📘 Power Systems – Question Bank (Page 8)
🔹 Section A: Conceptual Questions (Economic Dispatch)
Q1. What is Economic Dispatch?Economic Dispatch determines optimal power output of generators to minimize total generation cost while meeting load demand.
Q2. What is incremental cost?Incremental cost is the rate of change of fuel cost with respect to power output.
Q3. What is the condition for economic dispatch (without losses)?Incremental cost of all generators must be equal.
dC1/dP1 = dC2/dP2 = λ
Q4. What is penalty factor?Used when transmission losses are considered.
🔹 Section B: MCQs
Q5. Economic dispatch minimizes:A) Voltage
B) Current
C) Fuel cost
D) Frequency
Answer: C) Fuel cost
Q6. For economic dispatch without losses:A) P1 = P2
B) dC1/dP1 = dC2/dP2
C) C1 = C2
D) Voltage equal
Answer: B) dC1/dP1 = dC2/dP2
Q7. Lambda (λ) represents:A) Voltage
B) Frequency
C) Incremental cost
D) Power factor
Answer: C) Incremental cost
🔹 Section C: Numerical Problems
Q8. Two generators have cost functions:C1 = 0.01P1² + 2P1 C2 = 0.02P2² + 1.5P2
Total Load = 150 MWFind economic load sharing (without losses).
Incremental costs: dC1/dP1 = 0.02P1 + 2 dC2/dP2 = 0.04P2 + 1.5 Set equal: 0.02P1 + 2 = 0.04P2 + 1.5 P1 + P2 = 150 Solve equations: 0.02P1 - 0.04P2 = -0.5 Multiply by 50: P1 - 2P2 = -25 Substitute P1 = 150 - P2: 150 - P2 - 2P2 = -25 150 - 3P2 = -25 3P2 = 175 P2 = 58.33 MW P1 = 91.67 MW
Q9. If incremental cost λ = 10 and cost curve slope is 0.02P + 5, find P.
0.02P + 5 = 10 0.02P = 5 P = 250 MW
Q10. Why generators do not share load equally?
Because cost characteristics are different.
🔹 Section D: Important Points
- Equal incremental cost → Minimum total cost
- Losses increase total generation
- Penalty factor modifies incremental cost
- Lambda iteration method is commonly used
Page 8 Completed – Economic Dispatch
.png)
No comments:
Post a Comment