Transmission Line Performance Engineering Assignment (Essay Sample)

NAME:
LECTURER:
UNIT TITLE:POWER SYSTEMS 1
LAB TITLE:TRANSMISSION LINE PERFORMANCE
* Introduction.
The performance of a transmission line changes as the loading changes. In particular, for a given load power factor, both the efficiency and the voltage regulation vary as the line loading varies.
* General Objective.
The key objective of conducting this laboratory exercise is to gain a better understanding of the transmission line modelling as well as the effect of the line loading on the receiving-end voltage and reactive power requirement.
The specific objectives include:
* Modeling a simple power system using the Power World Simulator.
* Investigating the impact of various transmission line parameters on the line performance.
* Investigating the effect of line loading on the receiving-end voltage and reactive power requirement.
The figure above shows the single-generator system to be modelled.
THE PROCEDURE OF SIMULATION.
* Model line with all the three parameters set to non-zero.
* Set the sending-end voltage to Vs = 1.0∠0° per unit (p.u) and the load at PR= O MW, QR=0 MVAr.
* Switch to Run Mode.
* Then select Simulation>Reset to flat start.
* Next, select Simulation>Single solution – Full Newton.
* Record values of Ps, Qs, PR, QR, VR, and δ measured with VR as the reference.
* Maintaining the power factor constant at unity, increase PR in steps of 50 MW until the system becomes unstable.
Note values of PMAX for which the system becomes unstable.
* Repeat Steps 3 to 6 for 0.9 load power factor (a). Lagging.
(b). Leading.
* Select Simulation>Reset to Flat Start in Run mode before solving the load flow in each instance that the load is to be changed.
RESULTS FOR THE EXPERIMENT.
The parameters recorded were as follows:
* Real power at receiving-end, PR (Mega-Watts, MW)
* Reactive power at receiving-end, QR (Mega-Voltage Ampheres reactive, MVAr)
* Voltage at the receiving-end, VR (per unit, p.u)
* Load angle at the receiving-end, δ (deg)
* Real power at the sending-end, PS (Mega-Watts, MW)
* Reactive power at the sending-end, QS (Mega-Voltage Ampheres reactive, MVAr)
* The calculated efficiency for each case in percentage, η (%)
* The voltage regulation in percentage, V.R (%)
* Results when the system operates at unity power factor.
PR (MW)

QR (MVAr)

VR (pu)

δ (deg)

PS (MW)

QS (MVAr)

Efficiency
%

Voltage Regulation

0

0

1.01

-0.03

0.07

-14.72

0

-0.9901

50

0

1.00

2.42

50.29

-12.52

99.4233

0

100

0

0.99

4.83

100.85

-6.05

99.1572

1.0101

150

0

0.99

7.31

151.93

4.94

98.7297

1.0101

200

0

0.97

9.87

203.51

20.89

98.2753

3.0928

250

0

0.96

12.54

255.64

42.38

97.7938

4.1667

300

0

0.94

15.37

308.41

70.33

97.2731

6.3830

350

0

0.92

18.42

361.97

106.18

96.6931

8.6957

400

0

0.90

21.81

416.56

152.37

96.0246

11.1111

450

0

0.86

25.75

472.65

213.73

95.2079

16.2791

500

0

0.81

30.81

531.56

302.98

94.0628

23.4568

550

0

0.67

43.16

602.84

551.29

91.2348

49.2537

600 System Blackout

0

0.51

54.23

572.99

781.61

104.7139

96.0784

* Results when the system operates at 0.9 Leading Power Factor.
PR
(MW)

QR (MVAr)

VR (pu)

δ (deg)

PS
(MW)

QS
(MVAr)

Efficiency
%

Voltage Regulation
5

50

-24.220

1.02

-2.48

50.28

-36.33

99.44

-1.9608

100

-48.432

1.03

-4.88

101.02

-53.28

98.99

-2.9126

150

-72.649

1.04

-7.23

152.24

-65.80

98.53

-3.8462

200

-96.865

1.05

-9.57

203.83

-74.02

98.12

-4.7619

250

-121.081

1.06

-11.90

255.86

-78.02

97.71

-5.6604

300

-145.300

1.07

-14.25

308.32

-77.70

97.30

-6.5421

350

-169.513

1.07

-16.62

361.21

-73.04

96.90

-6.5421

400

-193.73

1.07

-19.05

414.56

-63.80

96.49

-6.5421

450

-217.946

1.07

-21.53

468.40

-49.63

96.07

-6.5421

500

-242.162

1.07

-24.12

522.78

-30.04

95.64

-6.5421

550

-236.387

1.04

-27.36

577.86

27.18

95.18

-3.8462

600

-257.877

1.03

-30.45

633.98

65.75

94.64

-2.9126

650

-279.367

1.01

-33.89

690.97

115.55

94.07

-0.99

700

-300.857

0.99

-37.93

749.80

182.17

93.36

1.0101

750 System Blackout

-322.346

0.95

-43.23

811.71

280.09

92.40

5.2632

* Results when the system operates at 0.9 Lagging Power Factor.
PR (MW)

QR (MVAr)

VR (pu)

δ (deg)

PS (MW)

QS (MVAr)

Efficiency

Voltage Regulation

50

24.220

0.98

-2.35

50.24

12.32

99.5223

2.0408

100

48.432

0.95

-4.81

101.08

45.33

98.9315

5.2632

150

72.649

0.92

-7.47

152.66

85.79

98.2576

8.6957

200

96.865

0.88

-10.42

205.21

136.05

97.4611

13.6364

250

121.081

0.83

-13.83

259.16

200.48

96.4655

20.4819

300

145.300

0.76

-18.13

315.65

290.27

95.0420

31.5789

350

169.513

0.65

-24.78

374.95

442.77

93.3458

53.8462

400 System Blackout

193.730

0.55

-30.91

397.15

591.89

100.7176

81.8182

QUESTIONS
From the results obtained in the procedure, draw the following graphs for the 3 load power factors (unity, 0.9 lagging, and 0.9 leading) on the same axis.
* Graph of QS (reactive power at the sending-end) against PR (real...