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الموضوع: الحماية الترددية

  1. #1
    Junior Engineer
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    الحماية الترددية

    ارجو الافادة في الحماية او الوقاية الترددية في شبكات التوتر المتوسط

  2. #2
    Consultant Engineer الصورة الرمزية أسامة حسن البلخي
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    Sep 2014
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    رد: الحماية الترددية

    :Principle of Over frequency protection
    Normally, Generator is an energy conversion device, which converts mechanical energy into electrical energy and the mechanical energy is given by the steam turbine or diesel engine or gas turbine etc. here the input fuel may be changed but the mechanical energy is given to the alternator/generator by the manner of rotation (revolution). The revolution is directly proportional to the frequency of the alternator/generator. Under Normal condition the frequency is stable around 50Hz or 60Hz. The turbo-generator rotates at rated speed under normal condition. During abnormal condition, increasing the speed in the turbine leads to elevated frequency in the generator. The machine operated at higher speeds at which the rotor material no longer contain the centrifugal forces imposed on them resulting in serious
    damage to the turbine-generator set


    Over frequency relay ANSI code: 81O – Over FrequencyRelays acted
    • Flag operation at 81O – Over Frequenc
    • 86 M grid master trip acted for stage-1, tripping of 110kV grid breaker
    • 86 M Gen Mater trip acted for stage -2 if the speed of the turbine is not controlled.
    • Indication at Annunciation Panel.

    الملفات المرفقة الملفات المرفقة
    لاإله إلا الله محمد رسول الله

  3. #3
    Consultant Engineer الصورة الرمزية أسامة حسن البلخي
    تاريخ التسجيل
    Sep 2014
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    رد: الحماية الترددية

    Protective relay

    From Wikipedia, the free encyclopedia


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    Electromechanical protective relays at a hydroelectric generating plant. The relays are in round glass cases. The rectangular devices are test connection blocks, used for testing and isolation of instrument transformer circuits.

    In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is detected.[1]:4 The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, over-voltage, reverse power flow, over-frequency, and under-frequency.[2]
    Microprocessor-based digital protection relays now emulate the original devices, as well as providing types of protection and supervision impractical with electromechanical relays. Electromechanical relays provide only rudimentary indication of the location and origin of a fault. [3] In many cases a single microprocessor relay provides functions that would take two or more electromechanical devices. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays.[4] However, due to their very long life span, tens of thousands of these "silent sentinels"[5] are still protecting transmission lines and electrical apparatus all over the world. Important transmission lines and generators have cubicles dedicated to protection, with many individual electromechanical devices, or one or two microprocessor relays.
    The theory and application of these protective devices is an important part of the education of a power engineer who specializes in power system protection. The need to act quickly to protect circuits and equipment as well as the general public often requires protective relays to respond and trip a breaker within a few thousandths of a second. In some instances these clearance times are prescribed in legislation or operating rules.[6] A maintenance or testing program is used to determine the performance and availability of protection systems.[7]
    Based on the end application and applicable legislation, various standards such as ANSI C37.90, IEC255-4, IEC60255-3, and IAC govern the response time of the relay to the fault conditions that may occur.[8]








    وظيفة الحمايات الترددية في الشبكة هو الحفاظ على التردد في الشبكة بقيمة 50 HZ - فإذا زاد الاستهلاك على قيمة الانتاج بأكثر من 5 % .. ساافعل الخمايات الترددية وتفصل أحمال الأطراف في الشبكة العامة .
    وعن مشكلة الحمايات الترددية والتي تعني فصل الأحمال الزائدة على توازن الشبكة في حال كان الاستهلاك أكبر من التوليد حيث أن ارتفاع الاستهلاك بشكل كبير وعدم قدرة مجموعات التوليد على تلبيته ، وهذا ممايؤدى إلى تفعيل هذه الحمايات وفصل الكهرباء حال كون التوليد لا يساوي الاستهلاك.


    لاإله إلا الله محمد رسول الله

  4. #4
    Consultant Engineer الصورة الرمزية أسامة حسن البلخي
    تاريخ التسجيل
    Sep 2014
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    رد: الحماية الترددية

    Protective relay


    Electromechanical protective relays at a hydroelectric generating plant. The relays are in round glass cases. The rectangular devices are test connection blocks, used for testing and isolation of instrument transformer circuits.


    In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is detected / The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, over-voltage, reverse power flow, over-frequency, and under-frequency. ]
    Microprocessor-based digital protection relays now emulate the original devices, as well as providing types of protection and supervision impractical with electromechanical relays. Electromechanical relays provide only rudimentary indication of the location and origin of a fault. In many cases a single microprocessor relay provides functions that would take two or more electromechanical devices. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. However, due to their very long life span, tens of thousands of these "silent sentinels" are still protecting transmission lines and electrical apparatus all over the world. Important transmission lines and generators have cubicles dedicated to protection, with many individual electromechanical devices, or one or two microprocessor relays.
    The theory and application of these protective devices is an important part of the education of a power engineer who specializes in power system protection. The need to act quickly to protect circuits and equipment as well as the general public often requires protective relays to respond and trip a breaker within a few thousandths of a second. In some instances these clearance times are prescribed in legislation or operating rules. A maintenance or testing program is used to determine the performance and availability of protection systems. ]
    Based on the end application and applicable legislation, various standards such as ANSI C37.90, IEC255-4, IEC60255-3, and IAC govern the response time of the relay to the fault conditions that may occur. ]


    وظيفة الحمايات الترددية في الشبكة هو الحفاظ على التردد في الشبكة بقيمة 50 HZ - فإذا زاد الاستهلاك على قيمة الانتاج بأكثر من 5 % .. ساافعل الخمايات الترددية وتفصل أحمال الأطراف في الشبكة العامة .
    وعن مشكلة الحمايات الترددية والتي تعني فصل الأحمال الزائدة على توازن الشبكة في حال كان الاستهلاك أكبر من التوليد حيث أن ارتفاع الاستهلاك بشكل كبير وعدم قدرة مجموعات التوليد على تلبيته ، وهذا ممايؤدى إلى تفعيل هذه الحمايات وفصل الكهرباء حال كون التوليد لا يساوي الاستهلاك.


    http://www.sayedsaad.com/montada/showthread.php?t=6393
    لاإله إلا الله محمد رسول الله

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