dose of flicker.

    Method of «partials reactions»

   The method essence « partials reactions» consists that the filter is replaced with equivalent system which consists from n in parallel included inertial links of the first order. This reception allows defining easily “partials” reactions y (t) each link on an input action, and then them to summarize.

    Summary of own results which are available by the moment of end of work on the author's abstract

   At the given stage master's work the analytical decision of a problem about DF has been received at rectangular fluctuations which allow receiving admissible curves of fluctuations with different duty factors.
   Reaction of the weighing filter should be defined by the decision of a differential equation of the fourth order. With that end in view we will apply a method partial reactions according to which the weighing filter it is represented in the form of four in parallel connected inertial links.
   Summation the partial reactions give final expression:

    Eqn26

    After definition of reaction ВФ, it is squared and passed through an inertial link from a time constant 0,3 with, i.e. through block KSI. Dependence dose of flicker on scope and an oscillation frequency has been found. Having substituted in it admissible value of dose of flicker which is equaled to unit, we will find curves of admissible fluctuations of function of frequency (fig. 1). At the big frequencies of fluctuation the work on the person less, than it is less space factor. In these cases use of curves from standards gives considerable overestimate of estimations of electromagnetic compatibility.

Figure 1 - Curves of admissible fluctuations as frequency
    Figure 1 - Curves of admissible fluctuations as frequency

   Thus, the received analytical decision of the problem of dose of flicker by rectangular fluctuations allows improving norms [1, 2] by introduction to these standards of curves from fig. 1.

    Conclusions

   1. Conceptions of ranges and oscillations frequencies in overwhelming majority of cases do not reflect a problem being, therefore the estimation of an admissibility of fluctuations of voltage should be made on a dose of flicker.
   2. Calculation of characteristics of reactions of the filter of flickermetre is expedient make on an offered method of partial reactions.
   3.GOST 13109-97 regarding an estimation of fluctuations of voltage demands specification of areas of applicability of curve fluctuations and perfection of methods of calculation.

    Important remark

   At a writing of the present author's abstract master’s work is not finished yet. Definitive end: December 2009. The full text of work and materials on a theme can be received at the author or supervisor of studies after the named date.


    Literature

    Литература

    1. ГОСТ 13109-97. Межгосударственный стандарт. Электрическая энергия. Совместимость технических средств электромагнитная. Нормы качества электрической энергии в системах электроснабжения общего назначения. – Введ. в Украине с 01.01.2000 [Электронный ресурс]http://epicentre.com.ua/doc8734.htm
    2. CEI/IEC 61000-4-15. Electromagnetic compatibility – Part 4, Section 15: Flickermeter – Functional and design specification. 1997.
    3. Куренный Э.Г., Лютый А.П., Черникова Л.В. Метод парциальных реакций для анализа процессов на выходе линейных фильтров в моделях электромагнитной совместимости. – Электричество, 2006, №10. – С.11-18.
    4. Мельник В.Н., Куренный Э.Г. Оценка влияния колебаний напряжения на электромагнитную совместимость при периодическом изменении напряжения. – Праці Донецького державного технічного університету «Електротехніка і енергетика». – Донецьк, випуск 17, 2000. – с.142-145.[Электронный ресурс] http://masters.donntu.ru/2007/eltf/andrushkevich/library/kolebanie.htm

    5. Кузнецов В.Г., Куренный Э.Г., Лютый А.П. Электромагнитная совместимость. Несимметрия и несинусоидальность напряжения. – Донецк: Норд-Пресс, 2005. – 250 с.
    6. Куренный Э.Г., Цыганкова Н.В. Расчет доз фликера напряжения. Збірник наукових праць, ДонНТУ. Серія "Електротехніка і енергетика", випуск 50.- Донецьк, ДонНТУ,2002.- С. 88-92 [Электронный ресурс]http://masters.donntu.ru/2007/eltf/andrushkevich/library/doza.htm

    7. Куренный Э.Г., Дмитриева Е.Н., Погребняк Н.Н., Черникова Л.В., Цыганкова Н.В. Аналитический метод расчета показателей случайных колебаний напряжения в электрических сетях. - – Праці Донецького державного технічного університету «Електротехніка і енергетика». – Донецьк, випуск 17, 2000.
    8. Цыганкова Н.В. Оценка допустимых колебаний напряжения по размахам и частотам. "Технічна електродинаміка", частина 3, 2002. - С, 17 - 22.
    9. Курінний Е.Г., Дмітрієва О.М., Топчій В.О. Дози флікеру при періодичних коливаннях напруги.
    10. Mirra C., Sani G.Il femomeno del flicker. Analizi delle sue caracteristiche. Techniche di misura e medodi dilimitazione.-L'Elettrotecnica. - 1987.
    11. Шидловский А.К., Куренный Э.Г. Введение в статистическую динамику систем электроснабжения. Ц Киев: Наукова думка,1984. Ц 272 с.
    12. Ермилов А.А. Основы электроснабжения промышленных предприятий. - М.: Энергоатомиздат, 1983. - 208 с.
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