ELEC4310: Power System Analysis Assignment 1
Transmission Line Characteristics & Line Compensations
Submission due date: 4 pm Friday 21st March 2025

A1 - Transmission line calculation (25 Marks)
Consider a 345kV, 150km, 50Hz three phase transposed overhead lossless transmission line, which
is made up of three phase conductors with configuration shown in Figure 1. The sub-conductor
diameter and GMR is 1.5cm and 1.2cm respectively. Considering a long transmission line, determine
the followings. [Note: Please refer to Lecture 2 Materials to find theories related to calculations]

Figure 1. Line configuration for A1

(1) Phase constant , surge impedance , velocity of propagation , and the wavelength of the
line.[Note: Ideally should be closer to the speed of light ] (8 marks)
(2) The ABCD parameters of the line. (5 marks)
(3) Current, real and reactive power delivered at the sending end, the percent voltage regulation of
the line, and the power factor at the receiving end if the receiving end absorbs 1200 MW (|| =1.0 p. u. , || = 0.95 p. u.). (10 marks)
(4) Load impedance to maintain || = ||. (2 marks)




ES
1 . can I use these formula to find Line components
2
. need to Convert in 150km or not ?
· GMD =
3
DAB : DBc : Don B
18
DAB = DBc = 6 + 82 = low 6m
DcA = 16m C Sm Sm A
3
GMD = 10x10 x 16 = 11 . 7 m
· Ds = 1 .2 Cm = 0 . 012m , d = 0 . 4 m
GMR= 1 .09&3 = 1 , 09" 0 . 012X 0. 03 = 0 . 18145 m
11 . 7
·= NoGM I = 8 . 35x10H/m0 . 18
↳= 8 . 35 * 10-
"
H/km
· aMR= 1 .09" (0 .05) x 0 . 03 = 0 . 16134m
zh Er
= 1 . 3 x 10 " FimC=zZOM W 11 . 7
0 . 16134
2 = 1 . 3x10-8 F/km = 0 . 013 MF/km
· B = W (C = 22x 50 X 0 . 835x103 x0 .03x106 = 0 . 001035 rad/km
0 . 835x/03
·z 0 . 013
x 10-6
= 253. 442
22x50
= 3 . 035x105km/s
0 ,00/03E
· x= V = 6070 km
· For a Long Transmission Line :
[NBy = [cosur Zc
Sink Ul
J 0 . 414& SinhUL CoshUL
· 1 = 150km , zc = 153 . 0452, = 0 . 001035 rad /km
: It's lossless Transmission Line , . a= 0 => V = jB = j0 , 001035
2) = j0 , 00035 x 150 = jo . 15525 rad
· A = D = cosh (1 = cos(0 . 15525) = 0 . 988
B = zcSinhU) = 153 . 04 x jsin (0 . 15525) = 339 . 498
c= sinhul = jic Si (5() = j153 , by Sim (0 . 15525)
c = j0 , 0006
· Vs) = 1 . 04 . U · /VR1 = 0 . 95 P. U ., Pr = 1200MW
· Pr = VR In · Pf
· Assume SB = 100 MVA
[] = [
0, 988
[S98] ITjo ,06
Vs = 0 . 988 Vi + j39 . 498 Ip &S Vs = 1 . 0 pu , VR = 0 . 95 p. U.Is = j0 , 0006VR + 0 . 988 Ir
From D : 1 . 04 . u = 0 . 988x0 . 95 p. n + j39 .498 Ir
0, 0614p. u = >39 . 498 IR
In = 0 . 00155 - 90
·
p. U
· To mantain (Vs) = /VR) , we must chose match-load Impedance
i e . Zu = Za
2c = 253 .%42 => z = 253 . 44 er
· This is because when Z = Ec , there are No Reflections , the voltagesat the
sending end and receiving end are equal , this is known as surge Impedance
Loading (SIL)
P1 PSSE simulation (45 Marks)
Write a brief report for the following questions. You MUST show your graphic results clearly in your
report. Make sure you have indicated the necessary parameters. We will check both your PSSE
screenshots and PSSE *.sav and *.sld files to verify the results. If the results do not match, you will
not get credit for your submission.
Based on the line parameter in A1:
(1) Use PSSE to verify your calculation in A1 (4). [Hint: Consider Surge impedance loading] (10 marks)
(2) For the original uncompensated line in A1 (Assume || = 345 kV), answer the following ques-
tions using PSSE, if the load is 1200 MW at unity power factor:
(a) What is the magnitude of the receiving end voltage? (3 marks)
(b) What can we do to maintain || = 0.98 p. u.? What kind of compensation is needed? What
is the value of the compensation in MVar? Use PSSE to justify your results. (6 marks)
(c) In the original uncompensated network, increase the load, and investigate the maximum real
power that can be delivered to pure resistive load. Validate your results using theoretical cal-
culation and PSSE results. (6 marks)
(d) Design a series compensation scheme in PSSE to enhance the readability of the original un-
compensated line in A1. Explain with justification in relation to P1 (2c). (10 marks)
(3) For the original uncompensated system in A1, if the load is 900 MW at 0.95 power factor lagging.
Design a shunt compensation scheme (valued in MVar) in PSSE to improve the power factor to
above 0.98, while maintain the receiving end voltage within the range of . ..≤ || ≤
. ... (10 marks)
P2 PSSE-Python API investigation (30 Marks)
[Note: Since PSSE Xplore 34 is a 32-bit software version, you need to use a Python version, which
should be a 32-bit version, too. Therefore, using Python 2.7 (32-bit) (default installation with PSSE
Xplore 34) as your default Python IDLE throughout this course is recommended.]

For P2(1), please provide P2_1.py, P2_1.sav, and P2_1.sld. For P2(2), please provide P2_2.py and
P2_2.sav. The functions used in psspy API include and are not limited to: psseinit, newcase_2, case,
save, bus_data_4, branch_data_3, machine_data_2, load_data_5, switched_shunt_data_3,
plant_data_3, fnsl, abusreal, aswshreal.
· B = z = jX D
Y =
2x(A - 1)
②
jX
Vase = 345kV , SBase = 100 MVA) Ziase = Vase ( 1190 .2
2
· From Part Al : B = 139 . 498 , N = 0 , 988
From D :
B = j39 . 498 = jx = 739 . 498
... X = 39 . 498
Xp . u=
a
= 394 = 0 . 0332 P. U.
From Q :
y = 2x(A) = 2x(01988-1 =j0 , 00060
539 . 098
Yase = Ziase = life = 0 , 00084
B = 0, 0006076 => By . u =
%
,000b = 0 .72
z =jX
-
Vs
I
↳ ·
-
& P:K =XP.r .
-
P.n. P= P.U . =
-
... t 1200MyVs , 4. u
Vase = 345kV , SBase = 100 MVA) Ziase =Ve 1902
· Us
, p.r=
use
= = 1 . 0 pe
y = 2xA
2x (0 . 988 - 1)
=j0 , 000607625
539 . 098
Yase = Ziase = life = 0 , 00084
* = 0 . 0003038 = Ep . u = j0 . 36
1200MW
P
, p.u=-Base = 100MUA = 12 . 0 P . U
5 = p + jp = V] =) I =P I = P
Ir =
12-jQ
Us = 0 . 988x0 1 98 0 + j39 .498x0 . 98 8
1 + j0 = 0 - 9682478 +539 .498x
=> Q -1 . 63p=) :. e. It's capacitive compensation
a = 1. 63x100MVA = 163MVA
p =
r
P= VI= = 12 = 0 . 98 = R = 008.
z = R+ jX
-
ja = 12 < 3 1 10h
(1) Build a system with a Python script and run power flow solution to verify your calculation in A1
(4). Save the built case in P2_1.sav by coding in the Python script P2_1.py. After running the script
file P2_1.py, open P2_1.sav with PSSE and develop the network in a slider file P2_1.sld via the Au-
toDraw function in PSSE. Arrange the buses and branches in a readable manner, take a screenshot
and include it in your report. (20 Marks)
(2) Write a Python script P2_2.py to open P2_1.sav from P2(1) and change the load to 900MW at
unity power factor. Add a shunt compensation scheme through Python codes to keep the receiving
end voltage at 1.00. Design a fully automated process to determine and display the MVar value. (10
Marks)
IMPORTANT SUBMISSION INFORMATION
(a) Case files (.sav), the corresponding diagram files (.sld) and Python script files (.py) should be
submitted in order to achieve a valid submission. Each case file should be named appropriately,
with names identical to their corresponding diagram file. For the files to be provided, please read
P1 & P2 requirements detailed below.
(b) All case and diagram files should be compressed into a single zip file, named
‘########_PSSE_files’, where ######## is your 8-digit student number.
(c) Your PSS/E report must be submitted to Blackboard directly in PDF version. The report itself
should NOT be included in the zip file.
(d) Make sure you have answered all the questions.
(e) This report should be no more than 15 pages (one sided only, Times New Roman font size 12,
single line spacing with 2cm margin on all sides). Appendix does not count. You should place tables
and graphs into the body of the report. All figures, tables and codes presented in the report are
counted in the page limit.
(f) Report must include concise summary of results for each section, along with comments and dis-
cussions. It could be as short as one sentence or long as a paragraph.
(g) Place figures as close as possible to where you refer them to in the context.
(h) Keep at least 3 significant figures throughout the hand calculation.

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