POWER SYSTEM ANALYSIS JNTU previous years question papers

POWER SYSTEM ANALYSIS JNTU previous years question papers

 Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks

1. Form Ybus for the network by singular transformation: [16]
Element Positive sequence reactance
E-A 0.04
E-B 0.05
A-B 0.04
B-C 0.03
A-D 0.02
C-F 0.07
D-F 0.10

2. Build Zbus for the 3-bus system connection given as: [16]
element bus code impedance
1 1-2 j0.1
2 1-2 j0.25
3 1-3 j0.1
4 2-3 j0.1

3. Explain modeling of transformer, transmission line, loads and generators for a load flow study. And derive general load flow equations. [16]

4. Derive necessary expressions for the off-diagonal and diagonal elements of the submatrices J1 , J2 , J3 and J4 for carrying out a load flow study on power system by using N-R method in Polar form. [16]
2
KVLL(Base)

5. (a) Prove that Base impedance = M V A3-f(Base)
(b) Obtain pu impedance diagram of the power system of figure 5b. Choose base quantities in generagor circuit.
Generator: 20 MVA, 11 KV, X '' = 0.1 pu
Transformer: 25 MVA, 11/33 KV, X = 0.1 pu
Load: 10 MVA, 33 KV, 0.8 pf lag. [16]

6. A balanced 200 V, 3 phase supply feeds balanced resistive load as shown in figure. If the resistance Rbc is disconnected. Determine Ia , Ib and Ic and symmetrical components of Ia , Ib and Ic . [16]

7. (a) Define steady state stability.
(b) Two turbo alternators with ratings given below are connected via a short line.
Machine 1: 4 pole, 50 Hz, 60 MW, 0.8 pf lag.
moment of inertia 30, 000 kg-m2
Machine 2: 2 pole, 50 Hz, 80 MW, 0.85 pf lag.
moment of inertia 10,000 kg-m2 .
Calculate the inertia constant of single equivalent machine on a base of 200 MVA. [16]

8. (a) What are the assumptions made in deriving swing equation.
(b) Explain point by point method of determine swing curve. [6+10]

FEEL USEFUL PLEASE GIVE +1