Electrical Systems Quiz - Topic 6
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Questions and Answers

What is a primary topic covered in the Energy Engineering Fundamentals course?

  • Energy Storage Systems
  • Renewable Energy Technologies
  • Energy Policy Analysis
  • Power Generation (correct)

    • Which of the following is NOT considered a factor in system load analysis?

  • Usage type
  • Geographical constraints (correct)
  • End-usage
  • Time intervals

    • Which type of power cycle is included in the course curriculum?

  • Hydro power cycle
  • Biofuel cycle
  • Gas turbine cycle (correct)
  • Nuclear power cycle

    • What energy source is associated with solar thermal power?

    <p>Solar energy</p> Signup and view all the answers

    Which of the following best describes cogeneration?

    <p>Simultaneous generation of heat and power</p> Signup and view all the answers

    What is the purpose of electricity tariffs discussed in the course?

    <p>To determine the cost of electricity for consumers</p> Signup and view all the answers

    Which of the following end-usage items is specifically mentioned in the course outline?

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

    Which of these sectors is NOT mentioned in relation to system load types?

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

    What is the purpose of the diversity factor in energy planning?

    <p>To assist in capacity addition planning</p> Signup and view all the answers

    Which type of power plant is considered non-dispatchable?

    <p>Wind power plants</p> Signup and view all the answers

    What is the primary characteristic of a peak load power plant?

    <p>It operates only during high-demand periods</p> Signup and view all the answers

    What does the reserve factor represent in power systems?

    <p>The load factor divided by the capacity factor</p> Signup and view all the answers

    Why are dispatchable power plants valuable in an electric power system?

    <p>They provide spinning reserve and help with frequency control</p> Signup and view all the answers

    Which of the following statements about base load power plants is incorrect?

    <p>They are primarily powered by wind energy</p> Signup and view all the answers

    What does the coincidence factor inversely relate to?

    <p>Diversity factor</p> Signup and view all the answers

    Which of the following types of power generation can be made dispatchable with increased costs?

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

    What is the formula for calculating the reserve factor?

    <p>Load factor / Capacity factor</p> Signup and view all the answers

    What is an important benefit of using dispatchable power plants?

    <p>They help in balancing the electric power system</p> Signup and view all the answers

    Which publication focuses specifically on the economics of electric utility power generation?

    <p>Economics of Electric Utility Power Generation</p> Signup and view all the answers

    What is the main topic discussed in 'Power Plant Performance' by A.B. Gill?

    <p>Performance metrics for various power plants</p> Signup and view all the answers

    Which document is a critical review of advanced gas turbine cycles for power generation?

    <p>Advanced Gas Turbine Cycles for Power Generation: A Critical Review</p> Signup and view all the answers

    Which authors contributed to the research on energy management published in 2001?

    <p>S.Bandyopadhyay, N.C.Bera, and S.Bhattacharyya</p> Signup and view all the answers

    Who authored 'Electric Power System Planning: Issues, Algorithms and Solutions'?

    <p>Seifi H. and Sepasian M.S.</p> Signup and view all the answers

    What is the primary issue with low heat transfer coefficients in a power plant's design?

    <p>It requires larger heat transfer areas.</p> Signup and view all the answers

    What is the formula for turbine efficiency in a power plant?

    <p>$\eta_T = \frac{actual \ work}{ideal \ work \ Tin - Tout, \ s}$</p> Signup and view all the answers

    What is the general effectiveness range for modern gas turbine plants?

    <p>0.85 - 0.90</p> Signup and view all the answers

    Which material property primarily affects the maximum temperature capacity in a power plant?

    <p>Material type</p> Signup and view all the answers

    Why are turbines generally not used in moving plants?

    <p>They have a large pressure drop.</p> Signup and view all the answers

    What do the two isentropic work transfer processes in a Simple Plant represent?

    <p>Compression and expansion</p> Signup and view all the answers

    How is the effectiveness of heat transfer calculated?

    <p>$\epsilon = \frac{actual \ heat \ transfer}{maximum \ heat \ transfer}$</p> Signup and view all the answers

    What characterizes the operation of a Rankine cycle?

    <p>It consists of two heat transfer processes and two mechanical work processes.</p> Signup and view all the answers

    What components make up the ideal Brayton cycle?

    <p>Compressor, combustion chamber, and turbine</p> Signup and view all the answers

    Who first proposed the Brayton cycle?

    <p>George Brayton</p> Signup and view all the answers

    In a Brayton cycle, which of the following processes occur during its operation?

    <p>Two isentropic and two constant pressure processes</p> Signup and view all the answers

    What is the purpose of intercooling in a modified Brayton cycle?

    <p>To cool the combustion air between two compressors</p> Signup and view all the answers

    What effect does reheating have on cycle efficiency in a modified Brayton cycle?

    <p>It slightly decreases cycle efficiency</p> Signup and view all the answers

    Which assumption simplifies the analysis of the Brayton cycle?

    <p>Air is treated as an ideal gas with constant properties</p> Signup and view all the answers

    What is the role of the regenerator in a Brayton cycle?

    <p>To recover heat from the turbine exit and increase combustion air temperature</p> Signup and view all the answers

    What does the efficiency of the Brayton cycle depend on?

    <p>The specific heat ratio of the working fluid and the pressure ratio</p> Signup and view all the answers

    What is incompatible with gas turbine plants within the Brayton cycle?

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

    What characterizes an ideal gas in the context of the Brayton cycle?

    <p>It exhibits constant properties throughout the cycle</p> Signup and view all the answers

    What does the power output of the Brayton cycle depend on?

    <p>The temperature differences and specific heat at constant pressure</p> Signup and view all the answers

    What is the main purpose of a gas-to-gas heat exchanger in the Brayton cycle?

    <p>To recover waste heat for preheating entering air</p> Signup and view all the answers

    In the equation for heat input, what does $Q_{in}$ represent?

    <p>The heat added to the working fluid during combustion</p> Signup and view all the answers

    What is the primary purpose of a deaerator in energy systems?

    <p>Remove dissolved gases to avoid corrosion</p> Signup and view all the answers

    Which cycles are commonly combined in a combined cycle power plant?

    <p>Brayton Cycle and Rankine Cycle</p> Signup and view all the answers

    What is a significant benefit of the heat recovery steam generator (HRSG) in combined cycles?

    <p>It increases overall efficiency by utilizing waste heat</p> Signup and view all the answers

    In cogeneration plants, what is the average price of self-generated electricity compared to grid electricity?

    <p>About 57% of grid price</p> Signup and view all the answers

    What trend is observed in the demand for self-generated electricity in the chemical process industry?

    <p>Significant increase at 21.3% per year</p> Signup and view all the answers

    What type of cycle uses heat rejection from one cycle to improve another in combined cycles?

    <p>Topping-Bottoming Cycle</p> Signup and view all the answers

    What does the efficiency formula $ ext{η}_{CC} = η_T + η_B - η_Tη_B$ represent?

    <p>Overall efficiency of a combined cycle</p> Signup and view all the answers

    What is the significance of the average temperature values in thermodynamic cycles?

    <p>They influence thermal efficiency</p> Signup and view all the answers

    How does cogeneration benefit industrial processes?

    <p>It permits self-generation of electricity, lowering costs.</p> Signup and view all the answers

    Which of the following options best describes the trend in purchased electricity in the cogeneration sector?

    <p>Experiencing a slight decline</p> Signup and view all the answers

    What is the primary purpose of the National Solar Thermal Power Testing Facility?

    <p>To create a simulation for solar thermal technologies</p> Signup and view all the answers

    What key aspect does the cogeneration system evaluate when heat/power loads are small?

    <p>Feasibility for a group of industries</p> Signup and view all the answers

    In an electric power station setup with cogeneration, which output is crucial for assessing performance?

    <p>The ratio of electricity to heat output</p> Signup and view all the answers

    Study Notes

    Topic 6: Electrical Systems

    • Topics Covered: Power system, Power Plants, Electricity Tariff, Power Factor, Power Generation, Gas Turbine Cycle, Steam Turbine Cycle, Combined Cycle and Cogeneration, Solar Thermal

    • Lectures: Sept 23, 24, 26, 30, Oct 1, 3, 7, 8, 10, 14, 15

    Power System

    • System Load: Time intervals (daily, weekly, seasonal, annual), Usage (residential, industrial, commercial, agricultural), End-usage (lighting, air conditioning, pumping, etc.)

    Load Curve

    • Graphical Representation: A visual representation of electrical load (power) over time
    • Energy Requirement: The area under the load curve indicates the energy needed
    • Importance: Crucial for plant operation (preparation, shut-down, coordination, etc.)

    Typical Load Curves

    • Various examples of load curves are shown
      • Industrial plant with single shift
      • Commercial shops
      • Street Lighting
      • Urban load curve

    Understand Load Curve

    • Peak Load: Maximum demand (growth and capacity addition) = important factor for investment.
    • Average Load: Total energy/time duration, impacts cost

    System Load Factor

    • Definition: Average load/peak load
    • Significance: Important planning objective to increase system load factor

    Capacity Factor

    • Definition: Average load/plant capacity
    • Applications: Total energy produced/maximum possible production, part load operation.
    • Factors: Plant efficiency, operating cost, recovery potential

    Load & Capacity Factors

    • Load and capacity factor always ≤ 1
    • Inadequate utilization of installed capacity
    • Parts load operation of plant
    • Impact on efficiency
    • Impact on increased fuel consumption and higher cost
    • Instability in rapid rate increase of load

    Utilization Factor

    • Definition: Peak load/plant capacity
    • Purpose: Shows the extent to which plant capacity is used to meet the peak demand, important in power system planning
    • Importance: Reliability of power system and capacity addition planning

    Connected Load & Diversity Factor

    • Connected Load: Sum of equipment ratings.
    • Demand Factor: Peak load/connected load
    • Diversity Factor: Sum of individual peak load/actual peak load; important for load factor improvement; inverse of diversity factor equates to coincidence factor

    Power Plants: Dispatchability

    • Dispatchable: Coal, natural gas, nuclear power plants (can generate and dispatch power on demand)
    • Non-Dispatchable: Wind, solar (no control over generation/dispatch)
    • Peak Load: Plants used intermittently (low operating costs).
    • Base Load: Plants operating continuously (high capital costs)
    • Intermediate: Plants with moderate capital and operating costs

    Non-Dispatchable Power Plants

    • Characteristics: Variable power (solar, wind).
    • Factors: Production varies with resource and has low capacity factor, high capital cost.

    Electricity Tariff

    • Components: Maximum demand charges, Energy charges, power factor penalty/bonus rates, fuel cost adjustments, meter rentals, time of day (TOD) charges, surcharges.
    • Details for various consumers: Residential, agricultural, industrial, commercial, public works

    Power Factor

    • Effect: Improves energy efficiency.
    • Importance: Improves energy efficiency and reduces losses.
    • Impact: Penalty for low power factor.

    Basics of Power

    • Power Terms: Active (P), Reactive (Q), Apparent (S) power
    • PF: Power factor, cos(0−ψ), phase angle difference between voltage and current

    Power Generation: Thermal Route

    • Types: Coal, nuclear, biomass, and geothermal are dispatchable.
    • Cycles: Thermodynamics cycles/working fluids

    Gas Turbine Cycle

    • Simple Gas Turbine: Open cycle/combustion turbine
    • Analysis: Closed loop approximations/Brayton cycle (isentropic and constant-pressure heat transfer)
    • Components: Compressor, combustion chamber, turbine.
    • Assumptions: Air as working fluid; closed-loop cycle, constant properties of air.

    Ideal Brayton Cycle

    • Equations: Energy balance (Qin, Qout), temperature-pressure relationships
    • Efficiency and Power: Calculations relate efficiency and power outputs to various inputs.
    • Importance: Illustrates an ideal model for comparison with real-world systems.

    Brayton Cycle: Modifications

    • Intercooling: Cooling the compressed air between compressor stages
    • Reheating: Heating the combusted gas between turbine stages
    • Regeneration: Recovery of heat from the turbine exit to raise the temperature of the combustion air

    Brayton Cycle: Non-idealities

    • Turbine/Compressor Efficiency: Account for actual work versus ideal work.
    • Pressure Drop: Consideration for pressure loss through different components.

    Steam Turbine Cycle

    • Rankine Cycle: Two isentropic work steps and two constant pressure heat steps; different working fluid than Brayton cycle
    • Modified Carnot Cycle: Addressing two-phase fluid condensation, liquid droplet formation, and superheating the vapor.
    • Additional Considerations: Superheating, deaerator effects, steam extraction and feed water heating/reheating, pressure ratios, dryness fractions.

    Reheat Cycle

    • Reheater: Employed between turbines, improving efficiency by increasing the heat input to the turbine (3-4 percentage point improvement).
    • Optimal Pressure Ratio: Factors of 0.2 - 0.3

    Regeneration Cycle

    • Feed Water Heating: Steam extracted from turbines to preheat the feed water, enhancing cycle efficiency.
    • Improvements: 7 - 13 feed heaters, 10 - 13% efficiency improvement.

    Deaerator

    • Purpose: Removes dissolved gases to avoid corrosion.
    • Function: Heating, separation, and removal of dissolved gases to protect plant components.

    Combined Cycle

    • Multi-cycle Approach: Combines Brayton and Rankine cycles to produce more efficient power plants.
    • Advantages: High efficiency, increased power output, potentially reduced cost.

    Cogeneration

    • Heat integration: Combined heat and power generation
    • Use cases: Appropriate for situations with significant heat demand
    • Industrial Application: Suitable for chemical, manufacturing facilities.

    Solar Thermal/PV

    • Solar Thermal: National thermal power plant testing.

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    T6 Electrical Systems 2024 PDF

    Description

    Test your knowledge on electrical systems covering power systems, load curves, and power generation methods. This quiz includes key concepts such as electricity tariffs, power factors, and different turbine cycles. Assess your understanding of how electrical loads are represented and managed over time.

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