power satm lab

7/28/2019 Power Satm Lab

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*3840EP* (Pages : 16) 3840 (E) P

Seventh Semester B.Tech. Degree Examination, July 2009

Electrical and Electronics Engg.

POWER SYSTEMS LABORATORY

Time : 3 Hours Max. Marks : 100

1. a) For the given three bus system, obtain the line flows by

i) Gauss Siedel Method with an acceleration factor of 1.6 and

ii) Newton-Raphson method.

Comment on the results obtained. All the data are in p.u. on 100 MVA base.

Assume Q limits of generator 2 as-100 MVAR and 300 MVAR.

Line CodeAdmittance

Ypq

Line charging

Y'pq/2

1 - 2 1.47-j 5.88 j 0.15

1 - 3 2.94-j 11.77 j 0.07

2 - 3 2.75-j 9.17 j 0.04

Specified Generation Load

Voltage p.u. MW MVAR MW MVAR

1.04 -- -- 0.0 0.0

1.02 100.0 -- 50.0 20.0

-- 0.0 0.0 250.0 150.0

b) i) Measure the earth resistance of the given earthing system.

ii) Measure the soil resistivity of the given area.

Reg. No. : .....................................

Name : ..........................................

P.T.O.


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2. a) For the given three bus system, obtain the line flows by

i) Gauss-Siedel Method with an acceleration factor of 1.4 and

ii) Fast Decoupled method.

Comment on the results obtained. All the data are in p.u. on 100 MVA base.

Assume the limits of reactive power for generator 2 as-100 MVAR and

100 MVAR.

Line Code AdmittanceYpq

Line chargingY'pq/2

1 - 2 1.47-j 5.88 j 0.15

1 - 3 2.94-j 11.77 j 0.07

2 - 3 2.75-j 9.17 j 0.04



1.02 -- -- 0.0 0.0

1.00 100.0 -- 100.0 40.0

-- 0.0 0.0 200.0 100.0

b) i) Conduct the megger test on the given electric motor. Comment on the results.

ii) Find the polarization index of the given LT transformer.


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3. a) For the given six bus system, run load flow using Gauss-Siedel method and

obtain the change in line flows when the generation at bus number 2 is reduced

by 50%. Base MVA = 100 and Voltage = 11 kV.

Line Code Resistance p.u. Reactance p.u.

1 - 4 0.057 0.0845

1 - 5 0.0133 0.036

2 - 3 0.032 0.0175

2 - 5 0.0173 0.056

2 - 6 0.03 0.15

4 - 5 0.0194 0.0625

Bus Specified Generation in p.u. Load in p.u.

Code Voltage p.u. pu pu pu pu

1 1.05 + j 0.0 -- -- -- --

2 -- 1.2 0.05 -- --

3 -- 1.2 0.05 -- --

4 -- -- -- 1.4 0.05

5 -- -- -- 0.8 0.03

6 -- -- -- 0.7 0.02

b) Determine the power factor of the given Induction Motor while delivering rated

output. Design a capacitor bank which will improve the power factor of the

motor to unity at the same loading condition. Also determine the changes taking

place in line current and power factor experimentally.


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4. a) Obtain the fault MVA when a three phase to ground fault occurs at

i) Bus no. 4 and

ii) line 1-3 at 60% distance from 3. The transmission lines have uniform resistance

of 5 ohms and reactance of 20 ohms. The transformer is rated :

5000 kVA, 11/33 kV and reactance 6 ohms. The details of two generators are :

G1-10,000kVA, 11kV, Xd = 10%. G2-5000 kVA, 11kV, Xd = 7.5%.

b) Determine the Time Dial setting required for the given over current relay

(electromechanical) so as to obtain a delayed operation of 1.5 seconds in thefollowing condition. Current setting 2.5A, Current Transformer ratio 1000/5,

Fault current 5000 A test and verify the results.

5. a) Obtain the fault current and fault MVA for the given four bus system. The faultdetails are

i) Single line to ground at each line

ii) Double line to ground fault and

iii) Three phase fault for each generator. Base MVA = 10 and generator

voltage = 6.6 kV.

Line No. Reactance (ohms)

1 - 3 1.0

2 - 4 0.57

1 - 2 1.5

3 - 4 0.3

1 - 4 1.2

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Bus No. Reactance (Xd' p.u.)

1 10%

2 7.5%

3 7.5%

4 10%

b) Measure the power consumed by a load of 1500 VA 0.8 pf lag using the givenCT and PT and find the error in measurement.

6. a) Obtain a contingency rank list based on the voltage profile for the given four bus

system. The transmission lines have uniform resistance of 5 ohms and reactance

of 20 ohms. The transformer is rated : 5000 kVA, 11/33 kV and reactance

6 ohms. The details of two generators are : G1-10,000 kVA, 11 kV, Xd = 10%.

G2-5000 kVA, 11kV, Xd = 7.5%. The load at bus 4 is 10 MW at 0.8 pf lag. The

generator and transformers are star grounded.

b) Test the given 11 kV AB Switch and 11 kV Pin Insulator for power frequency

withstand voltage.

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7. a) Determine the fault currents contributed by the generators for a three phase to

ground fault occurring at

i) bus number 3 and ii) bus number 4.

Compare and justify the results. The two generators are rated 11kV, 100 MVA

and transient reactance of 10%. The two transformers are rated 11/110 kV,

100 MVA and leakage reactance of 5%. They are /Y.

Line No. Impedance in p.u.

3 - 4 0.0 + j 0.2

1 - 3 0.0 + j 0.15

1 - 4 0.0 + j 0.1

2 - 3 0.0 + j 0.2

2 - 4 0.0 + j 0.15

b) i) Determine the dielectric strength of the given sample of transformer oil and

comment on the result.

ii) Determine the dielectric strength of the given solid dielectric material.

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8. a) For the given three bus system, using Newton Raphson find the change in

voltage at bus numbers 2 and 3 when the generator at bus 2 is removed. All thedata are in p.u. on 100 MVA base.

Line CodeAdmittance

Ypq

Line charging

Y'pq/2

1 - 2 1.47-j 5.88 j 0.15

1 - 3 2.94-j 11.77 j 0.07

2 - 3 2.75-j 9.17 j 0.04



1.02 -- -- 0.0 0.0

1.00 100.0 -- 100.0 100.0

-- 0.0 0.0 200.0 100.0

b) Design a capacitor bank for the given induction motor for obtaining maximum

saving in the electricity bill which is calculated on the basis of KVA maximum

demand and energy consumed. Determine experimentally the KVA saved when

it delivers 50% rated output.

9. a) For the given six bus system, run load flow using Gauss Siedel method and

obtain the change in line flows in elements 1 and 6 when the load at bus number

4 is reduced by 50%. Base MVA = 100 and Voltage = 11kV.

Line CodeResistance

p.u.

Reactance

p.u.

14 0.057 0.0845

15 0.0133 0.036

23 0.032 0.0175

25 0.0173 0.056

2

6 0.03 0.1545 0.0194 0.0625

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Bus

Code

Specified

Voltage p.u.Generation in p.u. Load in p.u.

pu pu pu pu

1 1.05 + j 0.0

2 1.2 0.05

3 1.2 0.05

4 1.4 0.05

5 0.8 0.03

6 0.7 0.02

b) Find the specifications of the given static relay required to trip at 2.5 seconds at

a fault current of 400 A. The CT ratio is 200/5.

10. a) For the given six bus system, run load flow using Newton Raphson method andobtain the change in voltage at bus 4 when the load at bus number 4 is changed

in steps of 0.5 p.u. and plot the PV curve. Base MVA = 100 and Voltage = 11 kV.

Line CodeResistance

p.u.

Reactance

p.u.

14 0.057 0.0845

15 0.0133 0.036

23 0.032 0.0175

25 0.0173 0.056

26 0.03 0.15

45 0.0194 0.0625

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BusCode

SpecifiedVoltage p.u.

Generation in p.u. Load in p.u.

pu pu pu pu

1 1.05 + j 0.0

2 1.2 0.05

3 1.2 0.05

4 1.4 0.05

5 0.8 0.03

6 0.7 0.02

b) Apply the following settings for the given over current relay (static) and test it.

Current setting Is-2.5A, IHS 20 A, Time Multiplier Setting 0.5 and Curve SI

11. a) For the given five bus system, run load flow using Fast Decoupled method and

obtain the change in line flows in elements 1 and 3 when an additional generator

delivering 120 MW at a specified voltage of 1.02 is placed at bus number 5.

Base MVA = 100 and Voltage = 138 kV.

Line CodeResistance

p.u.

Reactance

p.u.

Line

Charging

12 0.042 0.168 4.1

15 0.031 0.126 3.1

23 0.031 0.126 3.1

34 0.084 0.336 8.2

35 0.053 0.210 5.1

45 0.063 0.252 6.1

*3840EP* -9- 3840 (E) P


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Bus

Code

Specified

Voltage p.u.Generation Load

MW MVAR MW MVAR

1 1.04 + j 0.0 65 30

2 1.00 + j 0.0 115 60

3 1.02 + j 0.0 180 70 40

4 1.00 + j 0.0 70 30

5 1.00 + j 0.0 85 40

b) Calibrate the given HV peak Voltmeter using sphere gap.

12. a) An isolated power system has the following parameters :

Turbine time constant = 0.5 sec.

Governer time constant = 0.3 sec.

Generator inertia constant = 6 sec.

Governer speed regulation = 0.04

Frequency deviation factor of the load = 0.8

Create the Simulink model for the above system. Determine the variation in

frequency corresponding to a load disturbance of i) 0.2 p.u. ii) 0.3 p.u. and

iii) 0.1 p.u. Modify the same system to reduce the steady state error.

b) i) Determine the dielectric strength of the given sample of transformer oil.

ii) Determine the dry impulse flash over voltage of the given disc insulator.

13. a) An interconnected power system has the following parameters :

Area 1 Area 2

Turbine time constant 0.3 sec 0.25 sec

Governer time constant 0.1 sec 0.15 sec

Generator inertia constant 0.0833 0.0833

Governer speed regulation 2.4 Hz/pu 2.4 Hz/pu

Frequency deviation factor of the load 0.00833 pu 0.00833

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Create the Simulink model for the above system. Synchronising constant is

0.545.Determine the response in frequency deviation corresponding to a loaddisturbance of i) 0.2 p.u. and ii) 0.3 p.u. in area 1.

b) i) Measure the earth resistance of the given earth electrode using the mostaccurate method.

ii) Determine the insulation resistance of the given energy meter.

14. a) For the given five bus system, run load flow using Newton Raphson methodand obtain the change in line flows in elements 1 and 3 when an additionalgenerator delivering 120 MW at a specified voltage of 1.02 is placed at bus

number 2. Base MVA = 100 and Voltage = 138 kV.

Line CodeResistance

p.u.

Reactance

p.u.

Line

Charging

12 0.042 0.168 4.1

15 0.031 0.126 3.1

23 0.031 0.126 3.1

34 0.084 0.336 8.2

35 0.053 0.210 5.1

45 0.063 0.252 6.1

Bus

Code

Specified

Voltage p.u.Generation Load

MW MVAR MW MVAR1 1.04 + j 0.0 65 30

2 1.00 + j 0.0 115 60

3 1.02 + j 0.0 180 70 40

4 1.00 + j 0.0 70 30

5 1.00 + j 0.0 85 40

b) i) Megger the given transformer and comment on the result.ii) Find the insulation resistance of the given LT cable.

*3840EP* -11- 3840 (E) P


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15. a) For the given five bus system, run load flow using i) Fast Decoupled method

ii) Newton Raphson method and iii) Gauss Siedel method and obtain the changein line flows in all elements when the load at bus number 5 is removed.

Base MVA = 100 and Voltage = 138 kV

Line CodeResistance

p.u.

Reactance

p.u.

Line

Charging

12 0.042 0.168 4.1

15 0.031 0.126 3.1

23 0.031 0.126 3.1

34 0.084 0.336 8.2

35 0.053 0.210 5.1

45 0.063 0.252 6.1

Bus

Code

Specified

Voltage p.u.

Generation Load

MW MVAR MW MVAR

1 1.04+j0.0 -- -- 65 30

2 1.00+j0.0 -- -- 115 60

3 1.02+j0.0 180 -- 70 40

4 1.00+j0.0 -- -- 70 30

5 1.00+j0.0 -- -- 85 40

b) Design a capacitor bank for the given Induction Motor in order to improve the

power factor from 0.8 to unity. Obtain the performance characteristics with

and without capacitor (i) Output with line current and (ii) Output with power

factor.

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16. a) For the given five bus system, run load flow using Newton Raphson method

and obtain the change in line flows in all elements when an additional generatordelivering 80 MW at a specified voltage of 1.02 is placed at bus number 4.

Base MVA=100 and Voltage = 220 kV.

Line Code Impedance p.u.Line Charging

Y' pq/2

1-2 0.02+j0.06 0.0+j0.03

1-3 0.08+j0.24 0.0+j0.025

2-3 0.06+j0.18 0.0+j0.020

2-4 0.06+j0.18 0.0+j0.020

2-5 0.04+j0.12 0.0+j0.015

3-4 0.01+j0.03 0.0+j0.010

4-5 0.08+j0.24 0.0+j0.025

Bus

Code

Specified

Voltage p.u.

Generation Load

MW MVAR MW MVAR

1 1.06+j0.0 -- -- 0.0 0.0

2 1.00+j0.0 40 30 20 10

3 1.00+j0.0 -- -- 45 15

4 1.00+j0.0 -- -- 40 55 1.00+j0.0 -- -- 60 10

b) Determine the pickup and D/O current of the given over current relay (static)

which has been set at 2.5 A. Also determine the operating time at TMS = 0.6,

Plug setting multiplier = 10.

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17. a) For the given five bus system, run load flow using Newton Raphson methodand obtain the change in line flows in all elements when the generator at bus

number 2 is removed. Base MVA = 100 and Voltage = 220 kV.

Line Code Impedance p.u.Line Charging

Y' pq/2

1-2 0.02+j0.06 0.0+j0.03

1-3 0.08+j0.24 0.0+j0.025

2-3 0.06+j0.18 0.0+j0.020

2-4 0.06+j0.18 0.0+j0.020

2-5 0.04+j0.12 0.0+j0.015

3-4 0.01+j0.03 0.0+j0.010

4-5 0.08+j0.24 0.0+j0.025

Bus

Code

Specified

Voltage p.u.

Generation Load

MW MVAR MW MVAR

1 1.06+j0.0 -- -- 0.0 0.0

2 1.00+j0.0 40 30 20 10

3 1.00+j0.0 -- -- 45 15

4 1.00+j0.0 -- -- 40 5

5 1.00+j0.0 -- -- 60 10

b) i) Measure the soil resistivity of the given area and suggest a suitable earthing

method for a 110 KV substation.

ii) Determine the dielectric strength of air using sphere gap.

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18. a) An isolated power system has the following parameters

Turbine time constant = 0.6 sec.

Governer time constant = 0.2 sec.



Frequency deviation factor of the load = 0.7.Create the Simulink model for the above system. Determine the variation in

frequency corresponding to a load disturbance of i) 0.2 p.u. ii) 0.3 p.u. and

iii) 0.1 p.u. with and without supplementary control of i) K= 2 and ii) K= 5.

Find the response when the governor time constant is increased to 0.5 sec.

b) i) Megger the given four core cable and comment on the results.

ii) Conduct HV test on 11 KV lightning arrester ?

19. a) Obtain the fault currents when there is a single line to ground fault at the midpoint

of the transmission line 100 kms long and 0.848 ohms per km in the given four

bus system. The generators are rated with 21 MVA, 13.8 kV and Xd, of 30%.

The transformers have 7 MVA, 13.8/66 kV and Xd of 8.4% ratings. How much

is the difference when there is a double line to ground fault at the same point.

b) Obtain the power frequency withstand voltage and flashover voltage of the given

11 kV suspension insulator.

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20. a) An isolated power system has the following parameters :

Turbine time constant = 0.5 sec.Governer time constant = 0.3 sec.



Frequency deviation factor of the load = 0.8

Create the Simulink model for the above system. Determine the variation infrequency corresponding to a load disturbance of i) 0.2 p.u. ii) 0.3 p.u. and

iii) 0.1 p.u. Modify the same system to reduce the steady state error.

b) i) Measure the earth resistance of the given earthing system.ii) Measure the soil resistivity of the given area.

21. a) Obtain the fault currents and fault MVA for i) single line to ground fault at busnumber 3 ii) double line fault at line 1 5 and iii) double line to ground fault at

bus number 5, for the given system. All data are on 100 MVA base.

Line CodeImpedance

p.u.

Line Charging

Y' pq/2

45 0.018 + j 0.11 0.0 + j 0.113

51 0.004 + j 0.0235 0.0 + j 0.098

41 0.007 + j 0.04 0.0 + j 0.041

Transformer Details

BusImpedance

p.u.Voltage ratio

24 0.022 220/25 kV

35 0.04 220/20 kV

Generator Details

Bus X'd p.u. Voltage

2 0.067 25 kV

3 0.10 20 kV

b) Apply the following settings for the given earth fault relay (static) and test it.

Current setting Is 1A, IHS 5A, Time Multiplier Setting 0.5 and Curve SI

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power satm lab

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