Power Generation and Transmission Quiz
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Questions and Answers

What is the primary advantage of AAAC conductors over ACSR conductors?

  • Better electrical insulation
  • Lower conductivity
  • Higher strength
  • Lighter weight and better corrosion resistance (correct)

    • AAAC conductors are preferred for high-voltage transmission due to their high tensile strength.

    False

    What alloy is used to make AAAC conductors?

    Aluminium-Magnesium-Silicon alloy

    The main purpose of using galvanized steel in ACSR conductors is to prevent ______.

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

    Match the following types of conductors with their primary characteristics:

    <p>AAC = Limited use in transmission due to poor strength AAAC = Good conductivity with better mechanical strength ACSR = Increased tensile strength with galvanized steel core Bundled conductors = Improved heat dissipation and reduced corona losses</p> Signup and view all the answers

    What is the typical configuration for bundled conductors in 220 kV lines?

    <p>Two-conductor bundles</p> Signup and view all the answers

    Bundling conductors helps to reduce the inductance in high-voltage lines.

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

    What is the primary reason for increasing the surface area of conductors by bundling?

    <p>Increasing heat dissipation</p> Signup and view all the answers

    What happens to the inductance of a transmission line if the spacing between the conductors increases?

    <p>Inductance increases</p> Signup and view all the answers

    The inductance of a transmission line is independent of the radius of the conductors.

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

    What is the formula for the total inductance of a two-wire transmission line?

    <p>l = (μ / (2π)) * (1/D + ln(4r/D))</p> Signup and view all the answers

    The inductive reactance of a transmission line is denoted as _____ and depends on inductance and frequency.

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

    Match the terms with their definitions:

    <p>Inductance = Opposition to change of current Inductive Reactance = Opposition to alternating current Frequency = Number of cycles per second Power System = Network for electrical energy distribution</p> Signup and view all the answers

    What is the main factor that affects the series inductive reactance of a transmission line?

    <p>Inductance and frequency</p> Signup and view all the answers

    The length of the transmission line has no effect on the total series inductive reactance.

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

    What is the relationship between the radius of the conductors and the inductance of the line?

    <p>The greater the radius of the conductors, the lower the inductance of the line.</p> Signup and view all the answers

    What is the value of the total shunt admittance Yse for the given transmission line?

    <p>j 7.684 x 10^-5 S</p> Signup and view all the answers

    The shunt capacitive reactance is represented as a positive value.

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

    What type of conductor is used in the example for calculating the inductance and capacitance of the transmission line?

    <p>Composite (stranded) conductor</p> Signup and view all the answers

    The distance between two conductors in a balanced three-phase transmission line is represented by D = ______.

    <p>5m</p> Signup and view all the answers

    Which formula is used to calculate the inductance of each conductor?

    <p>$λa = \frac{µ_0}{2π} [ia \ln(\frac{1}{r'}) + ia \ln(\frac{1}{D})]$</p> Signup and view all the answers

    Match each term with its correct definition:

    <p>Shunt admittance = Total admittance per unit length of a transmission line Inductance = Opposition to the change of current in a conductor Capacitance = Ability of a conductor to store electronic charge Reactance = Resistance experienced by the flow of alternating current</p> Signup and view all the answers

    A balanced transmission line assumes equal currents in all three phases.

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

    The resistive part of the shunt admittance is represented as ______.

    <p>0</p> Signup and view all the answers

    What is the impact of conductor bundling on inductance?

    <p>Decreases inductance</p> Signup and view all the answers

    The total reactance for a 5-mile line calculated is 3.79 Ω.

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

    What is the typical number of conductors for 500 kV lines?

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

    The formula for calculating inductance per phase is La = ln(________) where the spacing is symmetric.

    <p>2πr'</p> Signup and view all the answers

    Match the following spacing configurations with their associated line types:

    <p>Symmetric spacing = No mutual inductance Asymmetric spacing = Mutual coupling Conductor bundling = Increased capacity Horizontal phase spacing = 10 meters</p> Signup and view all the answers

    What is the new inductance per meter when using four conductors in a square bundle with the given parameters?

    <p>7.46 × 10−7 H/m</p> Signup and view all the answers

    The conductor radius used in the calculations is 0.5 cm.

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

    What is the reactance formula used to calculate Aa for the three-phase line?

    <p>Xa = 2π × 60 × La</p> Signup and view all the answers

    What is the series resistance per kilometer of the transmission line?

    <p>0.0225 Ω/km</p> Signup and view all the answers

    The series inductance of the transmission line is irrelevant for impedance calculations.

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

    What is the resistivity of the line at 200°C?

    <p>2.83 × 10^{-8} Ω-m</p> Signup and view all the answers

    The formula for series inductance per kilometer is __________.

    <p>l = µ(1/4r + ln(D/4r)) × 1000</p> Signup and view all the answers

    What is the radius of each conductor in meters?

    <p>0.02 m</p> Signup and view all the answers

    Match the following components with their respective formulas:

    <p>Series Resistance = ρl/A Series Inductance = µ(1/4r + ln(D/4r)) Total Impedance = Z = R + jX Area = πr^2</p> Signup and view all the answers

    What frequency does the transmission line operate at?

    <p>60 Hz</p> Signup and view all the answers

    The total length of the transmission line is __________.

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

    What is the inductive reactance per mile for a Partridge conductor at 20 ft spacing operating at 60 Hz?

    <p>0.8285 Ω/mile</p> Signup and view all the answers

    The capacitive reactance between the conductor and the neutral can be determined from the given information.

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

    What is the GMR value for the Partridge conductor?

    <p>0.0217 ft</p> Signup and view all the answers

    The inductive reactance for the entire length of the ACSR Drake line is __________.

    <p>To be calculated based on inductive reactance per mile and line length.</p> Signup and view all the answers

    Match the following reactances to their respective terms:

    <p>Inductive Reactance per Mile = 0.8285 Ω/mile Capacitive Reactance to Neutral = Value not provided Charging Current = To be calculated Charging Reactive Power = To be calculated</p> Signup and view all the answers

    What is the calculated inductive reactance for one mile of the ACSR Drake line?

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

    The spacing factor is irrelevant to the calculation of inductive reactance.

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

    What is the normal operating voltage mentioned for the three-phase line?

    <p>220 kV</p> Signup and view all the answers

    Study Notes

    Power Generation and Transmission

    • Types of Conductors:
      • Copper: Strong, good conductivity, high current density, durable, high scrap value
      • Aluminum: Cheaper than copper, lighter, second-best conductivity, lower tensile strength, prone to damage from heat
      • Steel: High tensile strength, but low conductivity, used for ground wires
      • Steel-cored Aluminum: Strength of steel and conductivity of aluminum.
      • AAC (All Aluminum Conductor): Good conductivity, but lower strength.
      • AAAC (All Aluminum Alloy Conductor): Higher strength and conductivity than AAC, used for rural distribution
      • ACSR (Aluminum Conductor Steel Reinforced): Strength of steel and conductivity of aluminum, used for high-voltage transmission
      • ACAR (Aluminum Conductor Alloy Reinforced): Alloy conductors, mainly used in coastal areas for better corrosion resistance

    Conductor Selection Considerations

    • High Tensile Strength: Material in conductors must handle high loads to prevent sagging in long spans.
    • Low Resistivity: Reducing power losses and voltage drop, which saves money and energy.
    • Low Cost: Economic conductor materials.
    • Low Corrosion: Stable conductors prevent degradation and maintain reliability.
    • Low Skin Effect & Corona Losses: Specific conductor structure minimizes losses related to high voltages, such as skin effect, this improves efficiency and reduces cost

    Bundling of Conductors

    • Heat Dissipation: Increases surface area aiding efficient heat dissipation.
    • Reducing Corona Losses: Bundling decreases corona discharge, enhancing efficiency and reducing energy loss in high-voltage lines
    • Reducing Inductance: Fewer currents running parallel to each other reduce inductance, improving performance
    • Increasing Current Capacity: Bundled conductors lower the overall effect of the skin effect which increases current capacity, improving efficiency.
    • 220 kV lines: Typically use two conductor bundles
    • 380 kV lines: Typically use three or more conductor bundles

    Inductance of Single-Phase Two-Wire Transmission Line

    • Internal inductance + external inductance between the conductor and the surrounding space
    • Permeability is the degree to which a material permits the formation of magnetic flux.
    • Inductance (l) is proportional to the permeability (µ)
    • Inductance is inversely proportional to the natural logarithm of the radius (r),
    • Inductance is proportional to the separation distance (D).
    • The total inductance of the other wire is the same.
    • The total inductance of a two-wire transmission line is proportional to the (ln(D)).

    Inductance of a Transmission Line

    • Spacing between phases of transmission line increases inductance.
    • Increased radius of conductors in a transmission line decreases inductance.

    Capacitance of a Single-Phase Two-Wire Transmission Line

    • Capacitance (C) is directly proportional to the permeability (ɛ)
    • Capacitance is inversely proportional to the natural logarithm of the radius (r),
    • Capacitance is inversely proportional to the separation distance (D). The capacitance to ground is one half the capacitance between conductors.

    Capacitance in a Transmission Line

    • The greater the spacing between the phases of a transmission line, the lower the capacitance of the line.
    • The greater the radius of the conductors in a transmission line, higher the capacitance of the line.

    Shunt Capacitive Admittance

    • Shunt capacitive admittance depends on capacitance and power system frequency.
    • Total shunt capacitive admittance is proportional to the frequency (f) and capacitance per unit length (c).
    • Total shunt capacitive admittance is directly proportional to the length of the line (d).
    • Capacitive reactance is the reciprocal of the admittance.

    Example Calculations

    (Specific calculation details are included in the pages of the notes, which are provided in the text you uploaded)

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    Related Documents

    ELE 2303 Power Generation and Transmission PDF

    Description

    Test your knowledge on various types of conductors used in power generation and transmission. This quiz covers materials like copper, aluminum, and steel, as well as their properties and applications. Learn about the selection considerations necessary for effective conductor use.

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