Shadowing Practice: 17E058 - Back to Back Stations - Learn English Speaking with Video

Ders oluşturuluyor...
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Hello everyone, I am Monika.
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I am here to present back -to -back stations.
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Let's see.
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What is back -to -back?
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Generally, in electronics and power electronics, if two bipolar components are connected in series with opposite polarity, then this pair is known as back -to -back system.
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As same as in electrical, rectifiers and inverters are identical
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and connected in series is known as back -to -back system from this diagram here rectifier
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and the inverter are connected in series via a hvdc link
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and it is also a hvdc back -to -back link a back -to -back hvdc link the hvdc system
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which transfers energy between two ac buses at the same location is called as back -to -back system
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or an hvdc coupling system in other words the converters
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and rectifiers are installed and operates on high voltage DC in the same stations.
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Hence there is no DC transmission line.
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So it reduces the overall conversion cost and improve the reliability of the DC system.
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Such type of system is designed for bipolar operation.
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This picture shows the bipolar link of a back -to -back link.
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A bipolar link has two conductors.
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One is positive and the other one is negative.
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This link has two converter stations at each end.
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The midpoint of the converter station is connected to the air through the electrodes.
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Next, we are going to see about the construction of back -to -back HPDC link.
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The main components are converter station, converter unit, converter vaults, converter transformer,
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filters, high frequency filter, reactive power source, smoothening reactors and then system port.
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What do you mean by converter walls?
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There are two types of converter walls.
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One is the sending end converter and then receiving end converter.
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The sending end converter act as a rectifier which converts AC into DC.
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The receiving end converter act as a inverter which converts DC into AC.
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What are converter transformers?
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These are transformers
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which are used before the rectification of ac in the hvdc system filters filters may be ac
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or dc what is the use of high frequency filters these
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are provided to suppress the high frequency currents what do you mean by smoothening reactors smoothening reactors are those
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which is used on the dc side to smoothen the dc current as well as the production purposes
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This shows the simple block diagram of back -to -back HPDC link.
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From the system 1, AC current is converted into DC by means of rectifier
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and current DC is supplied via DC link
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and it is converted back again to AC by means of inverter and then distributed to the different grids.
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It shows the simple block diagram.
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Working principle of back -to -back link.
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Two independent neighboring transmission systems with incompatible electrical parameters such as frequency
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or voltage level or short -circuit power level are connected via a DC link.
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The basic principle operation of HPDC linking system is based on the conversion of AC to DC
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and vice versa by means of converter volts power from two
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or more system is first converted into dc by means of power rectifier system
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and then summed up after summing of the resultant power is
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again converted into ac with the help of power inverter
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and then supplied to different grids the process involved in here is simple only by theoretical
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but in practical it is very much complex as it involves high voltages
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and power semiconductor devices what are the needs for back -to -back stations we all know
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that high voltage ac is used to transmit the electrical power for reducing power transmission losses
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in a transmission system different grids are interconnected but sometime it might happen
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that one or more grids or power systems may not be in synchronization with other grids
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or there exist a weak link between different power systems due
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to various factors to overcome these problems hvdc back -to -back system is created it also can be used
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when two asynchronous ac system need to be interconnected for a bulk power transmission
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and also for the stabilization processes these are the some examples of back -to -back stations mcnell hvdc back -to -back station,
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HVDC back -to -back link commissioned between India and Bangladesh, Chandrapur HVDC back -to -back station, Vaisak back -to -back station, Windyashal back -to -back station.
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We will see them one by one in the following slides.
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McNeil HVDC Back -to -Back Station A back -to -back station
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is a series of HVDC interconnectors between the unsynchronized eastern and western AC systems of United States and Canada.
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It connects the power grids of Canadian provinces at Alberta and Saskatchewan.
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The station was built by Geck -Alstom,
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was commissioned in 1989, with the power capacity about 150 megawatt at a DC voltage of 42 kilovolt.
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This picture shows the back -to -back station at Alberta.
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Mechanical station was notable for operating with low short -circuit ratio.
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What do you mean by short -circuit ratio?
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Short -circuit ratio is a measure of how strong or weak the connected AC system is.
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Most of the HVDC schemes uses line commutated converters with SCR about 3,
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but McNeill's scheme was designed to operate with an effective SCR which is even less than 1 .0 on the SASCAT7 side.
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So hence it was the only SCR with the lowest value
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ever achieved with the line commutated hvdc converter it is also
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considered as the first hvdc station to use three phase four winding converter transformer the transformer
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which are connected at the 138 glow volt at alberta side
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and 230 glow volt on the saskatchi one side the number of poles used in this link is about only one Next,
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we are going to see about Indo -Bangladesh link, a SVDC back -to -back link commissioned between India and Bangladesh.
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This Indo -Bangladesh link was commissioned by Siemens.
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Here, two back -to -back links are installed.
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The block one is in operation since 2013 with a capacity of 500 megawatts.
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Siemens recently announced that in June 2020, it fully commissioned the second block of hvdc back -to -back
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line in barhamara at bangladesh to connect the electricity supply network to india
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and bangladesh with the transmission capacity of 500 megawatts hence a total capacity is up to 1000 megawatt
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which is the highest reliable power capacity in bangladesh Siemens is a world leader in HVDC technology,
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which has installed more than 55 projects worldwide with an overall capacity of 94 GW.
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This picture shows the back -to -back stations at Biramara at Bangladesh.
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This is the map which shows the back -to -back HVDC link between India and Bangladesh.
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Here, from Biramara, at the western border of Bangladesh,
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a 230 kV grid of the country will be connected via substation and OH lines to India's 400 kV grid,
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which is located at Baharampur.
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Next, we are going to see about Chandrapur back -to -back HVDC station.
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It is a back -to -back HVDC connection between western and southern regions in India located close to the city of Chandrapur.
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Its main purpose is to export power from the Chandrapur Super Thermal Power Station to the southern regions of Indian National Grid.
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This picture shows the power station at Chandrapur.
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It was owned by Power Grid Corporation of India and the installer for the substation is Gek Alstom and commissioned in 1997.
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7 with a power capacity of 500 megawatts at a dc
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voltage of 205 kilo volt at each pole next we are
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going to see about why is a back -to -back hvdc
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station why is a back -to -back hvdc station is a back -to -back hvdc station connection between the eastern
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and southern regions in india located close to the city of Viswagapatnam in the state of Andhra Pradesh.
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It was owned by Power Grid Corporation of India.
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It has two substations namely VISAG -1
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and VISAG -2 commissioned in 1999 by Alstom
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and the latter in 2005 by ABB
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which has a power capacity of 500 megawatts
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and a DC voltage of 205 kilovolt at ysac 1 and 176 kilovolt at ysac 2.
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It consists of two independent poles.
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The station is no longer required for its original purpose of linking eastern and southern grids,
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although it can be still used as an embedded power flow device to help control power flow within the AC system.
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Next, we can see recent developments.
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Power Grid Corporation of India has chosen Siemens to upgrade India's oldest HVDC link,
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which is the India's oldest HPDC link.
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Any guess, Vintiachal back -to -back HPDC link is the India's oldest link.
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And Siemens has been chosen by Power Grid of India to modernize it.
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Next, we can see some of the advantages of back -to -back HPDC link.
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Power can be upgraded to desired frequency then two asynchronous systems can be joined successfully without loss of stability
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stability of the system is increased as well as power flow can be maintained within the limits
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more active power can be added where the ac system is
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already at the limit of short circuit capability then it also
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helps in the stabilization of weak ac signals weak ac links thank you

Bu dersin kelimeleri ve konuşma notları

Bu konuşma dersi “17E058 - Back to Back Stations” videosuna dayanıyor. En çok tekrarlanan kelimeler: link, station, hvdc, converter, grid. Bu videoda gölgeleme çalışması için 119 cümle ve 1512 kelime var. Konuşma bölümü 11:21 sürüyor. Konuşmacı dakikada yaklaşık 133 kelimelik dengeli bir hızla konuşuyor; gölgeleme için rahat bir tempo. Kelimelerin yalnızca %76’i İngilizcede en sık kullanılan 3.000 kelime arasında, bu yüzden kelime dağarcığı zorlayıcı.

Bu videodaki önemli kelimeler

Videodan öğrenmeye değer 15 kelime, telaffuzu ve anlamıyla:

KelimeTelaffuzAnlam
grid isim/ɡɹɪd/şebeke
voltage isim/ˈvəʊltɪd͡ʒ/gerilim
convert fiil/kənˈvɝt/dönüştürmek
frequency isim/ˈfɹiːkwənsi/frekans
filter isim/ˈfɪltɚ/filtre
hence zarf/ˈhɛns/itibaren
ratio isim/ˈɹeɪ.ʃoʊ/oran
pole isim/pəʊl/kutup
locate fiil/ˈloʊˌkeɪt/yerleştirmek
diagram isim/ˈdaɪ.ə.ɡɹæm/şema
reactor isim/ɹiˈæktɚ/reaktör
principle isim/ˈpɹɪn.sɪ.pəl/prensip, ilke
component isim/kəmˈpoʊ.nənt/parça, bileşen
stability isim/stəˈbɪlɪti/stabilite
conversion isim/kənˈvɝʒən/çevirim, dönüşüm

Bu videodaki dil bilgisi

Konuşmacının en çok kullandığı yapılar, videodaki sözcüklerin aynısıyla:

YapıVideoda
Edilgen yapı be + fiilin üçüncü hâli — kimin yaptığı değil, ne olduğu önemliare connected · is known · is called
Present perfect have/has + fiilin üçüncü hâli — geçmişte olan ama şimdi de önemli olan bir eylemhas installed · has chosen · has been chosen

Dikkat edilecek telaffuzlar

  • “th” sesleri: theoretical /ˌθi.əˈɹɛt.ɪ.kəl/, smoothen /ˈsmuːðən/
  • “sh” ve “zh” sesleri: transmission /tɹænsˈmɪʃən/, ratio /ˈɹeɪ.ʃoʊ/, conversion /kənˈvɝʒən/, substation /sʌbˈsteɪʃən/, stabilization /ˌsteɪ.bəl.ɪzˈeɪ.ʃən/
  • Uzun kelimeler — vurguyu doğru yere koyun: electrical /ɪˈlɛktɹɪkəl/, stability /stəˈbɪlɪti/, electronics /ɪˌlɛkˈtɹɑ.nɪks/, successfully /səkˈsɛs.fə.li/, electricity /ɪˌlɛkˈtɹɪsɪti/

Türkçe konuşanların zorlandığı sesler:

  • Kelime başındaki ünsüz kümesi — araya ünlü eklemeyin: grid /ɡɹɪd/, transmission /tɹænsˈmɪʃən/, frequency /ˈfɹiːkwənsi/, principle /ˈpɹɪn.sɪ.pəl/, stability /stəˈbɪlɪti/
  • /æ/ — “e”den daha açık: transmission /tɹænsˈmɪʃən/, diagram /ˈdaɪ.ə.ɡɹæm/, reactor /ɹiˈæktɚ/, practical /ˈpɹæk.tɪ.kəl/, mechanical /məˈkænəkəl/

Bu videoyla nasıl çalışılır

  1. Videonun tamamını konuşmadan bir kez dinleyin ve bilmediğiniz kelimeleri not edin.
  2. Normal hızda cümle cümle tekrar edin; ritminiz konuşmacıyla aynı olana kadar her cümleyi yineleyin.
  3. Kendinizi kaydedin ve orijinaliyle karşılaştırın; grid, voltage, convert gibi kelimelere özellikle dikkat edin.

Gölgeleme Tekniği Nedir?

Gölgeleme, başlangıçta profesyonel tercüman eğitimi için geliştirilen ve çok dilli Dr. Alexander Arguelles tarafından popüler hale getirilen, bilim destekli bir dil öğrenme tekniğidir. Yöntem basit ama güçlüdür: ana dili İngilizce olan bir sesi dinler ve hemen yüksek sesle tekrar edersiniz — konuşmacıyı 1-2 saniye gecikmeyle takip eden bir gölge gibi. Pasif dinleme veya dilbilgisi alıştırmalarının aksine, gölgeleme beyninizi ve ağız kaslarınızı gerçek konuşma kalıplarını eşzamanlı olarak işlemeye ve yeniden üretmeye zorlar. Araştırmalar, telaffuz doğruluğu, tonlama, ritim, bağlı konuşma, dinleme anlama ve konuşma akıcılığını önemli ölçüde geliştirdiğini göstermektedir — bu da onu IELTS Konuşma hazırlığı ve gerçek dünya İngilizce iletişimi için en etkili yöntemlerden biri yapar.

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