Model Question Paper-I with effect from 2018-19
15EE71
Seventh Semester B.E.(CBCS) Examination
Power System Analysis 2
(Core subject, E&EE)
Time: 3 Hrs Max.Marks: 80
Note: Answer any FIVE full questions, choosing at least ONE question from
each module.
Module-1
1. Define following terms with an example oriented graph, tree co-tree.
(06 Marks)
.Determine the bus admittance matrix using the singular transformations for the
Sample power system with the line data shown in table below. 0 as reference
(05 Marks)
Derive the algorithm for formation of Ybus by assuming mutually coupling between
transmission lines Marks)
OR
2. What is load flow analysis? What are different types of buses considered during
power system load flow? Discuss significance of slack bus in load flow studies.
(06 Marks)
In the power system shown in fig line 1-2 has the series impedance of 0.04+j0.12 pu
with negligible line charging. The generation and load data is given in the table.
Fig
The slack bus voltage is 1+j0.The voltage magnitude at bus is to be maintained at
1.05 pu and the generator at this bus has Q-Generation limits between 0 and 0.5pu.With
1+j0 pu initial voltages at bus 2.determine its voltage at the end of first iteration ,using
the gauss seidel load flow model (06 Marks)
What is primitive Network Explain its significance (04 Marks)
(Page 1 of
USN
Line No. 1 2 3 4 5
Bus-code p-q 0 1 2 3 0 2 0
Impedance pu) 0.8 0.5 0.4 0.5 0.25
Bus No. Type Generation Load
Real Reactive Real Reactive
1 Slack
2 PV 0.3 0.6 0.2
Module-2
3. Compare Gauss Seidel and Newton -Raphson method of load flow analysis
(04Marks)
Draw flow chart of load flow analysis using Newton -Raphson's method in polar coordinate.
(7marks)
Explain any two method of voltage control in power system (05Marks)
OR
4. (a)Deduce fast decoupled load flow model clearly stating all the assumptions made.
(08 Marks)
In a two bus system shown in fig Q4(b).The bus1 is slack bus with V=1 pu and bus
2is a load bus with P=100MW,Q=50MVAr.The line impedance is (0.12+0.12j)pu on a
bus of 100MVA.Using Newton Raphson load flow method compute and d2 upto one
iteration
Module-3
5. Write down the transmission loss formula .Obtain the losses co-efficient formula for a
system consisting of two Generating plants for Supplying several loads through a
transmission line network (08 Marks)
(b)Briefly explain the two state generator model.With usual notatation derive the
expression for availability and unavalibility in terms of failure and repair rate.
(08 Marks)
OR
6. State unit commitment problem .In brief explain dynamic programming method.
(06 Marks)
.Incremental fuel cost in rupees per MWh for the plant consisting of two units are
Assume both units are operating at all the times ,and total load varies room 40 MW to
250 MW and the maximum and minimum loads on each unit are to be 125 and 20 MW
respectively .How will the load shared between two units as the system load varies the
full range? What are the corresponding values of the plant incremental costs?Also find
the saving of fuel of cost in r/hr for the optimal scheduling of a total load of 130MW as
compared to equal distribution of the same load between the two points (10 Marks)
Module-4
7. (a)Explain the problem formulation and solution procedure of optimal scheduling
for hydrothermal plants (09 Marks)
(b)Define reliability.brifiely explain the modes of failure in power system reliability.
(07 Marks)
OR
8. Obtain an expression for i)steady state reliability R& Q ii)General
reliability index (06 Marks)
(b)Define energy management system Explain the three major function that are carried
out in an energy control center of power system security (06 Marks)
brief explain indirect approach of contingency analysis (04 Marks)
Module-5
9. Explain the point by point method of solving the swing equation (08 Marks)
(b)Obtain the generalized algorithmic expression for bus impedance matrix elements
when a link is added to the partial network. Also discuss the special cases
(08 Marks)
OR
10. For the network graph shown in fig determine with node 1 as reference,
using building algorithim.Neglect mutual coupling. Self impedance of elements are
marked on the diagram .Add elements in the order specified.
.
(08 Marks)
(b)Illustrate clearly the steps involved solving swing equation using Runge -Kutta
method for transient analysis
(08 Marks)
(Page 2 of

Consider three bus system .each of three lines has series impedance of 0.02+0.08j pu and a total
shunt impedance of 0.02jpu.The specified quantities at the buses are tabulated below
Bus Real Load
Demand
Reactive
Load
demand
Real power
generation PG
Reactive
power
generation QG
Volatage
specification
1 2 1 V1=1.04+j0
2 0 0 0.5 1 1+j0
3 1.5 0.6 0 V3=1.04