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DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
Subject Name:Protection and Switchgear Subject Code: EE T82
Prepared !"
Mr. D. Raja, Assistant professor/EEE
Mr. B. Partiban, Assistant Professor/EEE
Mr. C. Adrien Peri!ana!a"am, Assistant Professor/EEE
#eri$ied %!" Appro&ed %!"
'(e)tion an* ++ Mar*)
,nit I
#. Describe te essentia$ %ua$ities of protecti&e re$a!in"
'() Ma!*#+,Apr*#, Apr*#-,
-. Deri&e te uni&ersa$ to%ue e%uation ') Ma!*#+
,Apr*#,No&*#-,Apr*#-,
. Discuss te basics idea of re$a! protection and a$so nature and
causes of fau$t') Ma!*#+
+. ist out te conse%uence of fau$ts'0) Ma!*#+
. Describe te princip$e of operation of an induction cup t!pe
re$a!') Ma!*#+
1. E2p$ain te four basic functiona$ caracteristic of a
protecti&e re$a! '1) Ma!*#+
3. E2p$ain brief$! about te c$assification of re$a! '1) Ma!*#+.
Apri$*#(. Describe te construction and 4or5in" princip$e of ant t4o
e$ectroma"netic induction
re$a! 4it neat dia"rams.'##) Apr*#, Apr*#-,
0. Describe te different termino$o"ies re$ated to re$a!'##)
No&*#-
#6. Describe te operatin" princip$e of a re$a!'1) No&*#-
##. E2p$ain c$ear$! about te t4o different operation princip$e
of e$ectroma"netic re$a! '##).
No&*##
#-. 7at is uni&ersa$ re$a! tor%ue e%uation8 9sin" tis
e%uation deri&e te caracteristic of an
impedance re$a!. Dra4 te operatin" caracteristic of R*
dia"ram.'##) No&*#-
,nit-II
#. 7it neat dia"ram, e2p$ain te construction and operation of
induction t!pe directiona$
o&er current re$a!'() Apr*#+, Apr*#,No&*#
-. ist out te dra4bac5s of static re$a!s') Apr*#+
. E2p$ain te construction and 4or5in" princip$e of time distance
re$a! 4it neat s5etc'1)
Apr*#+,Apr*#, No&*#
+. E2p$ain te princip$e of &o$ta"e ba$ance differentia$
re$a! ') Apr*#+
. Describe te construction, princip$e of operation and
app$ication of a directiona$ o&er
current re$a!'##) Apr*#+, Apr*#-
1. 7at is an ;DM< caracteristic8 E2p$ain o4 tis is
acie&ed in practice.'1) Apr*#+
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3. Define static re$a!. 7at are a$$ its components8 E2p$ain its
feature 4it basic operation.
'##) Apr*#
(. E2p$ain 4it a neat scematic dia"ram te caracteristic and
4or5in" of Static mo re$a!.
'##) Apr*#-
0. =o4 can different distance re$a! caracteristic be acie&ed
4it te e$p of amp$itude and
pase comparators8 Dra4 te t!pica$ distance caracteristics.'##)
No&*##
,nit-III
#. 7it a neat scematic e2p$ain te construction and 4or5in" of a
buco$> re$a! for
transformer protection8 Apr?#,
-. E2p$ain te different scemes emp$o!ed for bus bar protection
4it neat dia"rams. Apr?#,
Ma! #+
. A star connected, pase #6 M@A, 1.1 @ a$ternator as a per pase
reactance of #6. ;t
is protected b! mer>*price circu$atin" current princip$e 4ic
is set to operate for fau$t
currents not $ess tan #3 A. ca$cu$ate te &a$ue of eartin"
resistance to be pro&ided in
order to ensure tat on$! #6 of te a$ternator 4indin" remains
unprotected. Apr?#
+. ist te common transformer fau$ts. E2p$ain o4 eac of fau$ts
are protected 4it neat
scematic. Apr?#. Describe 4it a neat s5etc te mer> price
protection of differentia$ protection sceme.
Apr?#-
1. Describe te princip$e of operation of carrier current
protection of transmission
$ines.Apr?#-
3. 'a) e2p$ain te modified differentia$ protection for
a$ternators. Ma! #+
'b) 4it neat s5etc, e2p$ain te compreensi&e re$a! protection
for AC motor. Ma! #+
(. A pase transformer a&in" $ine &o$ta"e ratio of 6.+ @
/ ## @ is connected in star
de$ta and protecti&e transformers on +66 @ side a&e a
current ratio of 66/. 7at must
be te ratio of protecti&e transformers on ## @ side8. Ma!
#+
0. 'a) E2p$ain te protection of a tree pase a$ternator a"ainst
unba$anced $oadin". Ma! #+
'b) Discuss brief$! about te &arious scemes of protection
emp$o!ed for transmission $ine.
Ma! #+
#6. Describe te princip$e of mer>* price s!stem for te
protection of po4er transformer and
e2p$ain te prob$em encountered in differentia$ protection of
transformer. Ma! #+
##. Describe te protection of te stator 4indin" of a tree pase
a$ternator a"ainst inter turn
fau$ts. No&? ##
#-. E2p$ain te importance of testin" of re$a!s and describe te
procedure of commissionin"
tests on re$a!s. No&? ##
,NIT-I#
#. E2p$ain te current coppin" and capaciti&e current
brea5in" in detai$s. Ma!? #+
-. Describe te penomenon of current coppin" and capaciti&e
current brea5in" 4it
dia"rams and 4a&eforms. Apr? #, Ma!? #+
. E2p$ain 4it a neat dia"ram te capaciti&e current brea5in".
Apr #-
+. Deri&e te rate of rise of restri5in" &o$ta"e and
brief$! discuss its importance.
. E2p$ain te i" and $o4 resistance metod of arc %uencin" in
circuit brea5er 4en its
contacts separate. Apr? #-
1. E2p$ain te fo$$o4in" metods of e2tin"uisin" te arc in circuit
brea5ers'a) =i" resistance interruption
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'b) Current ero interruption
3. E2p$ain o4 arc is initiated and sustained in circuit brea5er
4en te circuit brea5er
contacts separate. No&? ##
(. E2p$ain 4it neat dia"ram arc penomenans and arc %uencin".
No&? #-
0. State te princip$e of arc e2tiction. Discuss te t4o teories
of arc interruption. Ma!? #+
#6. State te princip$e of arc e2tinction. 7at are te metods of
arc e2tiction8 Describe ten
in detai$. Apr?#
##.7at is te need of resistance s4itcin" 8 E2p$ain te process
4it neat s5etc. Apr?#
#-. A pase a$ternator as te $ine &o$ta"e of ## @.
