## Tuesday, 4 August 2015

### EE2351 POWER SYSTEM ANALYSIS ANNA UNIVERSITY QUESTION PAPER, IMPORTANT QUESTIONS, 2 MARKS AND 16 MARKS QUESTIONS FOR EEE DEPARTMENT

EE 2351 POWER SYSTEM ANALYSIS ANNA UNIVERSITY QUESTION PAPER, IMPORTANT QUESTIONS, 2 MARKS AND 16 MARKS QUESTIONS FOR EEE DEPARTMENT

ANNA UNIVERSITY QUESTION PAPER POWER SYSTEM ANALYSIS IMPORTANT QUESTIONS, 2 MARKS AND 16 MARKS QUESTIONS FOR EEE DEPARTMENT

B.E./B.Tech. DEGREE EXAMINATION, APRIL/MAY 2011
Sixth Semester
Electrical and Electronics Engineering
EE 2351 — POWER SYSTEM ANALYSIS
(Regulation 2008)
Time : Three hours Maximum : 100 marks
PART A — (10 × 2 = 20 marks)1. Draw a simple per-phase model for a cylindrical rotor synchronous machine.
2. What are the advantages of per unit system?
3. What is Jacobian matrix?
4. What is a slack bus?
5. Mention the objectives of short circuit analysis.
6. Write down the balanced and unbalanced faults occurring in a power system.
7. What is sequence network?
8. Write the symmetrical components of a three phase system?
9. Define critical clearing angle.
10. Write swing equation.

PART B — (5 × 16 = 80 marks)11. (a) (i) With the help of single line diagram, explain the basic components
of a power system. (8)
(ii) Write detailed notes about the per-phase model of a three phase
transformer. (8)
Or
(b) Draw the impedance diagram for the electric power system shown in
figure 11 (b) showing all impedance in per unit on a 100-MVA base.
Choose 20-kV as the voltage base for generator. The three-phase power
and line-line ratings are given below. (16)
G1 : 90 MVA 20 kV X = 9%
T1 : 80 MVA 20/200 kV X = 16%
T2 : 80 MVA 200/20kV X = 20%
G2 : 90 MVA 18 kV X = 9%
Line : 200 kV X = 120
Load : 200 kV, S = 48 MW + j64Mvar
Fig. 11. (b)
12. (a) With neat flow chart explain the computational procedure for load flow
solution using fast decoupled method when the system contains all types
of buses. (16)
Or
(b) Explain the step by step computational procedure for the Gauss-Seidel
method of load flow studies. (16)
13. (a) Explain symmetrical fault analysis using Z-bus matrix with neat flow
chart. (16)
Or
(b) A 11 kV, 100 MVA alternator having a sub-transient reactance of 0.25 pu
is supplying a 50 MVA motor having a sub-transient reactance of 0.2 pu
through a transmission line. The line reactance is 0.05 pu on a base of
100 MVA. The motor is drawing 40 MW at 0.8 p.f. leading with a
terminal voltage of 10.95 kV when a 3-phase fault occurs at the generator
terminals. Calculate the total current in generator and motor under fault
conditions. (16)
14. (a) What are the assumptions to be made in short circuit studies? Deduce
and thaw the sequence network for a line to line fault at the terminals of
Or
(b) Two 11 kV, 20 MVA, three phase, star connected generators operate in
parallel as shown in Figure 14. (b) ; the positive, negative and zero
sequence reactance’s of each being, respectively, j0.l8, j0.15, j0.10 pu. The
star point of one of the generators is isolated and that of the other is
earthed through a 2.0 ohms resistor. A single line to ground fault occurs
at the terminals of one of the generators.
Estimate
(i) the fault current,
(ii) current in grounding resistor, and
(iii) the voltage across grounding resistor. (16)
Fig. 14. (b)
15. (a) Describe the Runge-Kutta method of solution of swing equation for
multi-machine systems. (16)
Or
(b) Derive an expression for the critical clearing angle and clearing time. (16)