📘 Power Systems – Question Bank (Page 3)
🔹 Section A: Conceptual Questions (Transmission Line)
Q1. What are the primary parameters of a transmission line?- Resistance (R)
- Inductance (L)
- Capacitance (C)
- Conductance (G)
Due to magnetic field created by current flow.
Q3. What causes Ferranti effect?Capacitance of long transmission line causes receiving end voltage rise under light load.
Q4. What is surge impedance?Z₀ = √(L/C)
Q5. When does corona occur?When electric field intensity exceeds breakdown strength of air.
🔹 Section B: MCQs
Q6. Ferranti effect is significant in:A) Short line
B) Medium line
C) Long line
D) DC line
Answer: C) Long line
Q7. Surge impedance loading (SIL) depends on:A) Resistance
B) Voltage only
C) Surge impedance
D) Current only
Answer: C) Surge impedance
Q8. Corona loss increases with:A) Larger conductor diameter
B) Lower voltage
C) Higher voltage
D) Larger spacing
Answer: C) Higher voltage
Q9. For short transmission line, model considers:A) Only resistance and inductance
B) Capacitance only
C) Conductance only
D) All four parameters
Answer: A) Only resistance and inductance
🔹 Section C: Numerical Problems
Q10. Calculate inductive reactance if L = 2 mH and frequency = 50 Hz.XL = 2Ï€fL = 2 × 3.14 × 50 × 0.002 = 0.628 Ω
Q11. A 200 km long line has capacitance 0.01 μF/km. Find total capacitance.
Total C = 0.01 × 200 = 2 μF
Q12. Surge impedance if L = 1 mH/km and C = 0.01 μF/km.
Z₀ = √(L/C) = √(0.001 / 0.00000001) = √100000 = 316 Ω
Q13. A 220 kV line carries 600 A at unity PF. Find 3-phase power.
P = √3 × V × I = 1.732 × 220000 × 600 = 228.6 MW (approx)
Q14. Corona power loss per phase = 5 kW. Find total 3-phase loss.
Total loss = 3 × 5 = 15 kW
Q15. Receiving end voltage = 230 kV, sending end voltage = 220 kV. Name the effect.
Receiving end voltage higher → Ferranti Effect
Page 3 Completed – Transmission Line Parameters
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