EE6501
Power system analysis,
Third
year, Department of Electrical and Electronics Engineering, Model Exam
Questions.
Answer ALL Questions
Part A (5 x 2 = 10 Marks)
1.
What
is single line diagram?
2.
Define
per unit value
4.
When
it generated bus treated as load bus?
5.
What
is Jacobian matrix?
6.
What
is direct axis reactance?
7.
What
is a slack bus?
8.
What
is the sequence operator?
9.
How
is the power system stability classified?
10. Write the power angle equation?
PartB(5x16=80 Marks)
11. (a) Draw the reactance diagram for the power
system shown in Fig.1. Neglect resistance & use a base of 50 MVA & 13.8
KV on generator G1.
Determine the new value of per
unit reactance of G1, T1, Transmission line 1, Transmission line 2,
G2, T2, G3 and T3
Or
(b) Form Ybus of the
test system shown in Fig.2 using singular transformation method. The impedance
data is given in Table 1. Take (1) as reference node
12. (a) The system data for a load
flow solution are given in Table 2 and 3. Determine the voltages at the end of
the first iteration using the Gauss Seidel method. Take 1=1.6
Table
2: line admittances
Bus
code
|
Admittance
|
1-2
|
2-j8.0
|
1-3
|
1-j4.0
|
2-3
|
0.666-j2.664
|
2-4
|
1-j4.0
|
3-4
|
2-j8.0
|
Table
3: Schedule of active and reactive powers
Bus code
|
P in p.u
|
Q in p.u
|
V in p.u
|
Remarks
|
1
|
-
|
-
|
1.06
|
Slack
|
2
|
0.5
|
0.2
|
1+j0.0
|
PQ
|
3
|
0.4
|
0.3
|
1+j0.0
|
PQ
|
4
|
0.3
|
0.1
|
1+j0.0
|
PQ
|
Or
(b) Draw and explain the step by step
procedure of load flow solution for the Gauss Seidel
method when PV buses are present
13. (a) Generator G1 and G2
are identical and rated 11 kv, 20MVA and have a transient reactance of 0.25 p.u
at own MVA base. The transformer T1 and T2 are also
identical and are rated 11/66 kv, 5 MVA and have a reactance of 0.06 p.u to
their own MVA base. A 50 km long transmission line is connected between the two
generators. Calculate three phase fault current, when fault occurs at middle of
the line as shown in Fig. (16)
Or
(b) Explain symmetrical fault
analysis using Z-bus matrix with neat flow chart (16)
14.
(a)
Derive the expression for the three phase power in terms of symmetrical
components. (16)
Or
(b) A 30 MVA, 11KV, three phase
synchronous generator has a direct sub transient reactance of 0.25 p.u. The
negative and zero sequence reactance are 0.35 and 0.1 p.u respectively. The
neutral of the generator is solidly grounded. Determine the sub transient
current in the generator and the line to line voltages for sub transient
conditions when a single line to ground fault occurs at the generator terminals
with the generator operating unloaded at rated voltage. (16)
15. (a) Derive the expression for
swing equation. (16)
Or
(b) Derive the expression for the
critical clearing angle and clearing time (16)
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