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الموضوع: كتاب تحديد أعطال الكابلات لباري كلج(ملخص)

  1. #1
    مشرف قسم الكابلات الأرضية الصورة الرمزية م. كامل بدرخان
    تاريخ التسجيل
    Feb 2007
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    السعودية
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    كتاب تحديد أعطال الكابلات لباري كلج(ملخص)

    السلام عليكم ورحمة الله وبركاته
    الكتاب كبير زكلما ألخص باب سأرسله لكم لنتواصل ونستفيد إن شاء الله
    Underground cable fault location

    Third edition

    Barry clegg

    The author started his book by these important words:

    (To my wife , without whose love , tolerance , forbearance and support over many years , this book could not have been written) .

    Preface :

    Cable fault location is more of an art than a science . Although it is a technical subject all faults are different and success depends to a great extend on practical aspects and the experience of the operator .
    Engineers engaged in fault location are often handicapped in that :
    1-) They may not have received through training .
    2-) The range of equipment at their disposed will usually be limited .
    3-) Detailed information on methods and instruments may well not be available .
    This book is a reference for information& knowledge of fault location , tracing , identification and safety .
    The first edition was published 1993 .
    The third edition includes new chapters , more details , safety , training , and updated equipments .

    Introduction :

    Each fault location is a drama – a detective story in which the sagacious operator makes a careful analysis of the evidence and applies sound logical procedures that lead inexorably and speedily to a correct location .
    Or each fault location is an embarrassing nightmare of trial and error and miscalculation leading to an eventual location .
    All fault locations are successful , But at what cost in time and money , and how many joints are added to the network in the process?
    There are many difficulties such as : the cable can be shallow or deep , the route may be under buildings or rubbish tips .
    You must make a good team (engineer and supervisor which have more common sense and experience ) .
    Also people who dig holes must have much experience of types of cables and their habits.










    Part one ( general):

    Chapter 1 :

    What is a fault ?




    Fault:
    Any defect, weakness, non-homogeneity that affects the performance of a cable.
    Fault Types:
    1-) Contact fault
    Occurs between (core & core) or (core & sheath) (short or shunt fault)
    2-) Ground (Earth) contact fault
    Occurs between (core’s & mass of earth), it occurs on unshielded multi-core (control & telecommunication) cables and also happens between sheath and mass of earth (fault between sheath & mass of earth can be pin-pointing using H V DC or audio frequency methods while pre-location can be carried out by using BRIDGE but pulse echo cannot be used. .
    3-) Break
    Called open circuit or series fault A-)clean (infinity or very high resistance), B-) dirty (resistance), C-) partial (some of the strands of a conductor are broken or burnt)
    4-) Ingress of moisture
    Moisture usually produce contact fault involving all cores and changes the characteristic of the cable’s impedance.
    Plastic cables can often perform when wet; paper cables cannot
    5-) Crimping
    It happens greatly in communication cables and causes contact fault & can be
    Located by:
    TDR method.
    6-) Cross talk
    7-) Flashing fault
    May occur through the high voltage test and in the weaken point making a spark gap.
    8-) Transitory
    It occurs on low voltage networks , it causes a fuse to blow and then
    disappears.
    9-) Partial Discharge
    It is a phenomenon occurring on the high voltage systems whereby small breakdowns occur at weak point in the insulation e.g. voids.The energy is measured in PC (Pico coulombs) . Treeing is a common manifestation of the partial discharge
    Treeing: i.e. carbon tracking on insulation .
    Monitoring of PD measurement can be taken (off line & on line) (details are
    covered in part six and appendices).

  2. #2
    مشرف قسم الكابلات الأرضية الصورة الرمزية م. كامل بدرخان
    تاريخ التسجيل
    Feb 2007
    الدولة
    السعودية
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    9,942

    رد: كتاب تحديد أعطال الكابلات لباري كلج(ملخص)

    السلام عليكم ورحمة الله وبركاته
    وهذه ترجمة الكلمات الصعبة لهذا الجزء
    Barry clegg book

    Article مقالة - فقرة
    Engage يشغل – يتعهد ب
    Handicapped معاق
    Preface تقديم – واجهة
    Aspects مظاهر
    Alike متشابه – سواء – الطريقة نفسها
    Attempt يحاول
    Incorporate يندمج – يجسد
    Publisher ناشر
    Cognition معرفة
    Disposed ميال إلى – مطبوع على
    Particular شخصي – مفرد – هام – خاص
    Illustration مثل – تزين
    Advertisements إعلانات
    Currently الآن في الوقت الحاضر
    Brilliant متألق – رائع – لامع
    Detective كشفي – بوليس سري
    Sagacious حصيف
    Evidence دليل – شاهد – بيئة
    Inexorable عنيد
    Exorable لين العريكة
    Embarrassing إلى حد مربك
    Nightmare كابوس
    Eventual نهائي
    Abandoned متحرر من القيود – مهجور
    Evaluate يقدر – يثمن
    Evacuate يفرغ
    Trending ميل
    Severity صرامة
    Involvement استخدام
    Acknowledgment شكر – اعتراف
    Tolerance – forbearance احتمال – صبر
    Terrain منطقة – حقل
    Grasp يمسك ب – يعانق – يفهم
    Versed متمكن
    Villain ساذج – وغد
    Anatomy تحليل – علم التشريح
    Perform يفي
    Crimping تجعد
    Severe بسيط
    Packing صندوق التعبئة
    Manifestation إظهار – إبداء
    Lengthening امتداد
    Incursion غزوة
    Track اثر – درب – خط سكة حديد – تسلسل أفكار
    Appendices ملحقات – زوائد
    Tipsy مترنح

  3. #3
    Consultant SCADA & AMI الصورة الرمزية موسى سعيد أبو خطوه
    تاريخ التسجيل
    Jul 2006
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    طنطا - مصر
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    رد: كتاب تحديد أعطال الكابلات لباري كلج(ملخص)

    شكراً لك مهندس / كامل بدرخا ن
    على هذا المجهــــــــــــــــــــــــــــود
    ولكن يفضل إرفاق الملف الخا ص
    بالكتاب حتى تعم الفائده للجميـــــع

    ولك منى الشكر والتحيـــــــــــــــــه



    م/ موسى أبو خطـــــــــــــــــــــوه

  4. #4
    مشرف قسم الكابلات الأرضية الصورة الرمزية م. كامل بدرخان
    تاريخ التسجيل
    Feb 2007
    الدولة
    السعودية
    المشاركات
    9,942

    رد: كتاب تحديد أعطال الكابلات لباري كلج(ملخص)

    السلام عليكم ورحمة الله وبركاته
    م موسى
    أنا لدي الكتاب فقط ولكنه أيضا موجود بالنت موقعwww.cable fault location.com مع خالص تحياتي

  5. #5
    مشرف قسم الكابلات الأرضية الصورة الرمزية م. كامل بدرخان
    تاريخ التسجيل
    Feb 2007
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    تابع كتاب تحديد أعطال الكابلات لباري كلج

    السلام عليكم ورحمة الله وبركاته
    Chapter 2 :


    . Fault Causes

    1- Cable type and length
    a- type of cable and different dielectrics produce different fault characteristic and often dictate different approach.
    b- very long cable pose problem for PE/TDR and more difficult to trace and measure.
    2- Cable laying you must avoid damage such as over sheath abrasion, puncture,& moisture ..etc.
    3- Joints and jointing
    a- quality of materials
    b- workmanship is a problem as people are often working in a difficult environment and under pressure
    c- quality of training and supervision
    4- Network this occurs at LV network ( multi – teed system) when fault can be located by re-energizing.
    5- Environment
    a- depth
    b- Temperature
    c- Type of cover
    d- Ground surface
    e- Vibration
    f- Vermin
    g- Subsidence
    h- Proximity of structures, hazards and other services
    i- weather
    6- Operation
    a- protection type and setting

    b- loading and load cycling that can cause overheating movement and migration of joint dielectric
    c- repeated re-energizing of fault
    7- Testing
    a- e.g. VLF better than HV DC for the test, which does less damage and gives a much better indication of failure and potential failure
    b- even aspects of the faults location process itself such as Burn-down and Shock-wave discharging (Burning or thumping) can adversely affect a cable and cause breakdown at other sites at the time of testing or later
    8- Third party damage
    Damage to the cable by other authorities or contractors occurs often

  6. #6
    V.I.P Member الصورة الرمزية حازم عدنان مهدي
    تاريخ التسجيل
    Mar 2007
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    رد: كتاب تحديد أعطال الكابلات لباري كلج(ملخص)

    السلام عليكم ورحمة الله وبركاته
    ارجو المساعدة بارسال جدول يبين حجم الكيبل وكم يتحمل من امبير وفولتية او قانون اعتماد علية



    شكراً لك اخي الكريم

  7. #7
    مشرف قسم الكابلات الأرضية الصورة الرمزية م. كامل بدرخان
    تاريخ التسجيل
    Feb 2007
    الدولة
    السعودية
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    رد: كتاب تحديد أعطال الكابلات لباري كلج(ملخص)

    السلام عليكم ورحمة الله وبركاته
    م.حازم عدنان تم إرسال الجدول المطلوب وهو لكابلات 132 ك ف تحت عنوان (جدول العلاقة بين المساحة والتيار لكابلات 132ك ف

  8. #8
    مشرف قسم الكابلات الأرضية الصورة الرمزية م. كامل بدرخان
    تاريخ التسجيل
    Feb 2007
    الدولة
    السعودية
    المشاركات
    9,942

    تابع كتاب تحديد أعطال الكابلات لباري كلج(الفصل الثالث)

    السلام عليكم ورحمة الله وبركاته
    Chapter 3 :

    The proper approach

    You must avoid : 1-) wrong conclusions & 2-) destroying a fault condition
    As an example: though burn down is occasionally (sometimes) necessary, it can also destroy a condition that might otherwise have been very useful in pre-location or pin-pointing the fault.
    Safety:
    1-) No action should ever be taken on a signal
    2-) The conductor should never be touched until it has been earthed.
    3-) All cables & equipment should be discharged after testing.

    The steps in a correct approach are:
    - Diagnosis
    - Pre-location
    - Pin-pointing
    - Confirmation & re-test
    - Recording
    - Reporting
    Diagnosis:
    You should proceed slowly & carefully as follows:
    1-) Ask the people on site about everything (cable type, length, how fault occurred, protection operation etc)
    2-) Believe only what is most probably true
    3-) Check everything yourself
    4-) Test the insulation resistance between conductors & sheath and record values
    5-) Look at the cable with a pulse echo set (TDR)
    6-) Write everything down for the future for you & others
    7-) Keep your mind clear to avoid mistakes

    For instance, knowing the type of cable will assist your thought processes. Can an XLPE(cross-linked polyethylene) cable be burnt down? No.
    Would you expect to find a core-to-core fault on a cable with screened cores? No.
    Would you normally expect a zero ohm fault on one phase of an unearthed high voltage cable system? No.

    Pre-location
    A pre-location is any test that is carried out and results in a calculation of the distance to the fault.
    The main pre-location methods are: Resistance Bridge, Pulse Echo/TDR or Transient (ARM,ICE,etc)
    Even though every effort is made to carry out the test with great accuracy, the result will usually be approximate, particularly on a long cable.
    1-)Unknown loop of cable makes the route length measurement inaccurate.
    2-) Cable of different size & type makes fault distance inaccurate.
    3-) 10Km cable long makes calculations inaccurate.
    So, pre-location can be only expected to give a (suspect area) within which the fault lies.

    Pin-pointing:
    Pin pointing is the application of a test that positively confirms the exact position of the fault (by shock wave discharge or audio frequency.
    Shock wave discharge:
    HV capacitors are repeatedly discharged into the fault. The energy dissipated at the fault position creates a noise that can be heard with a sensitive ground microphone and amplifier.
    Audio frequency:
    It involves injecting signals of between several hundred & thousand HZ into the faulty core. A search coil & amplifier are then used to detect a change or cessation (stop) of signal over the fault (chapter 4 has details).

    Confirmation:
    The fault must be confirmed visually (obvious or hidden).
    It is good practice to photograph the faulty cable.

    Recording:
    Fault results, new joints, excavation problems should be recorded.

    Reporting:
    Such as: time of fault occurrence, cause, age and type of cable.

  9. #9
    مشرف قسم الكابلات الأرضية الصورة الرمزية م. كامل بدرخان
    تاريخ التسجيل
    Feb 2007
    الدولة
    السعودية
    المشاركات
    9,942

    تابع كتاب تحديد أعطال الكابلات لباري كلج

    السلام عليكم ورحمة الله وبركاته
    Chapter 3 :

    The proper approach

    You must avoid : 1-) wrong conclusions & 2-) destroying a fault condition
    As an example: though burn down is occasionally (sometimes) necessary, it can also destroy a condition that might otherwise have been very useful in pre-location or pin-pointing the fault.
    Safety:
    1-) No action should ever be taken on a signal
    2-) The conductor should never be touched until it has been earthed.
    3-) All cables & equipment should be discharged after testing.

    The steps in a correct approach are:
    - Diagnosis
    - Pre-location
    - Pin-pointing
    - Confirmation & re-test
    - Recording
    - Reporting

    Diagnosis:

    You should proceed slowly & carefully as follows:
    1-) Ask the people on site about everything (cable type, length, how fault occurred, protection operation etc)
    2-) Believe only what is most probably true
    3-) Check everything yourself
    4-) Test the insulation resistance between conductors & sheath and record values
    5-) Look at the cable with a pulse echo set (TDR)
    6-) Write everything down for the future for you & others
    7-) Keep your mind clear to avoid mistakes
    For instance, knowing the type of cable will assist your thought processes. Can an XLPE(cross-linked polyethylene) cable be burnt down? No.
    Would you expect to find a core-to-core fault on a cable with screened cores? No.
    Would you normally expect a zero ohm fault on one phase of an unearthed high voltage cable system? No.

    Pre-location:

    A pre-location is any test that is carried out and results in a calculation of the distance to the fault.
    The main pre-location methods are: Resistance Bridge, Pulse Echo/TDR or Transient (ARM,ICE,etc)
    Even though every effort is made to carry out the test with great accuracy, the result will usually be approximate, particularly on a long cable.
    1-)Unknown loop of cable makes the route length measurement inaccurate.
    2-) Cable of different size & type makes fault distance inaccurate.
    3-) 10Km cable long makes calculations inaccurate.
    So, pre-location can be only expected to give a (suspect area) within which the fault lies.

    Pin-pointing:

    Pin pointing is the application of a test that positively confirms the exact position of the fault (by shock wave discharge or audio frequency.
    Shock wave discharge:
    HV capacitors are repeatedly discharged into the fault. The energy dissipated at the fault position creates a noise that can be heard with a sensitive ground microphone and amplifier.
    Audio frequency:
    It involves injecting signals of between several hundred & thousand HZ into the faulty core. A search coil & amplifier are then used to detect a change or cessation (stop) of signal over the fault (chapter 4 has details).

    Confirmation:

    The fault must be confirmed visually (obvious or hidden).
    It is good practice to photograph the faulty cable.

    Recording:

    Fault results, new joints, excavation problems should be recorded.

    Reporting:

    Such as: time of fault occurrence, cause, age and type of cable.

  10. #10
    مشرف قسم الكابلات الأرضية الصورة الرمزية م. كامل بدرخان
    تاريخ التسجيل
    Feb 2007
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    رد: تابع كتاب تحديد أعطال الكابلات لباري كلج

    Chapter 4:

    Diagnosis & pre-location:

    Diagnosis:

    After recording all facts & details of faulty cable, insulation resistance tests must be applied to the cable cores.
    First tests be carried out with an ohmmeter using a low test voltage of just a few volts for these two reasons:
    1-) To avoid path breakdown & to get good picture by pulse echo.
    2-) Using high voltage from insulation resistance test set may modify the fault condition and make it unstable.
    Sometimes readings differ when the polarity of the test leads is reversed, due to electrolytic action at the fault and often indicates the presence of moisture.
    The result of this test will be apparent which cores are faulty and to what degree i.e. high/low resistance to earth /between cores and whether there are any open circuits.
    Second test is continuity which is normally carried out by (shorting) the conductors at the remote end to earth and/or between cores. Also loop resistance must be measured (reading should be fractions of an ohm on power cables and tens or hundreds of ohms on telecommunications cables.
    Any imbalance between readings on different cores indicates the presence of a series fault with some resistance.
    Now you can take a look at the cable with a PE set (pulse echo).
    If fault resistance is small, the fault will be visible with a PE.
    If fault resistance is too high, no fault will be visible with a PE but you can see joints & cable end.
    Also continuity can be carried out with a PE by applying short at the remote end.
    Put a PE trace (wave) in the memory to compare it with other after changing fault condition (by burning, surging, etc.).
    What a shame if no initial trace is taken and the fault condition subsequently changed.

    Pre-location:

    Now pre-location method can be chosen depending on fault condition, instrument available, cable length, &route and termination.
    Equipments are:
    Bridge (with or without burn-down).
    PE (with or without burn-down).
    Transient methods(impulse current or arc reflection).

    Bridge:
    Bridge can be used for contact(shunt) faults only, the measurement being made by balancing two internal resistances against two external resistances represented by the lengths of cable conductor up to the fault.
    Fault distance = 2* cable length* bridge reading.
    - Exact length of cable is very important for using bridge.
    - Short between healthy core to faulty core must be done at cable remote end (if you have double circuit only disconnect the faulty core from cable termination and connect bridge).
    We have DMB5 BAUR BRIDGE which has its LV DC & HV DC voltages.

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