EX-503-A Electrical Power Generation and Economy - Jun 2025 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aMention the difference sources of electrical power generation and discuss their relative merits and demerits.
   How to answer

   • List conventional and non-conventional sources: thermal, hydro, nuclear, solar, wind, biomass, etc.
   • Compare on availability, capital and running cost, reliability.
   • Discuss merits and demerits of each source.
   • Conclude on relative suitability for base and peak loads.
2. 7 Marks
   bSketch the layout of hydroelectric power plant and explain the functions of each component in it.
   How to answer

   • Draw labelled layout of hydroelectric power plant: reservoir, dam, penstock, turbine, generator, etc.
   • Explain function of each component.
   • Briefly describe working from water storage to power generation.
3. 7 Marks
   aDraw a typical layout of a steam plant. Explain the main features of the layout.
   How to answer

   • Draw typical layout of steam/thermal plant: coal handling, boiler, turbine, condenser, feedwater circuit.
   • Label main circuits: fuel, air, steam, cooling water.
   • Explain main features and sequence of energy conversion.
4. 7 Marks
   bWhat are the factors for site selection of a thermal power station?
   How to answer

   • List factors: fuel availability, water supply, load centre distance, land, transport.
   • Explain environmental, geological and cost considerations.
   • Conclude on techno-economic site selection.
5. 7 Marks
   aExplain the principle and working of Solar PV system.
   How to answer

   • Define photovoltaic effect and solar cell structure.
   • Explain working from solar radiation to DC to AC via inverter.
   • Mention components: PV array, charge controller, battery, inverter.
6. 7 Marks
   bDiscuss how electricity is generated from biomass and its advantages.
   How to answer

   • Describe biomass resources and conversion routes: combustion, gasification, anaerobic digestion.
   • Explain steps of electricity generation from biomass.
   • List advantages: renewable, waste utilization, carbon neutral.
7. 7 Marks
   aExplain the Gas turbine power plant with neat sketch.
   How to answer

   • Draw neat sketch: compressor, combustion chamber, gas turbine, generator.
   • Explain working on Brayton cycle.
   • Mention advantages, limitations and applications.
8. 7 Marks
   bExplain the waste disposal in Nuclear Power plant.
   How to answer

   • Classify nuclear waste: low, intermediate, high level.
   • Describe treatment, storage and disposal methods.
   • Explain safety and environmental precautions.
9. 7 Marks
   aWhat is economic load scheduling and how does it help optimize power plant performance?
   How to answer

   • Define economic load scheduling / economic dispatch.
   • Explain incremental cost criterion for optimum sharing.
   • Show how it minimizes fuel cost and improves plant performance.
10. 7 Marks
    bOn the system consisting of two generating plants the incremental costs in rupees per MWh with $P_1$ and $P_2$ in megawatts are $dC_1/dP_1 = 0.15P_1 + 150$, $dC_2/dP_2 = 0.25P_2 + 175$. The system operates on economic dispatch with $P_1 = P_2 = 400$MW and $\partial P_L/\partial P_2 = 0.2$. Find the penalty factor of plant 1.
    How to answer

    • Write incremental costs $dC_1/dP_1 = 0.15P_1+150$, $dC_2/dP_2 = 0.25P_2+175$.
    • Evaluate incremental costs at $P_1=P_2=400$ MW.
    • Use penalty factor $L_1 = 1/(1-\partial P_L/\partial P_1)$ with coordination equation to find $\partial P_L/\partial P_1$ and then $L_1$.
11. 7 Marks
    aWhy load factors and demand factors are always less than one?
    How to answer

    • Define load factor = average load / maximum demand and demand factor = maximum demand / connected load.
    • Explain why numerator is always smaller than denominator.
    • Give practical significance for utilization and plant sizing.
12. 7 Marks
    bThe fuel costs of two-unit plant are given by $C_1 = 50 + 2P_1 + 0.005 P_1^2$; $C_2 = 100 + 2P_2 + 0.01 P_2^2$ where $P_1$ and $P_2$ are in MW. The plant supplies a load of 350 MW. Find the economic load scheduling of the two units and the incremental fuel cost. Neglect losses.
    How to answer

    • Write fuel costs $C_1 = 50+2P_1+0.005P_1^2$, $C_2 = 100+2P_2+0.01P_2^2$.
    • Apply equal incremental cost criterion $dC_1/dP_1 = dC_2/dP_2$ with $P_1+P_2=350$ MW neglecting losses.
    • Solve for $P_1$, $P_2$ and compute incremental fuel cost $\lambda$.
13. 7 Marks
    aDifferentiate between fixed and operating costs of power plants. List the items which constitute the fixed and operating costs.
    How to answer

    • Define fixed costs vs operating/variable costs.
    • List items: capital, depreciation, interest vs fuel, maintenance, labour.
    • Differentiate on dependence on energy generated.
14. 7 Marks
    bDiscuss the different types of tariffs used for charging the consumers of electrical energy.
    How to answer

    • Define tariff and its objectives.
    • Describe types: flat, block, two-part, maximum demand, TOD, power factor tariffs.
    • Discuss suitability for different consumer categories.
15. 14 Marks
    Write short notes (any two)

    1. a)Peak load pricing
    2. b)Magneto-Hydro dynamic system
    3. c)Load forecasting
    4. d)Cogeneration
    How to answer

    • Select any two topics from peak load pricing, MHD, load forecasting, cogeneration.
    • Give definition, principle and key points for each.
    • Mention advantages/applications with neat points.