Year 2024

Week # 2 Quiz 5

Q1. Two insulator discs of identical capacitance value \(C\) make up a string for a \(22 kV, 50 Hz\), single phase overhead line insulation system. If pin to earth capacitance is also \(C\), then find the string efficiency.

Q2. A transmission line of 210 km length has certain values of A, B, C, D. If the length is made 100 km, then the parameter

Q3. The positive, negative and zero sequence impedances of a 200 MVA, three-phase, 15 kV, star-grounded, 50 Hz generator are j0.15 pu, j0.1 pu and j0.02 pu respectively on the machine rating base. The machine is unloaded and working at the rated terminal voltage. If the grounding impedance of the generator is j0.01 pu, then the magnitude of fault current for a b-phase to ground fault is __________

Q4. In a string of suspension insulators the shunt capacitance can be decreased by using

Q5. The penalty factor

Q6. With 100% series compensation of lines

Q7. Which supply line has highest current rating?

Q8. Which is correct, when the diversity factor of a plant is increases?

Q9. The characteristic impedance of a transmission line with series impedance Z ohm per unit length and shunt admittance Y mho per unit length is given by

Q10. Four identical alternators each rated for 20 MVA, 11 KV having a sub transient reactance of 16% are working in parallel. The shortcircuit level at the bus bars is