http://ea.donntu.ru/handle/123456789/5729 2026-04-19T23:50:35Z http://ea.donntu.ru/handle/123456789/24984 Title: Защита от замыканий на землю в сетях с кабелями с изоляцией из сшитого полиэтилена Authors: Гребченко, Николай Васильевич; Кожухарь, А.В.; Демченко, О.В.; Grebchenko, N.V.; Kozhukhar, A.V.; Demchenko, O.V. Abstract: Предложена новая последовательность взаимодействия защиты от замыканий на землю и средств диагностирования. Для повышения чувствительности защиты и средств диагностирования в трансформаторах тока нулевой последовательности используется дополнительная магнитодвижущая сила, создаваемая источником напряжения нулевой последовательности или источником рабочих фазных и линейных напряжений. Направленность действия защиты обеспечивается путем контроля направления мощности нулевой последовательности, а также за счет обмена информацией между комплектами защит с двух сторон линии. Description: The new sequence of interaction of protection against short circuits on the earth and diagnostics tools for electro supply systems in which cables with isolation from the sewed polyethylene are used is offered. For increase of sensitivity of protection and diagnostics tools in transformers of a current of zero sequence the force created by a source of pressure of zero sequence or a source of working phase and linear pressure is used additional m.m.s. In addition the operation current decreases thanks to indemnification of own capacitor current of a protected line. Selectivity of action of protection is provided at the expense of its orientation by the control of a direction of capacity of zero sequence. On consistently included lines for maintenance of absolute selectivity information interchange between complete sets of protection from two parties of a line is realized on a communication channel. Electric equipment diagnosing is carried out without its switching-off once a day. If necessary the system can give the information on a concrete phase in which there was a local defect of isolation. It is offered to carry out selective increase of sensitivity of diagnostics tools to an active component of a vector of a current through isolation and separately - to a jet component of this curren. 2014-01-01T00:00:00Z http://ea.donntu.ru/handle/123456789/24983 Title: Модернизированное искробезопасное коммутационное устройство с блоками ручного, дистанционного и сенсорного управления Authors: Солёная, Оксана Ярославовна; Solenaya, O.Ya. Abstract: В статье обоснована опасность возникновения источников зажигания пожаровзрывоопасных сред в современных защитно-коммутационных аппаратах для низковольтных электрических сетей при их эксплуатации, а также выявлены недостатки разработок в области искробезопасных коммутационных устройств. Предложены схемные решения искробезопасного коммутационного устройства с блоками ручного, дистанционного и сенсорного управления, проведены испытания изготовленного опытного образца. Description: The paper considers the problem of the sources of ignition in modern protective switching units for low-voltage electrical networks in the process of their operation. Besides we have found out some drawbacks in the field of spark-safe switching units design. 2013-01-01T00:00:00Z http://ea.donntu.ru/handle/123456789/24982 Title: Сучасні підходи до технічного обслуговування устаткування електричних систем Authors: Полковніченко, Дмитро Вікторович; Polkovnichenko, D.V. Abstract: Ефективність роботи електричних систем багато в чому залежить від надійної роботи електричного устаткування, яка в свою чергу визначається стратегією його обслуговування і ремонтів. У даній статті розглянуті сучасні підходи до впровадження системи обслуговування електроустаткування електричних систем за фактичним станом, яка дозволить зменшити експлуатаційні витрати та збільшити надійність цих систем в цілому. Description: The most important problem of the modern industry is a question of the ensuring the maximum production effect (the ensuring the maximum profit). The solution to this problem in electric systems much depends on reliability of the work and rationality of the system of the technical maintenance and repairs of the electric equipment. At present for support of the electric equipment in runnable state system planned-preventive repair is used. However in modern conditions the efficiency of the measures, which are specified for these systems, is very low. So at present the most efficient there is system of the servicing the equipment according to the real technical state. The system of maintenance according to real state requires the additional expenses for introduction of the systems of the diagnostics and prognostication of the equipment state. But on the practice these expenses are quickly compensates and brings additional profit. The purpose of this article is an analysis of the modern approaches of introduction and using of the technical maintenance according to real state of the equipment on electric systems. For each element, the node, the aggregate must be selected its strategy with provision for their role in ensuring the factors of efficiency of equipment exploitation with use of the economic and mathematical models. In conformity with concept of the system of the maintenance according real state for decision making about need of the reconstruction and repair it is necessary to have operative information on technical condition of the nodes or equipment as a whole. Therefore, one of the main tasks is to select the method of diagnostics for receipt of the information on the equipment technical state with a high validity. Diagnostics of the technical state and prognostication of reliability can be done at different stages of development and use of electrical equipment: during the design, production and exploitation. At the last years approach is offered, which has got the name "multivariable diagnostics". According to the concept of multivariable diagnostics the optimal set of diagnostic methods is defined according to the type of electrical equipment. Use of system of the maintenance according to real state allows also to check the quality of the repair execution and erection-adjustment works. The conducted analysis has shown that introduction of the system of the maintenance according to real states of electric systems electric equipment will allow to reduce the expenses on the maintenance and raise reliability of the functioning the equipment. But it is necessary to carry out the following work: improve the methods of diagnostics and prognostication of the electrical equipment technical state; devise a combined technical means of diagnostics and prognostication of the electric equipment technical state; improve the qualification and professionalism of the staff of electrical systems; create on the enterprises of electric power engineering of specialized laboratories whose task is to carry out the diagnostics and prognostication of the electrical equipment technical state. 2013-01-01T00:00:00Z http://ea.donntu.ru/handle/123456789/24981 Title: Оцінювання електромагнітної сумісності за несинусоїдальності напруги у діючих мережах Authors: Дмитрієва, Олена Миколаївна; Ларіна, Інна Іванівна; Лютий, Олександр Павлович; Larina, I.I.; Lyuty, A.P.; Dmitrieva, E.N. Abstract: Розглядається задача оцінювання ЕМС при неперіодичних спотвореннях синусоїдальної напруги. Показується невизначеність понять синусоїдальної і несинусоїдальної компонент. Пропонуються засоби усунення невизначеності: шляхом виділення синусоїдальної складової кореляційної функції або попереднього осереднення кривої напруги. Приводиться приклад оцінювання ЕМС конденсаторної установки. Description: Voltage unsinusoidality causes the additional losses of active power and reduction of electrical equipment service life. For the estimation of these effects it is necessary to select two components from voltage oscillogram: sinusoidal (SC) with frequency 50 Hz and nonsinusoidal (NSC). For periodic processes this task is decided unequivocally: by decomposition in the Fourier series. However in operating electric networks the processes are unperiodical. The notion “harmonic” is absent for them. Therefore the estimation of EMC by “harmonics” and “interharmonics” is mathematically incorrect, and task of separation the components is theoretically indefinite. The methods of elimination of uncertainty are considered in the article, and the estimation of EMS of the condenser setting is as an example given. The spectral density of voltage is used in the first method of SC separation. Such possibility is conditioned that in a neighbourhood of frequency 50 Hz the very narrow impulse is observed on the density graphic. It is considered the spectral density of SC. The spectral density of NSC is determined as a difference of densities. In the second method the SK is separated by a narrow-band filter on frequency 50 Hz with subsequent compensation of phase shift. In the absence of low-frequency distortions it is suggested to use continuous averaging of voltage on an interval no more than 0,01 s without a phase shift. Reduction of process ordinates after averaging is compensated by their division into the amplitude-phase characteristic value of averaging window at frequency 50 Hz. NSC is determined by subtraction of obtained SC from an initial process. The condenser setting is designed as three series connected links: proportional, forced and oscillatory. EMC is estimated by effective current, which must not exceed 130 % from rated. The effective current and its components are calculated on the appropriate spectral densities either on SC or NSC of voltage. In last case it is recommended to use the method of partial reactions, where the model of condenser setting is offered by two inparallel inertia links of the first order. An example of EMC estimation of the condenser setting during work of arc steelmaking furnace is given. 2014-01-01T00:00:00Z