-----------------

1Ql 1 Q21 Q31 Q4 1 Tota l 1 Name:

Number:

02/06/2014

Power Generation & Distribution

Midterm #2

Assist. Prof Suna Bolat

EMU, Spring2014

Q1. Cross-sectional area is 16 mm 2 and conductor material is copper for the double feeder low voltage grid given in the figure below. Determine the location and magnitude of maximum

voltage drop (Kcu=44,4mfO.mm2) for the nominal voltage of 400 V.

A SOm 100 m SOm 100m 200m B

380V

G) cos

0 t< 0 \ ~ IsAe.", .

t

2.00fV\

·\-5 b ·7.SA

lO

t q .5 ... 2:l ·o%A

_

/

to )C.~5 _ 5.15 200

"S0rA l O=>VV\ ~S·1-1 M 200 IV\. ~I~~;t~---Jr-------~l--------,J------~yf~.

L-Ts .2€> '~1 3~ ·0? 2.1-.68 c-] s

Q3. Calculate the initial short circuit current at the end of the line (A) for the given network.

Sng=6 MVA Sntr= 10 MVA

E/=10% uK=6% 20km A

x' = 0.1 Q/km

R is ignored11 kV 34.5 kV

UI\Lcd t< - to ~ "3.(\~~= -- - \9 .~sJ£..~ \~ S,,;:; \00 b

_~ )< 3~~5 ~ ~ l-./4.n100 to

t I£."-::. I. I x.3Lr .'J va ( /'1 rs- 34:). .14-t2.)

~o .I:-\:r

Q4. A load ' 30 MW active component and 30 MVAr reactive component is drawn from a 10 kV source~~:Ugh an overhead line. Line is 40 km long with a total impedance of z = 3.6 + j 5.2. a. Calculate the compensation power required to increase power factor to 0.957. b. Calculate the capacitance of appropriate capacitor to obtain that power.

40 Iuv\ .=t~ 3J) --tS5 2.. ..Q

1

~(n _ 30 MV4r -::- \(03(11 "> '7 ~l -'t:' « \ 3 L> r'V\vU

coste, :.0 .1-01

0.) Qc.. ~ f' r~4!\ _ktp.J ~3o[t--cx..4-':> -to.." L(..9] ~20 . 0 M\Ar

-4 C6~2.2xlDF

C..I... ::: (, ..b.,., l 0-4 r

! Q1 ! Q2! Q3/ Q4! Total I Name:

Number:

02/06/2014

Power Generation & Distribution

Midterm #2

A SSist. Prof Suno Bolat

EM U, Spring2014

2Q1. Cross-sectional area is 16 mm and conductor material is copper for the double feeder low voltage grid given in the figure below. Determine the location and magnitude of maximum

voltage drop (lCcu=44,4m(O.mm 2) for the nominal voltage of 400 V.

A 50 m 100 m 50m 100m 200 m B

380V 400 V

1 ~.

20 kVA I\.2 cos

c ISO·f ?~O~ x2 3~2..! - $0-3 A q3S1 J

uOO -380 , c:;"'~ 1 ~I f~ ?, - f ::;. .fi x _435:) I ""= leg .

'1 ~ 22 .04 x .:2C:>0 -;:.. 12. fa 260

-1'). ~ 22 .0 Lt x ~So :::. g. lI4 ;\ 350 f

J l·S \

6~x 1& O\-\- 0{ 6UlY\O\x ;::. 5".0b \! f

Q2. For the given single feeder low voltage network; the cross-sectional area is 10 mm 2• Voltage at the pOint "c" IS 231/400 V.

a. Determine the power loss through the entire line. . b. Determine the voltage magnitude at the points "a", "b" and "d".

The line is copper (Kcu=44.4m(O.mm2) and the nominal voltage is 400 V.

231/400 V

TRl a 56 m b 28 c 84 m d

'"' (WI :loA1-"> IfAI ~ 12A 1

lOA 11.07 kW 20 A

cos

«u ",

L;4-'~ ~I~

uJ;:UL-6u(d:::23l-s~22& ~ 226-~~

SU b :: Ul + OUbt. ~2al +.2 ==2~~ ~ 233/403 .

Cl D\ ~ LAc. -4 dlA b~ +6Ul4b ~ 2 31 -f- 2 -+ y. =) 9 :::: ~ 3i .~9 ~ 2 34 .1-~ / q 1/.

0 3. Calculate the initial short circuit current at the end of the line (Al for the given network.

Sng=6 MVA Sntr= 10 MVA

£d"=10% uK=6%

11 kV 34.5 kV

, Xq::: Ed ~ LA" L --

\0 X

100 Si'1j 100

Ul\1. b ~_x~-\-r ~ UI(.

>< 100 $I\~( IOD

'I-- h,,€ -=-:x.' ~ {. := 0.')(.20

X" )

Q4. A load with 30 MW active component and 30 MVAr reactive component is drawn from a 10 kV, 50 Hz source through an overhead line. Line has a total impedance of z =3.6 + j 5.2 O.

a. Calculate the compensation power required to increase power factor to 0.957. b. Calculate the capacitance of appropriate capacitor to obtain that power.

-80 30

(A. . Q(:= P r~1Q • ... -t-CA\ltJ, J ~ 30 [+U)l{lt -tCAf\~ll ~30\~Lt'3"",,-~l\l-b 9J

;