# Sathyabama University Question Papers

# BE Power System Analysis Fifth sem

Answer All the Questions

1. The reactance of a generator designated A is given as 0.25 per

unit based on the generators nameplate rating of 18 kV, 500

MVA. The base for calculations is 20 kV, 100 MVA. Find A on

the new base.

2. What is bus admittance matrix?

3. What is Acceleration factor in GS method?

4. What are the constraints to be satisfied to solve load flow

equations?

5. Name the main differences in representation of power system for

load flow and short circuit studies.

6. Draw the oscillogram of short circuit current when an unloaded

generator is subjected to symmetrical fault, clearly marking

subtransient, transient and steady state regions.

7. What are the works involved in power flow study?

8. Write the load flow equation of Gauss and Gauss-Seidel method.

9. Brief the tariff structure for electrical energy in Tamilnadu.

10. Write the co-ordination equation.

PART – B (5 x 12 = 60)

Answer All the Questions

11. Obtain the per unit impedance (reactance) diagram of the power

system shown in figure.

Generator (3 phase) : 15 MVA, 8.5 kV, X” = 30%

Transformer T1 (3 Phase) : 6600kVA. 10/100 kV, X” = 10%

Transformer T2 (3 Phase) : 6600kVA. 10/100 kV, X” = 10%

Load : 10 MVA, 12.5 kV, 0.8 p.f.lagging.

Transmission line: 100 ohms/phase.

Choose a Common base of 10 MVA. 12.5kV.

(or)

12. Determine the bus admittance matrix of the system whose

reactance diagram is shown in figure. The currents and

admittance are given in p.u. Determine the reduced bus

admittance matrix after eliminating node – 3.

(g) The interrupting capacity in MVA.

17. Describe the equal area criterion for transient stability analysis of

a system.

(or)

18. Mentioning the assumptions clearly and developing necessary

equations, describe the step by step solution of swing bus.

19. The following data were collected from the daily load curves of a

power system during a year:

Load kw Duration hours

15,000 87

12,000 and over 876

10,000 and over 1,752

8,000 and over 2,628

6,000 and over 4,380

4,000 and over 7,000

2,000 and over 8,760

Construct the annual load duration curve and find the load factor

of the system.

(or)

20. Explain about tariff and types of tariff and also explain the types

of consumers and their tariff.