B.E / B. Tech.
PRACTICAL END SEMESTER EXAMINATIONS
Seventh Semester
EE8711 POWER SYSTEM SIMULATION LABORATORY
(Regulations 2017)
Time: 3 Hours Answer Any One Question Max.Marks 100
Aim/Principle/Apparatus Tabulation/Circuit/Program Calculation Viva- Record Total
Required/Procedure Drawing & Voce
Results
20 40 20 10 10 100
1 A three phase transposed line has its conductors placed at a distance of 11 m, 11 m & 22 m. The
conductors have a diameter of 3.625cm. Calculate the inductance and capacitance of the transposed
conductors.
(i) Determine the inductance and capacitance per phase per kilometer of the above three lines. (ii)
Verify the results using the MATLAB program.
2 A three-phase transposed line composed of one ACSR, 1,43,000 cmil, 47/7 Bobolink conductor per
phase with flat horizontal spacing of 11m between phases a and b and between phases b and c. The
conductors have a diameter of 3.625 cm and a GMR of 1.439 cm. The line is to be replaced by a
three-conductor bundle of ACSR 477,000-cmil, 26/7 Hawk conductors having the same cross
sectional area of aluminum as the single-conductor line. The conductors have a diameter of 2.1793
cm and a GMR of 0.8839 cm. The new line will also have a flat horizontal configuration, but it is to
be operated at a higher voltage and therefore the phase spacing is increased to 14m as measured
from the center of the bundles. Spacing between the conductors in the bundle is 45 cm.
(i) Determine the inductance and capacitance per phase per kilometer of the above two lines.
(ii) Verify the results using the MATLAB program.
(i) Determine the Y bus matrix for the power system network shown in fig.
(ii) Check the results obtained by using MATLAB
3
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Transmission line Data
4 i. Determine Z bus matrix for the power system network shown in fig.
ii. Check the results obtained using MATLAB
Buses: 6, numbered serially from 1 to 6
Lines: 5, numbered serially from L1 to L5
Transformers: 2, numbered serially as T1 and T2
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Shunt Load: 2, numbered serially as s1 and s2
Base MVA: 100
5 The figure shows the single line diagram of a simple 3 bus power system with generator at bus-1.
The magnitude at bus 1 is adjusted to 1.05pu. The scheduled loads at buses 2 and 3 are marked on
the diagram. Line impedances are marked in p.u. The base value is 100kVA. The line charging
susceptances are neglected. Determine the phasor values of the voltage at the load bus 2 and 3. Find
the slack bus real and reactive power and verify the results using MATLAB
6. Consider the 3 bus system each of the 3 line bus a series impedance of 0.02 + j0.08 p.u and a
total shunt admittance of j0.02 p.u. The specified quantities at the bus are given below.
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(i) Determine the power flow analysis using Newton-Raphson method
(ii) Verify the result using MATLAB program
7 An isolated power system has the following parameter: Turbine rated output 300 MW, Nominal
frequency 50 Hz, Governer speed regulation 2.5 Hz per unit MW, Damping co efficient 0.016 PU
MW / Hz, Inertia constant 5 sec, Turbine time constant 0.5 sec, Governer time constant 0.2 s, Load
change 60 MW, The load varies by 0.8 percent for a 1 percent change in frequency, Determine the
steady state frequency deviation in Hz 28 Format No. DCE/Stud/LM/34/Issue:00/Revision:00
(i) Find the steady state frequency deviation in Hz.
(ii) Use MATLAB to obtain the time domain performance specifications and the
frequency deviation step response.
8 An isolated power system has the following parameter: Turbine rated output 300 MW, Nominal
frequency 50 Hz, Governer speed regulation 2.5 Hz per unit MW, Damping co efficient 0.016 p.u.
MW / Hz, Inertia constant 5 sec, Turbine time constant 0.5 sec, Governer time constant 0.2 sec,
Load change 60 MW, The system is equipped with secondary integral control loop and the integral
controller gain is Kf = 1. Obtain the frequency deviation for a step response
9 A 3-phase transmission line operating at 110 kV and having impedance 5+j20 Ω is connected to the
generating station through 15,000 kVA step-up transformer. Two alternators are connected to the
bus bars. The ratings of the alternator are 10 %, 16 kV and 5MVA, 7.5%, 16kV. Calculate the short
circuit MVA for a symmetrical fault at the load end of transmission line. Take transformer reactance
as 8%. Verify the result using MALAB.
10 A 20 MVA, 11 kV alternator solidly grounded neutral has a sub transient reactance of 0.25 p.u. The
negative and zero sequence reactances are j0.146, ,j0.06 respectively. A single line ground fault
occurs at the terminals of an unloaded generator. Determine the fault currents & line-to-line
voltages. Neglect resistances. Verify the result using MALAB.
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11 Transient stability analysis of a 9-bus, 3-machine, 60 Hz power system with the following system
modeling requirements: I. Classical model for all synchronous machines, models for excitation and
speed governing systems not included.
(i) Simulate a three-phase fault at the end of the line from bus 5 to bus 7 near bus 7 at time
= 0.0 sec. Assume that the fault is cleared successfully by opening the line 5-7 after 5
cycles ( 0.083 sec) . Observe the system for 2.0 seconds
(ii) Determine the critical clearing time by progressively increasing the fault clearing
time
(iii) Verify the result using MATLAB
12 Two power stations A and B are located close together. Station A has four identical generator sets
each rated 100 MVA and having an inertia constant of 9 MJ/MVA whereas the station B has 3 sets
each rated 200 MVA,4 MJ/MVA. Calculate the inertia constant of a single equivalent machine on a
base of 100 MVA. Verify the results using MATLAB.
13 The fuel cost functions for three thermal plants in $/h are given by C1 = 500 + 5.3 P1 + 0.004 P1 2;
P1 in MW C2 = 400 + 5.5 P2 + 0.006 P2 2; P2 in MW C3 = 200 +5.8 P3 + 0.009 P3 2 ; P3 in MW
The total load, PD is 800MW. Neglecting line losses and generator limits, find the optimal dispatch
and the total cost in $/hr by analytical method. Verify the result using MATLAB program
14 The fuel cost functions for three thermal plants in $/h are given by C1 = 500 + 5.3 P1 + 0.004 P1 2 ;
P1 in MW C2 = 400 + 5.5 P2 + 0.006 P2 2 ; P2 in MW C3 = 200 + 5.8 P3 + 0.009 P3 2 ; P3 in MW
The total load , PD is 975MW. The generation limits are: 200 P1 450 MW 150 P2 350 MW
100 P3 225 MW Find the optimal dispatch and the total cost in $/h by analytical method. Verify
the result using MATLAB program.
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15 Two- area system connected by a tie- line has the following parameters on a 1000 MVA common
base.
The units are operating in parallel at the nominal frequency of 60Hz. The synchronizing power
coefficient is computed from the initial operating condition and is given to be Ps = 2 p.u. A load
change of 187.5 MW occurs in area1
(i) Determine the new steady state frequency and the change in the tie-line flow.
(ii) Construct the SIMULINK block diagram and obtain the frequency deviation response for the
condition in part (i).
16 A power plant has three units with the following cost characteristics:
Where PGi’s are in MW. Find the scheduling for a load of 975 MW. Verify the results using
MATLAB
17 The load dynamics of a single area system are Pr=2000 MW; NOL=1000MW;H=5s;f=50Hz; R=4%;
TG=0.08s;TT=0.3s; Assume linear characteristics . The area has governor but not frequency control.
It is subjected to an increase of 20MW. Construct simulink diagram and hence
(i) Determine steady state frequency.
(ii) If speed governor loop was open, what would be the frequency drop?
(iii) Prove frequency is zero if secondary controller is included.
18 A two area system connected by a tie line has the following parameters on a 1000 MVA base.
R1=0.05pu, R2=0.0625pu,D1=0.6, D2=0.9,H1=5,H2=4; Base power1=Base power2=1000MVA,
TG1=0.2s, TG2=0.3s, TT1=0.5s,TT2=0.6s. The units are operating in parallel at the nominal
frequency of 50Hz. The synchronizing power coefficient is 2pu. A load change of 200MW occurs in
area1. Find the new steady state frequency and change in the tie line flow. Construct simulink block
diagram and find deviation in frequency response for the condition mentioned.
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19 A 60Hz synchronous generator having inertia constant H = 5 MJ/MVA and a direct axis transient
reactance Xd 1 = 0.3 per unit is connected to an infinite bus through a purely reactive circuit as
shown in figure. Reactance‟ s are marked on the diagram on a common system base. The generator
is delivering real power Pe = 0.8 per unit and Q = 0.074 per unit to the infinite bus at a voltage of V
= 1 per unit.
(i) A temporary three-phase fault occurs at the sending end of the line at point F. When the
fault is cleared, both lines are intact. Determine the critical clearing angle and the
critical fault clearing time.
(ii) Verify the result using MATLAB program
20 A 60Hz synchronous generator having inertia constant H = 9.94 MJ/MVA and a direct axis transient
reactance Xd 1 = 0.3 per unit is connected to an infinite bus through a purely reactive circuit as
shown in figure. Reactance’s are marked on the diagram on a common system base. The generator is
delivering real power Pe = 0.6 per unit and 0.8 power factor lagging to the infinite bus at a voltage
of V = 1 per unit. The generator is operating in the steady state at δο=16.79° when the input power is
increased by a small amount ∆P=0.2 per unit. The generator excitation and the infinite bus bar
voltage are the same as before E’=1.35 per unit and V=1.0 per unit.
i) Obtain the step response for the rotor angle and the generator frequency.
ii) Obtain the response using MATLAB function.
iii) Obtain a SIMULINK block diagram representation of the state- space model and
stimulate to obtain the response.
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