Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 5th Semester (Fifth Semester) 2015-2016 Elements Of Power System Nee 501Eee 503 Question Paper
Printed Pages : 5 564/548 NEE-SO l/EEE-503
(Following ?PaperVID and Roll No. to be ?lled in your
Answer Book)
Paper 11):121501/121523R011No.? | J | | I l
. . B.Tech.
(SEM; V) THEORY EXAMINATION, 2015-16
. ELEMENTS OF POWER SYSTEM
lTime": 3 hours] ' [Total Marks : 100 |
Note ; Attempt all sections.-
Section-A
?3... ? Attempt all parts. All part'carry equal marks.- Write
' answer ofeachlpart in'short. x (2X1f220)
(a) : Discuss,the effect of change in ytemperat! re 0n
lgngth of oyerhcad transmission line. T
l
(b) An ACSR conductor having a diameter of l ? 111 has
an internal inductance equal to 0.05 mH/km. If it
is replaced by another AC SR having a diameter?to
2 cm then calculate its internal inductance. ?.
(c) De?ne Skin effect.
9300 ' ; (1) P.T.O.
(d) '
(e)
(f)
9300
(g)
(h)
(i)
0)
Draw single line diagram of a typical power system.
What are the methods used for equalizihg the
potential across the insulator string in transmission .
lines'. 7
De?ne Criticasl disruptive voltage & Visual
critical voltage.
What is the need of transposition of transmissiOn
lines?
What 1s the need of groundlng the neutral 1n power
system?
Calculate the reactance Of a Icioil suitable for a
33KV, 3-(1) transmission system o? which the
capacitance to earth of each conductor is ?4.5 ,u ? F.
Describe the vibrations of power conductors and '
explain the methods used to damp out these
vibrations?
(2) NEE?SOI/EEE?503
Section-B
Attempt any ?ve questions from this section.
(IOXS=50)
The daily load cycle of a three phase, 33 kV, 10km
transmission line 1s as follows: 2500 kVA for 8 hours
2000 kV A for 9 hours and 1500 kV A for 7 hours.
Determine the most economical cross section 1f the cost
- of line including erection is Rs (7500) + 6000a) per km
where ?a? is the area of each conductor in sq. cm. the
: rate of interest and depreciation is 8 per cent and cost
93 00
of energy is 15 paise per unit. The line is in use for 250
working days a yeai'. The resistance per km and per sq.
em. is 0.173 ohm.
(a) What are ACSR conductors? Explain the advantages V
ofACSR conductors.
1?
(b) A 50 km long transmission line supplies a load of
5MVA, 33kV at O 8 power factor lagging. The
ef?ciency of transmission 1s 90%. Calqulate the
1
volume of conductor aluminum required for the
.line when i
l-q), 2- wire system is used. i _
3- q), 3-wire system is used.
Take the resitivity 0f Aluminium as
2.85X10'8Q?m
(3) _ P.T.O.
, 2.44 m delta spacing, air temperature 2667 degree. .
9300 .
Derive the inductance per phase for a three ph?Se
transposed transmission line. Also clacilate the
inductance for Horizontal & equilateral tringular
con?guration.
DeriveA, B, C and D parameters for Nominal 7! model
of a medium line and draw its pha_sor diagram.
Determine the corona characteristics of a three phase'
160 km long line having conductor diameter 1.036 cm,
having an appropriate barometric pressure of 73. 1 5 cm,
operating voltage 1 10kV at?Hz. Surface irregularity factor
0.85. Assume a value ot?mv = 0.72 dielectric strength of '
air = 21.1 {kY/cm (rms). Disruptive voltage under foul
_ weather = 1).? times fair weather value.
DeriVe eifptession fOr sag and tension in power
conductor Strung between two supports at equal heights
taking intq account wind and we loading. .
What is neptrial grounding? Describe different methods
of neutral grounding. List their advantages and
disadvantageis. '
(4) NEE-SOI/EEE-503
run...
9..
What are the advantages associated with DC.
transmission. Explain different type of DC. links used
for HVDC transmission.
Section-C
Attempt any two questions form this section.
10.
11
9300
(2 X 1 5=30)
(a) Explain the term surge impedance loading (SIL)?
(b) - The A, B, C, D constants of a 3-q) transmission
line _are A =D = 0.936+j0.016, B = 33.5+j13SQ ? -
and C= (-0.9280+j901.223) >< 10~6 mho. The load
at receiving end 15 40 MW 200kV at power factor
of 0 86 langging. Find 6 magnitude of the sending -
, end voltage, current, p wer and voitage regulation.
Assume that the magn .
de of senqing end voltage
remains constant. - 1
1
t
.(a) What are the main requirements 9f the insulating
materials used for cal: les? Derive an expression
for the insulation resistance of a single core metal
l .
sheathed cable. 1
1 i
x 1
i .
(5) 3.1210.
(b)
.12. (a) i
(b)
Each line of a 3-phase system is suspended by a
string of 3. identical insulators of sel fa capacitance
C farad. The shunt capacitance OfCOnnecting metal
work of each insulator is 0.2 C to earth and 0.1 C
to line. Calculate the string ef?ciency of the
system ifa guard ring increases the cyapacit?mcelto
theline of metal work of the lowest insulator to
0.3 C.
Give a comparison of an' Overhead line 'with, ' -
?Ungderground. .cable as a mediumiof power
transmission.
What are V l'ous FACTS controllers? Explain the
operating p Vnciple of any one 0fthem.
What is a b ndle conductor and how does the use _
of bundled onductor reduce corona loss in EHV
line?
(6)'- - NEE?SOI/EEE?503
Aisfsm?i A .m
This post was last modified on 29 January 2020