PS Lab Manual

7/23/2019 PS Lab Manual

1/23

PRANVEER SINGH INSTITUTE OF TECHNOLOGY

POWER SYSTEM LAB MANUAL

(EEE 751)

PREPARED BY:- PIYUSH AGNIHOTRIEN DEPARTMENT

PSIT COLLEGE

KANPUR


2/23

I!"#S$N%$ P&'" N%$

I!"# -------------------------------------------------------------------------------

S**&+, --------------------------------------------------------------------------------- .

L/0 % E#2"3/4"0 ----------------------------------------------------------------------------- E#2"3/4"0 N%$ 1 ------------------------------------------------------------------------------ 5

E#2"3/4"0 N%$ --------------------------------------------------------------------------------- 6

E#2"3/4"0 N%$ . ---------------------------------------------------------------------------------1

E#2"3/4"0 N%$ ---------------------------------------------------------------------------------1

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3/23

S**&+,

(A) H&3!&3" B&"!:

1. To determine direct axis reactance (xd) and quadrature axis reactance (xq) of a salient pole

alternator.

2. To determine negative and zero sequence reactances of an alternator.

3. To determine sub transient direct axis reactance (xd) and sub transient quadrature axis

reactance (xq) of an alternator

4. To determine fault current for L!" LL" LL! and LLL faults at t#e terminals of an

alternator at ver$ lo% excitation

&. To stud$ t#e 'T over current rela$ and determine t#e time current c#aracteristics

*. To stud$ percentage differential rela$

+. To stud$ 'mpedance" ,- and eactance t$pe distance rela$s

/. To determine location of fault in a cable using cable fault locator

0. To stud$ ferrant$ effect and voltage distribution in ,.. long transmission line using

transmission line model.

1. To stud$ operation of oil testing set.

(B) S/4,*&0/% B&"! E#2"3/4"0 (,/' MATLAB %3 & %0;"3 %0&3")

11. To determine transmission line performance.

12. To obtain stead$ state" transient and subtransient s#ort circuit currents in an alternator

13. To obtain formation of bus and perform load flo% anal$sis

14. To perform s$mmetrical fault anal$sis in a po%er s$stem

1&. To perform uns$mmetrical fault anal$sis in a po%er s$stem


4/23

L/0 % E#2"3/4"0

1. To determine negative and zero sequence reactances of an alternator.

2. To determine direct axis reactance (xd) and quadrature axis reactance (xq) of a salient pole

alternator.

3. To stud$ t#e 'T over current rela$ and determine t#e time current c#aracteristics.

4. To stud$ ferrant$ effect and voltage distribution in ,.. long transmission line using

transmission line model.

&. To determine location of fault in a cable using cable fault locator.

*. To stud$ operation of oil testing set.

+. To stud$ percentage differential rela$.

/. To obtain formation of bus and perform load flo% anal$sis

0. To perform s$mmetrical fault anal$sis in a po%er s$stem

1. To perform uns$mmetrical fault anal$sis in a po%er s$stem


5/23

E#2"3/4"0 N%$ 1A/4: To determine negative and zero sequence reactances of an alternator.

A22&3&0, U"!:

S$N% I0"4


6/23

F%3 S*/2 T"0:

PROCEDURE :

(&) O2" C/3=,/0 T"01. 7onnect t#e circuit as per circuit iagram.

2. @nsure t#at t#e external resistance in t#e field circuit of 7 motor acting as a prime mover foralternator is minimum and t#e external resistance in t#e field circuit of alternator is maximum.3. :%itc# on 7 suppl$ to 7 motor and t#e field of alternator.

4. :tart t#e 7 motor %it# t#e #elp of stator. T#e starter arm s#ould be moved slo%l$" till t#espeed of t#e motor builds up and finall$ all t#e resistance steps are cut out and t#e starter arm is#eld in on position b$ t#e magnet of no volt release.

&. d>ust t#e speed of t#e 7 motor to rated speed of t#e alternator b$ var$ing t#e external

resistance in t#e field circuit of t#e motor.*. ecord t#e field current of t#e alternator and its open circuit voltage per p#ase.

+. 'ncrease t#e field current of alternator in steps b$ decreasing t#e resistance and record t#e fieldcurrent and open circuit voltage of alternator for various values of field current.

/. =ield current of alternator is increase till t#e open circuit voltage of t#e alternator is 2& to 3percent #ig#er t#an t#e rated voltage of t#e alternator.

0. ecrease t#e field current of alternator to minimum b$ inserting t#e r#eostat full$ in t#e fieldcircuit.(+) S;%30 C/3=,/0 T"0

1. 9it# t#e 7 motor running at rated speed and %it# minimum field current of alternator closet#e s%itc#" t#us s#ortcircuiting t#e stator %inding of alternator.


7/23

11. ecord t#e field current of alternator and t#e s#ort circuit current.

12. 'ncreases t#e field current of alternator in steps till t#e rated full load s#ort circuit current.ecord t#e reading of armature in bot# t#e circuit at ever$ step. 4 to & observations are sufficientas s#ort circuit c#aracteristics is a straig#t line.

13. ecrease t#e field current of alternator to minimum and also decrease t#e speed of 7 motor

b$ field r#eostat of t#e motor.14. :%itc# off t#e 7 suppl$ motor as %ell as to alternator field.

(=) S*/2 T"0

1. 7onnect t#e circuit of alternator as s#o%n in =ig AB Ceeping t#e connections of t#e 7 motorsame.2. @nsure t#at t#e resistance in t#e field circuit of 7 motor is maximum.3. :%itc# on t#e 7 suppl$ to t#e motor.4. epeat steps 4 described is (a).

&. d>ust t#e speed of t#e 7 motor slig#tl$ less t#an t#e s$nc#ronous speed of t#e alternator b$var$ing t#e resistance in t#e field circuit of t#e motor. :lip s#ould be extremel$ lo%" preferabl$less t#at 4 percent.

*. @nsure t#at t#e setting of 3 p#ase ariac is at zero position.+. :%itc# on 3 p#ase 7 suppl$ to t#e stator %inding of alternator.

/. @nsure t#at t#e direction of rotation of alternator" %#en run b$ t#e 7 motor and %#en run asa 3 p#ase induction motor at reduced voltage (alternator provided %it# damper %inding can berun as 3 p#ase induction motor) is t#e same.

0. d>ust t#e voltage applied to t#e stator %inding till t#e current in t#e stator %inding isapproximatel$ full load rated value.

1. 8nder t#ese conditions t#e current in t#e stator %inding t#e applied voltage to t#e stator%inding and t#e induced voltage in t#e open field circuit %ill fluctuate from minimum values tomaximum values %#ic# ma$ be recorded b$ t#e meters included in t#e circuit. =or better results"oscillogram ma$ be taCe of stator current applied voltage and induced voltage in t#e field circuit.

11. educe t#e applied voltage to t#e stator %inding of alternator and s%itc# off 3 p#ase 7suppl$.12. ecrease t#e speed of 7 motor and s%itc# off 7 suppl$.

-bservation Table;

R",*0: 9e #ave performed t#e experiment and determine negative and zero sequencereactances of an alternator


8/23

E#2"3/4"0 N%$

A/4: To determine direct axis reactance (xd) and quadrature axis reactance (xq) of a salient polealternator.A22&3&0, U"!:

T;"%3: T#e directaxis subtransient reactance and quadratureaxis subtransient reactance of 3p#ase s$nc#ronous mac#ine can be measured b$ appl$ing a reduced single p#ase voltage to t#et%o stator p#ase connected in series" %it# t#e field %inding s#ort circuited and t#e mac#ine beingstationar$. T#e rotor is moved b$ #and" so t#at t#e current in t#e s#ort circuited field %inding ismaximum. 8nder t#is condition. T#e reactance offered b$ t#e armature is directaxis subtransientreactance i.e.

Dext t#e rotor is turned t#roug# #alf a pole pitc#" so t#at q axis coincides %it# t#e crest of t#earmature mmf and t#e current in t#e field %inding is minimum. T#e reactance offered b$ t#earmature under t#is condition %ill be quadratureaxis subtransient reactance. T#is met#odnecessitates an exact alignment of t#e rotor %it# t#e armature mmf %ave" %#ic# is not possible.s suc# a more convenient met#od discussed belo% can be adopted for t#e measurement ofsubtrasient reactances.

D/3"=0-/ ,+03&/"0 3"&=0&="> ?!irectaxis subtransient reactance can be determined b$ applied voltage met#od (most

convenient met#od) in %#ic# single p#ase voltage of reduced magnitude and of rated frequenc$

is applied across t#e t%o terminals of t#e stator %inding t#e t#ird being left isolated as s#o%n in

=ig AB. T#e test is repeated for anot#er t%o combinations of connections of stator terminals i.e.

first voltage applied bet%een terminals "E" second bet%een E"7 and t#ird bet%een terminals

7". uring t#is test rotor is stationar$ and t#e field %inding on t#e rotor is s#ort circuited

t#roug# an armature. T#e test s#ould be conducted at full load current flo%ing in t#e stator

%inding as suc# applied voltage s#ould be ad>usted accordingl$. irectaxis subtransient

reactance can no% be found out as discussed belo%.


9/23

C/3=,/0 D/&'3&4:

1. Let t#e applied voltage across t#e terminals "E of t#e stator %inding %it# terminal 7

Cept isolated be @ volts and t#e current flo%ing t#roug# t#e %inding in currentbe '

amperes. T#e ration of voltage across eac# p#ase to current is a reactance %#ic# can be

represented b$ a quantit$ B i.e.

2. :imilarl$ t#e ratio of applied voltage @B62 across eac# p#ase %it# voltage @B across t#eterminals E"7 and t#e resultant current flo%ing" 'B can be represented b$ a quantit$ EB i.e.

3. 'n a similar %a$ t#e ratio of applied voltage" @F62across eac# p#ase %it# voltage @Facross t#e terminals 7. and current flo%ing 'F is represented b$ a quantit$ 7B i.e.

4. =rom t#e value od B" EB" and 7B determined from t#e experimental data" calculate t#evalues of G and from t#e equations given belo%.


10/23

&. T#en directaxis subtransient reactance ?dF H G I (smaller possible stationar$ rotorreactance).

P3%="!,3":

1. 7onnect t#e circuit as per t#e circuit diagram.2. @nsure t#at t#e moving Cnob of single p#ase variac is at zero position.

3. :%itc# on t#e 7 suppl$.

4. ppl$ a reduced voltage to t#e circuit consisting of stator terminals and E in series" so t#att#e current flo%ing in t#e stator %inding is of full load value. ecord t#e voltage applied andt#e current flo%ing in t#e circuit.

&. epeat step 4 %it# stator terminals E and 7 connected in series.*. epeat step 4 %it# stator terminals 7 and connected in series.

+. epeat step 4" & and * for a ne% position of t#e rotor to confirm t#at t#e value of G and are same for t#e bot# t#e position of rotor./. :%itc# off t#e suppl$.

O+"3&0/% T&+*":

R",*0: 9e #ave performed t#e test and directaxis subtransient reactance of s$nc#ronousmac#ine.


11/23

E#2"3/4"0 N%$ .

A/4: To stud$ t#e 'T over current rela$ and determine t#e time current c#aracteristics.

A22&3&0, U"!:

1. oltmeter (3 ) igital

2. mmeter (1 ) igital

3. Loading 7.T.

4. uto Transformer 2+

&. 'ndicating Lig#t

*. '...T. ela$ T$pe 7!

+. Timer %it# :tart J :top facilit$

/. 5us# Eutton for Timer :TT J :T-5

0. otar$ :%itc#

1. 5 :%itc#

11. 'nsulating terminalsT;"%3: T#ere are several over current protection suc# as fuse" t#ermal rela$ J 'T ela$.'T ('nverse efinite inimum Time) ela$ is a #ig# accurac$ over current rela$. 'f %e doesnot %ant to flo% t#e current in lines more t#an 1 mp" %e %ill set t#e tripping current in ourrela$ 1 mp. s t#e current %ill become 1.1 or 1.2" t#e rela$ disc %ill start for%ard and tript#e breaCer after certain time. 't is %idel$ used to prevent over current on transmission lines"po%er transformers etc" because t#e error J tripping time of t#e rela$ is tolerable b$ t#e linesand transformer.

s t#e requirement of s$stem is t#at t#e faulted line s#ould be open instantaneousl$. 'f t#efaulted line breaCer fails to open t#e faulted line" t#e next suppl$ breaCer #ave to be open to formaCing dead t#e fault$ line. T#e next breaCer ma$ be at #ig#er voltage line or t#e same voltage.T#e next breaCer s#ould open onl$ after t#e first breaCer failure. :o %e %ill allo% approx .4 sectime to operate first breaCer. 'f first breaCer does not become open %it#in .4 sec t#an it %ill beassume failure and t#e next breaCer %ill become functional. T#ese time and current distinguis# ismade b$ 'T rela$.C/3=,/0 D/&'3&4:

P3%="!,3":

S0,! 0;" %2"3&0/' =,33"0 !"-%2"3&0/' =,33"0 % !/=$

(i) Geep t#e current source at minimum.(ii) T#e amp ad> 6 rela$ test rotar$ s%itc# is Cept at 5 K.

(iii) :%itc# -D t#e test set.


12/23

(iv) 'ncrease t#e current source slo%l$ and pa$ attention at disc of rela$.

(v) t certain current" it >ust moves in for%ard direction" t#is current is %2"3&0/' =,33"0andnote t#e current.(vi) Do% decrease t#e current t#roug# current source and pa$ #ard attention at disc.

(vii) T#e disc %ill stop at certain current and moves in reverse direction >ust after reducing t#ecurrent. T#is current is !"-%2"3&0/' =,33"0and note its value.

O+"3&0/% T&+*":

R",*0: 9e #ave dra% t#e c#aracteristics of 'T rela$ after performing t#e test.

E#2"3/4"0 N%$


13/23

A/4: To stud$ ferrant$ effect and voltage distribution in ,.. long transmission line usingtransmission line model.

A22&3&0, U"!: Transmission line model is consisting of four actions of transmission on lineoperatable at 22 %it# current rating at 2 connected in pi net%orC. continues variable po%ersuppl$ %it# t%o igital voltmeter and t%o digital ammeter mounted on front panel %it#esistive" 'nductive" 7apacitive load fitted in m.s. s#eet complete %it# patc# c#ords for

interconnection. dditionall$ one L5= 9attmeter is required if .E.7.. parameter %it# p#aseangle is to be calculated" for %#ic# t#e calculation are given in our manual.

T;"%3: Transmission line model consists of four sections and eac# section represents & Cmlong 4 G transmission line. 5arameters of & Cm long 4 G Transmission line are taCen as;

:eries 'nductance H / m,:eries esistance H 2 o#m

('n addition to resistance of inductancecoil) :#unt 7apacitance H .4+ micro=LeaCage resistance or :#unt 7onductance H 4+ Co#m

=or actual 4 G transmission lines range of parameter is

;l H :eries 'nductance H 1. to 2. m,6Gmr H :eries esistance H .& to 1.& o#m 6Gmc H :#unt 7apacitance H ./ to .1 micro=6Gm

g H LeaCage resistance (:#unt 7onductance) H 3 x 1I/ to & x 1I/ m#o6Gm

long transmission line dra%s a substantial quantit$ of c#arging current. 'f suc# a line is opencircuited for a ver$ lig#tl$ loaded at t#e receiving end" t#e voltage at t#e receiving end ma$become #ig#er t#en t#e voltage at t#e sending end. T#is is Cno%n as A=@DT' @==@7TB andis due to t#e voltage drop across t#e line inductance (due to t#e c#arging current) being in p#aset#e sending end voltage. T#e bot# capacitance and inductance are necessar$ to produce t#isp#enomenon. T#e capacitance and c#arging current is negligible in s#ort line but significant inmedium lengt# lines and appreciable in long lines. T#erefore" p#enomenon occures in mediumand long lines.

'n t#e p#aser diagram" =erranti effect is illustrated. T#e line ma$ be represented b$ a nominal picircuit so t#at #alf of t#e total line capacitance is assumed to be concentrated at t#e receivingend. - represents t#e receiving end voltage. -7 represents t#e current dra%n b$ t#ecapacitance assumed to be consetrated at t#e receiving end. D is t#e resistance drop and D5 isinductive reactance drop. -5 is t#e sending end voltage under no load condition and is less t#anreceiving end voltage.

C/3=,/0 D/&'3&4: F/',3" 1


14/23

F/',3"

P3%="!,3":

(i) ppl$ t#e voltage (2 max.) to t#e sending end and connect po%er factor meter. lsoconnect 1 ammeter and voltmeter to eac# end (receiving and sending).

(ii) 7onnect t#e load comprising of " L and 7 at t#e receiving end and note do%n t#e value ofreceiving end voltage.

(iii) Do% remove t#e load from t#e receiving end and note do%n t#e voltage on receiving end.T#is voltage at t#e receiving end is quite large as compared to sending end voltage.

O+"3&0/% T&+*":

R",*0: 9e #ave performed ferrant$ effect and voltage distribution in ,.. long transmissionline using transmission line model.

E#2"3/4"0 N%$ 5

A/4: To determine location of fault in a cable using cable fault locator.


15/23

A22&3&0, U"!:

1. #eostat 1.1 " / -#ms I 2 Dos.

2. !alvanometer I 1 Do.

3. easuring Tape (&) I 1 Do.

4. 3 7ore 7able (2&) I 1 Do.

&. 7 5o%er :ource I 1 Do.

*. igital ultimeter

T;"%3: ost of t#e distribution and part transmission of electrical po%er is no%ada$s carriedout t#roug# underground cables because of several advantages over t#e over #ead s$stem. an$a times locating a fault becomes a difficult tasC because cable is buried under t#e ground and isnot accessible. T#e faults %#ic# are most liCel$ to occur are ;

(a) !round =ault ; breaC do%n of t#e insulation of t#e cable %#ic# allo%s current to flo%

from core to eart# or to cable s#eat#.(b) :#ort 7ircuit ; cross or s#ort circuit bet%een t%o cables or bet%een t%o cores of amulticore cable.

mongst various met#ods used for localizing cable faults. urra$ Loop Test is ver$ commonand is described #ere.

T#is test is carried out for locating a ground or a s#ort circuit fault" provided t#at a cable runsalong %it# t#e grounded cable or %it# t%o cables (or %it# t%o cores of a multicore cable) %#ic#are s#ort circuited. T#e advantage of loop test is t#at t#e resistance of t#e fault does not affect t#eresults obtained. 5rovided t#is resistance is not ver$ #ig#. -t#er%ise it ma$ adversel$ affect t#esensitivit$.

C/3=,/0 D/&'3&4:

=igure 1

=igure 2


16/23

P3%="!,3":

1. TaCe a multicore cable (sa$ 3 core) of Cno%n lengt# (sa$ 2&). easure t#e resistance ofeac# core. aCe connections as s#o%n in =igure 1. :#ort circuit t#e t%o cores of t#ecable at t#e ot#er end. d>ust 5 and < suc# t#at balance is obtained. Dote 5" < andcalculate distance of fault x. TaCe t#reefour observations and taCe t#e mean of calculatedvalue of lengt# of t#e fault from eac# set of readings. T#is lengt# s#ould be equal to t#edistance of fault from t#e lo%er end of resistance ust 5 and < suc# t#at balance is obtained. Dote 5 and < in t#eobservation table. 7alculate x %it#. TaCe t#reefour observations and find average of x.calculate t#e distance of s#ort circuit fault from t#e measuring end of t#e cable.

C/3=,/0 D/&'3&4:

Localization of @art# =ault

18 E*"=03/=&* &! E*"=03%/=- E'/""3/' D"2&304"0D3%&=;&3)& G3%,2 %1 I-0/0,0/%-> G3$ N%/!&


17/23

Localization of :#ort 7ircuit =ault

R",*0; 9e #ave performed t#e location of fault in a cable using cable fault locator.


18/23

E#2"3/4"0 N%$ A/4: To stud$ operation of oil testing set.A22&3&0, U"!: -il Testing :et

T;"%3: 9#en a sample of oil is sub>ected to dielectric stress in a gap bet%een t%o sp#eres t#ematerials of #ig#er conductivit$ and #ig#er sp#eres capacit$ are dra%n into t#e intense fieldbet%een t#e sp#eres and causes a distortion of t#e field resulting in local #ig# densit$ anddisruption begins at t#ese points.

9#en testing transformer oil it is found often t#at one or more disc#arge occur across t#e gap atcomparativel$ lo% voltages due to t#e presence of %ater particles but t#at t#e voltage can beraised to a ver$ muc# #ig#er value before complete rupture occurs.

'f particles of #ig#er dielectric constant t#an t#e oil are dra%n into t#e intense field" t#e$ %illcause excessive local stress %#ic# ma$ result in dissociation or ionization of oil and t#e gases ofionization ma$ bridge t#e gap and causes complete rupture.

'n standard specifications for A'nsulating -ilB t#e met#od of appl$ing t#e testing voltage (%#ic#must be alternating or approximatel$ sine %aveform of frequenc$ bet%een 2& and 1 ,z and

%it# a peaC factor of 2 M& #as been laid do%n. T#e test #as to be carried out under standardconditions. T#e minimum dimensions of t#e test cell" diameter of t#e electrode and t#e distancebet%een t#em are specified.

P3%="!,3": 9#en testing oils t#e set is operated according to a particular met#od (in compliance%it# t#e regulations) i.e. %it# a fixed sparC gap and variable testing voltage. T#e voltage s#ouldbe increased graduall$ under continues observation of t#e measuring until t#e breaCdo%n occurs.To test oils of #ig# qualit$ t#e distance bet%een electrodes s#ould be ad>usted to 2 mm. T#eequipment permit 31 G6cm to be measured. =or testing oils of medium qualit$ or inferiorqualit$ t#e sparC gap s#ould be ad>usted to 4 mm b$ means of a distance gauge. T#e insulatingmaterial oil testing cup is equipped normall$ %it# t%o calottes#aped electrodes of 3* mm dia"radius of eac# sp#ere is 2& mm. T#e oil testing cup is Cept as small as possible to do %it#minimum quantit$ of oil. :uitable safet$ contacts are provided to put t#e set out of operation assoon as t#e top lid is opened in order to insert or remove t#e test cup" t#us eliminating ,Tdanger. T#e set is disconnected automaticall$ as soon as t#e puncture occurs. Do oil tests arepossible as long as t#e lid of t#e rear of t#e cabinet is open.C/3=,/0 D/&'3&4:

R",*0: istance bet%een electrodes H NNNN

EreaCdo%n voltage H NNNNN


19/23

E#2"3/4"0 N%$ 7

A/4: To stud$ percentage differential rela$.

A22&3&0, U"!:

1. ela$ :ingle 5ole ersion 1 (Dumerical T$pe) A@B maCe E7,122. Timer

3. uto Transformer 2+" 1 4. mmeter (1 " 7) 2 Dos.&. Deon lamp 1" 7" 23 *. #eostat & " 4& -#ms 1 Dos.

+. #eostat 1 " 2 -#ms 1 Dos./. 'solation Transformer

0. uxiliar$ 7 :uppl$ 8nit %it# Transformer

T;"%3: 't is a ver$ important protection of t#e transformer. 't is based on t#e ratio of ,.T.current and L.T. current s#ould be constant. 7onsider t#e =ig Do A1B" #ere %e considering t#esingle pole of 132633 G Transformer. 'tBs ,.T. current and L.T. current ratio %ill be 1;4. 'f t#e

7T of ,.T. side is considered 161 mp" so t#e 7T of L.T. side %ill be 461 mp. T#esecondar$ current of L.T. side 7T and ,.T. side 7T %ill al%a$s equal in normal condition. Eot#t#e secondar$ of 7Ts %ill enter in Dumerical t$pe ifferential ela$. T#e secondar$ of 7Tconnection is maCe in suc# a %a$ t#at t#e 7T current %ill flo% onl$ t#roug# coil circuit and noextra current is to flo% from ifferential coil. s soon as t#e fault occurs in transformer" t#e ,.T.current %ill #ig#. T#e ratio of ,.T. current and L.T. current %ill c#ange. T#e secondar$ of ,.T.side 7T current %ill become #ig# %it# respect to secondar$ of L.T. side 7T current. :o t#edifference of current %ill flo% t#roug# differential %inding. T#e secondar$ of differential%inding transformer %ill go to an electronic circuit t#at %ill operate a tripping rela$ to trip t#ebreaCer of main transformer. T#e t#roug# %indings are used to restraining t#e differential rela$.'t %ill more clearl$ b$ dra%ing t#e curve bet%een t#roug# current and differential current.

C/3=,/0 D/&'3&4:


20/23

O+"3&0/% T&+*":

R",*0: %e #ave perform t#e test on percentage differential rela$.

E#2"3/4"0 N%$ 9

A/4: To obtain formation of bus and perform load flo% anal$sis


21/23

=rom To ?

z H O 1 1. 2 ./

1 2 .4

1 3 .22 3 .23 4 ./PQ

H $bus(z) bus admittance matrix'bus H O>R1.1Q >R1.2&Q Q PQ vector of in>ected bus currentsSbus H inv() bus impedance matrixbus H SbusR'bus

E#2"3/4"0 N%$ 6A/4: To perform s$mmetrical fault anal$sis in a po%er s$stem%rite a matlab program for t#e fault anal$sis


22/23

z12 H >R./Q z13 H >R.4Q z23 H >R.4Q

bus H >RO/.+& 1.2& 2.&1.2& *.2& 2.&

2.& 2.& &.PQ

Sbus H inv(bus)

Sf H >R.1*QHO1Q 1Q 1PQ'3= H (1)6(Sbus(3"3)MSf)= H '3=RSbus(;"3)'12 H (=(1) =(2))6z12

'13 H (=(1) =(3))6z13'23 H (=(2) =(3))6z23


23/23

E#2"3/4"0 N%$ 18

A/4: To perform uns$mmetrical fault anal$sis in a po%er s$stemS133 H >R.03Q S33 H >R.1/Q S233 H >R.00+Q Sf H >RQdisp((a) Ealanced t#reep#ase fault at bus 2)'a2= H 1.6(S133MSf)

disp((b) :ingle linetoground fault at bus2) '3 H 1.6(S33 M 3RSf M S133 M S233)Q'12HO'3Q '3Q '3PsctmQ

'abc3 H sctmR'12aH'3RS33a1H1S133R'3a2H'3RS233aHaMa1Ma2

bHaM(.&./**R>)Ra1M(.&M./**R>)Ra2cHaM(.&M./**R>)Ra1M(.&./**R>)Ra2

25 E*"=03/=&* &! E*"=03%/=- E'/""3/' D"2&304"0D3%&=;&3)& G3%,2 %1 I-0/0,0/%-> G3$ N%/!&

Date post:	13-Feb-2018
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