Regulation for Electrical Railway Track Crossings
78 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the requirement for power line crossings up to and including 11kV?

  • They can be either overhead or underground at the discretion of the railway.
  • They must be cabled and crossed underground. (correct)
  • They require a minimum height of 10 meters above the rail level.
  • They can be overhead without any restrictions.

    • What is the minimum height requirement for an overhead crossing of power lines ranging from 66kV to 132kV?

  • 14.60 meters (correct)
  • 17.90 meters
  • 15.40 meters
  • 14.10 meters

    • What is the coefficient kr for a single track section with 2 rails available for traction current?

  • 0.56 (correct)
  • 0.39
  • 0.53
  • 0.69

    • What is the cable screening factor Kc for bare conductors?

    <p>1</p> Signup and view all the answers

    What angle is generally required for overhead crossings relative to the railway track?

    <p>It must be perpendicular to the track.</p> Signup and view all the answers

    In exceptional circumstances, what is the maximum allowed deviation angle for power line crossings from the perpendicular?

    <p>30 degrees</p> Signup and view all the answers

    What modifies the voltage rise on an overhead conductor for different environments?

    <p>The length of parallelism</p> Signup and view all the answers

    What consideration is given to the clearance between the lowest conductor of a power line and the highest traction conductor?

    <p>Clearances are indicated for most adverse ambient temperature conditions.</p> Signup and view all the answers

    If the current in the OHE is 600 A, what is the modified figure for a single track with maximum current of 300 A?

    <p>300/600</p> Signup and view all the answers

    What is the recommended crossing method for power lines up to and including 33kV?

    <p>They should be crossed using underground cables.</p> Signup and view all the answers

    Under what earth conductivity condition is Table 9.1 applicable?

    <p>8 x 10 -2 S/m</p> Signup and view all the answers

    What is the maximum current allowed on a single track section as per the conditions specified?

    <p>300 A</p> Signup and view all the answers

    For power lines above 500kV, what is the minimum height above rail level required?

    <p>23.40 meters</p> Signup and view all the answers

    What empirical method is mentioned for establishing the values of kr?

    <p>SNCF standards</p> Signup and view all the answers

    What is a significant consideration when modifying power line crossings?

    <p>High costs and difficult shutdowns are substantial concerns.</p> Signup and view all the answers

    What is the minimum height required for power lines ranging from above 11kV to 66kV?

    <p>14.10 meters</p> Signup and view all the answers

    What impacts the mutual inductance M on an overhead conductor?

    <p>Earth resistivity and conductor distance</p> Signup and view all the answers

    What is the voltage rise on an overhead distribution line due to induction from traction current derived from?

    <p>Empirical research</p> Signup and view all the answers

    What oversight is mentioned regarding deviations over 30 degrees for overhead crossings?

    <p>They must be approved by the Chief Electrical Engineer.</p> Signup and view all the answers

    For a section with double track and all four rails available for traction current, what current is assumed in the OHE?

    <p>600 A</p> Signup and view all the answers

    What is the minimum clearance for voltage levels above 110 kV but up to 132 kV?

    <p>5.05 m</p> Signup and view all the answers

    What is the minimum clearance from the guard wire to the highest traction conductor?

    <p>2 m</p> Signup and view all the answers

    What is the safe electro-magnetically induced voltage limit for installations accessible to the public or untrained staff?

    <p>25V</p> Signup and view all the answers

    How many points should the neutral of a 3-phase, 4-wire earthed system be earthed at?

    <p>One point</p> Signup and view all the answers

    What is the maximum allowable electro-statically induced discharge current?

    <p>8 mA</p> Signup and view all the answers

    What condition must be met for maintenance personnel regarding the 25 kV system?

    <p>Stay outside 2 m of the nearest point</p> Signup and view all the answers

    What is the maximum electro-magnetically induced voltage in long metallic structures such as fencing?

    <p>25V</p> Signup and view all the answers

    Which formula represents the condition for calculating electro-magnetically induced voltage?

    <p>E = 2π * Kr * Kc * M * I * L</p> Signup and view all the answers

    What must be ensured regarding electro-magnetically induced voltage for installations with trained personnel only?

    <p>Does not exceed 60V</p> Signup and view all the answers

    If safety conditions for a distribution system are not met, what action is required?

    <p>Modify the overhead distribution system</p> Signup and view all the answers

    What is the value of Kr applicable for a single track, single rail section?

    <p>0.69</p> Signup and view all the answers

    How should the voltage rise be modified when using booster transformers and return conductors?

    <p>Divided by 2.3</p> Signup and view all the answers

    In a double track section electrified at 25 kV, what is the total project length of the overhead line?

    <p>0.8 km</p> Signup and view all the answers

    What is the average offset distance between the two lines considered in the electrified route?

    <p>16 m</p> Signup and view all the answers

    Which method can be used to bring induced voltage down to safe limits?

    <p>Shorten the feeding distance</p> Signup and view all the answers

    What would the expected voltage rise be if all four rails were available for traction currents?

    <p>36 V</p> Signup and view all the answers

    What is one of the options to provide safe voltage limits during electromagnetic induction conditions?

    <p>Install lead sheathed or aluminum sheathed cables</p> Signup and view all the answers

    What is the purpose of sectionalizing the distribution line?

    <p>To isolate sections for maintenance</p> Signup and view all the answers

    What voltage is used for auxiliary transformers in the context provided?

    <p>240 V</p> Signup and view all the answers

    What factor is used to modify results when considering the change from double track to single track?

    <p>0.69</p> Signup and view all the answers

    What is the minimum height requirement above rail level for overhead power lines exceeding 220kV?

    <p>17.90 m</p> Signup and view all the answers

    What is the recommended action for power line crossings exceeding 33kV when underground crossing is not possible?

    <p>To seek electrical inspector approval for lower heights</p> Signup and view all the answers

    What is the minimum clearance required for voltage levels above 66 kV but up to 110 kV?

    <p>4.75 m</p> Signup and view all the answers

    What is the angle of deviation allowed for overhead crossings in exceptional cases?

    <p>30 degrees</p> Signup and view all the answers

    For overhead crossings with voltage levels from 500kV to 800kV, what is the minimum height required above rail level?

    <p>23.40 m</p> Signup and view all the answers

    What must be ensured for maintenance personnel regarding the 25 kV system?

    <p>They must be trained and authorized</p> Signup and view all the answers

    According to the conditions for electro-magnetically induced voltage, what is the safe limit for installations accessing the public or untrained staff?

    <p>25 V</p> Signup and view all the answers

    What is the purpose of insisting on underground cables for power lines up to 11kV?

    <p>To prevent direct contact with animals</p> Signup and view all the answers

    What is the maximum electro-statically induced discharge current allowed?

    <p>8 mA</p> Signup and view all the answers

    What clearance must be maintained between the lowest conductor of a power line and the highest traction conductor under adverse conditions?

    <p>As specified by electrical inspector</p> Signup and view all the answers

    For a 3-phase, 4-wire earthed system, where should the neutral be earthed?

    <p>At only one point, at the substation</p> Signup and view all the answers

    What criteria dictate the minimum height of conductors for overhead crossings between 11kV and 66kV?

    <p>Height above rail level and safety regulations</p> Signup and view all the answers

    What action should be taken if it is anticipated that the deviation angle for overhead crossing will exceed the permissible limit?

    <p>Report to the Chief Electrical Engineer</p> Signup and view all the answers

    What is the maximum electro-magnetically induced voltage allowed in long metallic structures such as fencing?

    <p>25 V</p> Signup and view all the answers

    Which of the following is true regarding the angle of overhead crossings in relation to the track?

    <p>Must be perpendicular unless approved otherwise</p> Signup and view all the answers

    What is the formula adopted for calculating the Electro-magnetically induced voltage?

    <p>E = 2π.Kr.Kc.M.I.L</p> Signup and view all the answers

    For power lines above 132kV to 220kV, what is the minimum height requirement?

    <p>15.40 m</p> Signup and view all the answers

    What should be maintained regarding electro-magnetically induced voltage for installations accessible to trained personnel only?

    <p>It should not exceed 60 V</p> Signup and view all the answers

    What is the minimum clearance required between the guard wire and the highest traction conductor?

    <p>2 m</p> Signup and view all the answers

    What is the value of the cable screening factor Kc for lead sheathed underground cables?

    <p>0.8</p> Signup and view all the answers

    Which current corresponds to the given conditions for a double track section with all four rails available for traction current?

    <p>600 A</p> Signup and view all the answers

    How must the voltage rise figure be modified for a single track section with one rail available for traction current?

    <p>It should be reduced by half.</p> Signup and view all the answers

    What is the relationship between mutual inductance M and the average distance between conductors?

    <p>M decreases with an increase in distance.</p> Signup and view all the answers

    For which earth conductivity value is Table 9.1 considered safe and applicable?

    <p>8 x 10 -2 S/m</p> Signup and view all the answers

    What value should the coefficient kr be set at for a single track with one rail available for traction current?

    <p>0.53</p> Signup and view all the answers

    What factor determines the voltage rise on an overhead distribution line due to induction from traction current?

    <p>All of the above</p> Signup and view all the answers

    What must be the condition for a voltage rise figure obtained for overhead conductors in modified environments?

    <p>It must be modified appropriately based on environmental factors.</p> Signup and view all the answers

    The average distance for determining the value of mutual inductance M is based on what measurement?

    <p>Projected length on the alignment of OHE</p> Signup and view all the answers

    What should the result obtained be modified by when changing from a double track to a single track section?

    <p>Multiply by 0.69</p> Signup and view all the answers

    When using a booster transformer spacing of 2.66 km, how should the voltage rise be approximated?

    <p>Divide by 2.3</p> Signup and view all the answers

    What average offset distance was considered in the electrified route for the overhead line?

    <p>16 m</p> Signup and view all the answers

    In the context provided, what is a potential method for reducing excessive induced voltage?

    <p>Shift the point of feed to the center</p> Signup and view all the answers

    What voltage was induced in the system when only two rails were taken for return current near a station?

    <p>50 V</p> Signup and view all the answers

    If all four rails were utilized for traction currents, what would the expected voltage rise be?

    <p>36 V</p> Signup and view all the answers

    What is one of the methods mentioned to reduce induced voltage caused by electromagnetic induction?

    <p>Cable the overhead line in aluminum sheathed cables</p> Signup and view all the answers

    If the induced voltage exceeds permissible limits, which of the following strategies can be used?

    <p>Sectionalize the distribution line</p> Signup and view all the answers

    What is the consequence of high induced voltage in an electrified rail environment?

    <p>Safety hazards for operating personnel</p> Signup and view all the answers

    What spacing is suggested for booster transformers to reduce voltage rise effectively?

    <p>2.66 km and 4 km</p> Signup and view all the answers

    Study Notes

    Regulation for Electrical Crossing of Railway Tracks

    • Regulations for power line crossings of railway tracks were established in 1987.
    • Power lines up to 11kV should be cabled and buried underground.
    • Power lines 33kV and below are recommended for underground cabling.
    • For overhead crossings, the minimum height above rail level is dependent on the voltage.
      • 11-66 kV: 14.10 meters
      • 66-132 kV: 14.60 meters
      • 132-220 kV: 15.40 meters
      • 220-400 kV: 17.90 meters
      • 400-500 kV: 19.30 meters
      • 500-800 kV: 23.40 meters
    • Overhead crossing angles should be perpendicular to the track, except in exceptional cases (deviation maximum 30 degrees).
    • Electrical inspectors may allow lower heights if the clearance between the lowest power line conductor and the highest traction conductor is adequate under adverse temperature conditions.
      • Clearances for different voltage ranges are given. (Refer to document for specifics)
    • Power line crossings must maintain a 2-meter clearance between the guard wire and the highest traction conductor.

    Overhead Distribution System

    • Overhead distribution systems must maintain adequate clearance to allow personnel maintenance access, preventing personnel from getting too close to high voltage areas. (greater than 2 meters.)
    • Electromagnetically induced (EMI) voltages within the distribution system caused by adjacent 25kV traction currents must be within safe limits.
    • Electrostatic discharge currents must stay within safe limits between the 25kV system and the power distribution system.
    • Installations may have to be modified when safety standards for electromagnetic and electrostatic limitations are not met,
    • Safe limits for electromagnetically induced voltage are defined for different access levels (trained personnel vs. public).
    • Safe limits for electrostatic discharge current are provided.
    • Electro-magnetically induced voltage in metallic structures like fences and bridges should not exceed 25 volts.

    Voltage Rise from Induction

    • Tables provide voltage rise in overhead distribution lines due to traction currents.
    • Calculations consider factors such as:
      • Track conditions (single vs. double track, rail availability)
      • Earth conductivity
      • Current in the overhead line
    • Formulae for Electro-magnetically induced voltage are given
    • Calculations for different conditions (single/double track, rail availability, booster transformers) are provided to reduce the voltage rise.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Regulation for Electrical Crossing of Railway Tracks PDF

    Description

    This quiz covers the regulations established in 1987 concerning power line crossings over railway tracks. It includes guidelines for underground cabling, minimum height requirements based on voltage levels, and specific conditions for electrical inspectors. Test your knowledge on the essential rules governing safe electrical crossings.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser