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Endurance Ibaraboke Okuru. AC breaker with forced switching off [Электронный ресурс]: магистерская диссертация: 13.04.02 / Endurance Ibaraboke Okuru; Peter the Great St. Petersburg Polytechnic University, Institute of Energy and Transport Systems ; supervisor V. Y. Frolov. — Электрон. текстовые дан. (1 файл : 2,39 Мб). — Санкт-Петербург, 2017. — Загл. с титул. экрана. — Текст на англ. яз. — Свободный доступ из сети Интернет (чтение, печать). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/v17-4762.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/v17-4762>.

Record create date: 10/26/2017

Subject: Выключатели; Токи короткого замыкания; Релейная защита; breaker; short circuit; current interruption; hybrid breaker; protective device

UDC: 621.316.542(043.3); 621.316.925.1(043.3); 621.3.064.1(043.3)

Collections: Выпускные квалификационные работы; Общая коллекция

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One of the essential prerequisites of protective devices is speed. A protective device should be capable of clearing a fault within the minimalworking time to avoid damage to power system equipment. Long term exposure to fault currents and switching transients are hazardous to the power system equipment and can shorten their running lifetime. Conventional circuit breakers switch only at the point of zero crossing, this causes the system on occasion, experience high short circuit currents for a period of time before this current is switched off by the breaker. A way of decreasing these gradually aggregating effects is the limitation of the short circuit current burden on the power system components by the breaker and a very expeditious breaker operation to switch off this current. A hybrid breaker is the ideal option for implementing these recommendations and solutions. The hybrid breaker givesquick fault current interruption of insignificant losses in steady-state operation through a mix of mechanical fast disconnectors, semiconductors and varistor. It is appropriatefordiverselevels of system voltage and depends on the distinct project requirements. These ultra-fast hybrid breakers are as of now beingimproved on for HVDC networks. This report focuses on its application to 11kv AC system. A feature of this design is its small operating time (. It consists of three identical blocks, one block for each phase and works in the two stages. Each such unit is a two-stage device, the first stage consists of vacuum arc interrupter connected in series with a powerful field-effect transistor. The second stage of the unit consists of two thyristor switches connected in parallel. The vacuum interrupter chamber has a fast electrodynamic drive. A necessary part of this unit is a counter-bank capacitor, providing an alternating current transition to a zero value notwithstanding the current phase or direction.

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