Giáo trình Bảo vệ rơ le – Dự án RE II

Giáo trình Bảo vệ rơ le – Dự án RE II

1.1. Những vấn đề cần đề cập trong việc thực hiện bảo vệ hệ
thống cung cấp điện.
1.1.1. Những vấn đề chung về bảo vệ rơle
 !"#$%&'%(%%)#%*+!+,-./)0+1#%23!,#%/)
#$%#456+*&(+%7.89(:&/)+;%<=$%#%>?+@A+"+-%B#C
-%B9D+"+#>?%E-0+"+56+*#%>?;F#%G%/)
#>EHI./)#J;%"+A&(./)"-/K:;%"#%,-
"+#%/7#=L+1HI#J+A+%4M !A+1#%2=L.*#1 !":N+
+%-%F-&(=L%>%O;%/./)"-=L/K:#%,-0+"+%8#/P!#%Q;%<
#%29(:&/)+=$%#%>?&(#R%S.L%+@A+"+:"M-%"#9(:&/)+5
5&(+@A#(%)#%*=L/K:
"++%7.89(:&/)+;%<=$%#%>?9(:+%./)"-0HI
./)&(#B5*9)+%;%O//D/%4+%-%F-&(7!.2;FH(/#$%#4
(M+1#%23!,#%/)56+*
%>&'M56+*9(:*/9456%4#.8=$%#%>?+@A%)
#%*1/+%!&(+"+%8#/P!#%Q1//P0+I+"++%7.89(:&/)+
;%<=$%#%>?+1#%2#4!M+T3!,#%/)56+*
U!*H!M#$%4#.8=$%#%>?+@A%)#%*&(+@A+"+%8
#/P!#%Q;%/3!,#%/)56+*0+B-%"#%/)+(%A%+(#*#+%V56+*
&(+"+%9M+%WA;%O/-%B;%<=L%>%O0H.1-%B+I94/&X
H!M#$%4#.8=$%#%>?0.Y#%?/9(:/K:.>E+56%>%4/+@A
-%B=L56+*
%/7#=L=K&)T9G9(94/#%/7#=L#6.8=K&)+1+%N+J
#%6+%/)#*#MP!+B!P!#P
"+%)#%*./)%/).4/;%<#%29(:&/)+=$%#%>?7!
#%/7!#%/7#=L=K&)T9GK&)T9G#%GHZ/9/P#Q+#$%#4&(+%7
.89(:&/)++@A#,#+K+"+-%B#C+@A%)#%*./)[%/3!,#%/)56+*0
=K&)T9G+\#-%B#C%>%O094/1A;%O/:4./)%?:"M+\#
./)

[%/3!,#%/)+%7.89(:&/)+;%<=$%#%>?0=K&)5]-%"#
%/)&(#^M#%GMP!+B!+1#%2#"+.8.2;%</-%Q++%7.89(:&/)+
=$%#%>?+@A-%B#C;%<=L56+*%_+="%/)!+%%`&/P
#6+=/7##$%#49(:&/)+;%<=$%#%>?# !"#$%&'
%(%,#;a56/".4(# !"#$%+!+,-J9>E./)
:(+%W#A;%<H6;/7#>D+.>E+.b!HX.7%c=,#9E/9DH*/
d
Giáo trình Bảo vệ rơ le – Dự án RE II
&D/569(:&/)++@A%8#/P!#%Q&(+e.b!HX.7%c#S#%,#
%/P:#f.*/&D/b;/%#7 !*+/Ag.1056.K:=K9/P#Q+
+!+,-J9>E./)&(5694/#h%A%%,#+1#%2.>E++"+-%B
#C=L56+*A;%O/%)#%1./).2#%/7#9'-#i94/+"+%4#.8=$
#%>?+@A%)#%*+1:8#&A/#I !A#f
1.1.2. Phân loại rơle
j%/Pk!9Al/T9G&Tj/!MP9/j&Ak+%>j+J9Ak:&/Pl+`j#;%Aj+
%A!g&`lM+j%/Pk!+Aj+%.Pm-%`9Al/T9Gn
Ao%`9Al/#%G!MP9/j9Ak:&/Pl+<k:+Aj+%j:
pT9G./Pl+TqT9G./Pl#>k0T9G#>k./Pl0T9G./Pl#>k-%`+>l+0
T9G+Am:>j0o
pT9G%/Pl#
pT9G#>k
pT9G./Pl#>mr=AjH`s0&/:Al+%
pT9G5<j
=o%`#%G!MP9/j#Aj+.<l+!mA+T+`j!+%`j-%Ak%
pT9G+j#/Pj-./Pm:n9Al/AkM#Aj+.<l9P:Al+%=Jk+Aj+%.j
:Tm+Aj+#/Pj-./Pm:
pT9G;%<#/Pj-./Pm:qT9G#/s%on9Al/AkM#Aj+.<l=Jk+Aj+%
#%AM.<m/.<l#<l#+Aj+#%A:5<j+!mA+T+`j!+%`j-%Ak%:Jj+#:Al+%./Pk!
;%/Pm%>n./Pl+Am:0./PlH!0./Pl#Tm0
+o%`9Al/#%G.Jl+#/j%#%A:5<j&Ak

pT9GHk./Pl
pT9G./PlAj-
pT9G+<5!`j#
pT9G#<m#Tm0
Ho%`9Al/#%G+Aj+%:Jj++T+`j!
pT9G5T+`j-n9Al/AkM.>Tl+:Jj+#>l+#/Pj-&Ak:Al+%./Pl+`k=Am
&Pl
pT9G#%>j+`j-n9Al/AkM:Jj+&Ak:Al+%#%< !A=/PjAj-.
9>Tk%AM=/PjHk./Pl
Go%`#%G/Aj#/l&Ak+%/Pk!+Aj+.Al/9>Tl./&AkT9G
pT9G+>l+.Al/
pT9G+>l+#/Pm!
t
Giáo trình Bảo vệ rơ le – Dự án RE II
pT9G+>l+.Al/r+>l+#/Pm!
pT9G59Pl+%
pT9G./l%%>Tj

1.1.3. Đặc tính vào -ra của rơle

u!A%Pl/>sA.Al/9>Tl&Ak&AkA+!mAT9G%>%/k%:/%%fA
[%/3=/Pj#%/P#>kv.Pj3t#%/kMwMd.Pj;%/3w3t#%/kM#J#>k
MwMd.PjMwMtq%AmM=`l+oPj!3#J#/Pj-#%/kM;%<.<m/MwMt[%/
3/Am:#>k3t&Pk9Al/3d#%/kMwMt.Pj3w3d#%/kM/Am:#>kMt&PkMwMd
1.1.4. Các loại rơle thường gặp trong hệ thống bảo vệ Rơle
1.1.4.1. Rơle điện cơ
a) Rơle điện từ
Nguyên lý làm việc
x>l9Ak:&/Pl++!mA9Al/T9GAkMH>lA#P!MP9/j./Pl#>kyGj#:<l#
T9G%>%/k%:/%%fA[%/+%Hk./Pl/./&Ak+!<lH`M+!mAA:

+%`:./Pl#%/kJj-5Gs+%/l!:<l#9>l+%!j#z>l+%!j#./Pl#>k.Jl#&AkJj-
[%/Hk./Pl&Ak+!<lH`M/{
#.
qHk./Pl#Aj+.<lo#%/k9>l+z%!j#
Jj-&Ak;%/9>l+z#J#%/k;%G%Tm/Am:/Am:o9Ak:.j#/Pj-./Pm:qH#/Pj-
./Pm:.>Tl+Jj&Tj/Jj-o
[%/HI./)/K:.7/"#L
#&
qHk#Tm&Pko#%/k9>l+%W#./)#h
/K:[%/96+9k3z
9k3
{zq9>l+./Pl#>ko#%$T9G%Am
|
Giáo trình Bảo vệ rơ le – Dự án RE II
Sơ đồ minh hoạ nguyên lý hoạt động của rơle điện từ
Một số loại rơle điện từ
pT9GHI./)&(./)"-
pT9G#!/An%/Pl:&!l+%/j%+!mAT9G#!/A9Ak;%!Pj+%
.Al/#/j%/Pl!./Pk!;%/Pm0j#%>TkJk:Tm&/l#/j#!/A/>sA+Aj+T9G
;%Aj+Jl+./Pm:T9G#!/A+j+T+`j!./Pk!+%/m%./PlAj-#Aj+.<l.Pm
+j#%Pm#Aj+.<l;%/./PlAj-#J/Am:#;%Am}d~•
.:

pT9G#%?//Ang!k.PmH!M#/k#%Tk//A.j+%`l:%Jl+:Tm
+%`l:+!mA%Pl#%<j#/Pj-./Pm:5&Tj/#%Tk/./Pm:.>A#/j%/Pl!#Aj+.<l&Ak
T9G%Tk//A+%`l:AkM+j#%Pm&Ak/-%`k/`M+%.Pj%Ak/Tk
pT9G-%`+>l+9Ak:<l#HAl+!mAT9G./Pl#>k+j#%P:#>k#%<
-%`+>l+HA:+%`:&/s%+>m!#AlP%!MPm.<l+!mAJj--%!l
#%!<l+&Ak+%/Pk!Hk#+!<lH`M[%/+%>A+jHk./Pl#%/k-%`k
.<lT9G.AsTm:<l##%A/&/l#/jH9>l+%!j##>k#>TkA:+%`:&/s%

+>m!
T9G-%`+>l+:Al+%#>kA:+%`:&/s%+>m!+j+`j!#!j+5A+%
:<l#-%/jA;%G%Tm;%<;%/j9Tj+k:<l#-%/jA%m.Pm;%/+%Hk&Ak
+!<lH`MA:+%`:#%/k#<m9>l+%!j#./Pl#>k+!mA+!<lH`M&AkA:+%`:
&/s%+>m!-%`+>l+%A/=P;%<=Jk%A!0Jj-=/l%!j#&Pk:<l#=P09>l+
%!j#A:+%`:&/s%+>m!9Ak:%/Pl:&!l/>sJj-;%/+Jj#./Pl+!<lH`M
€
Giáo trình Bảo vệ rơ le – Dự án RE II
U!<jJj-+%!MPm.<l>Tl+9Al/#%/k-%Am/.<m/+%/Pk!Hk./Pl.Pm.<m/
+%/Pk!9>l+%!j#./Pl#>k
Al/AkM+j>!./Pm:+%/j%9Ak.<l%AlM+A0;/j+%#%>Tj+l0#%Tk/
/A#Aj+.<l%A%
b) Rơle điện động
Nguyên lý hoạt động
%G!MP#Jj+0T9G./Pl.<l+j%A/+!<lH`M%>%/k%:/%
%fA
[%/+jHk !A+!<lH`Md9Ak/
d
&Ak+!<lH`Mt+jHk./Pl/
t

Al/&/l#/j%>%/k%:/%%fA#A+j+Am:>j#>k
dt
w[•/
d
&Ak+j9>l+./Pl
#>kzw[‚
dt
/
t

%AM9>l+zw[
d
‚/
d
/
t
5Gs5/%A:<:GUw[/
d
/
t
.Jl#
9P+!<lH`Mt09Ak:+!<lH`Mt !AM&Ak.j#/Pj-./Pm:Pj!%A/+!<l
.>Tl+:Jj+<j/#/Pj-#%/k/
d
w/
t
w/+jUw[/
t
9!j+AkM:<:G.<l+9`l-&Tj/
+%/Pk!Hk./Pl[%/:Al+%./Pl3AM+%/Pk!&Tj/#`k5<jƒ#%/k#%/kz#%AM.<m/0
T9G5Gs9Ak:&/Pl+&Tj//Aj#/l#!=/k%+!mA9>l+./Pl#>k&Ak:<:G
[%/:<l##%A/+!<lH`M.>Tl+.<m/+%/Pk!Hk./Pl#%/k+%/Pk!:<
:G#!=/k%U
#=
+!s#%AM.<m/
Ứng dụng
T9G./Pl.<l.>Tl+5>mH!l9Ak:T9G+<5!`j##Aj+H!l0-%Am
;%Ajj#%Pm+%Pj#AlT9G5Jj#./Pl.<l.Pm#J#/l5<j:<:GU#=&Ak5Gs
#J.<l%AlM+!mAT9GAl/T9G./Pl.<l3AM+%/Pk!;%<+j:Al+%
5Jj##>k#!MU#=%m%>H!k%/Pk!##>l.<l./Pk!;%/Pm

c) Rơle từ điện
Nguyên lý làm việc
~
Giáo trình Bảo vệ rơ le – Dự án RE II
x>l9Ak:&/Pl++!mAT9G9Al/AkMH>lA#P+T5Tm9>l+./Pl#>kH#>k
#>Tk+!mAA:+%`:&/s%+>m!#Aj+H!l9P:<l#+!<lH`M;%/+jHk
./Pl+%AlM !A!MP9/j+%!=/Pm!H/Ps%>%/k%:/%%fA
>k#>TkA:+%`:&/s%+>m!&Tj/+Am:>j#>k#Aj+H!l9P
;%!+jHk#AlA:<:G !AM
>l+./Pl#>k9Akzw[•
dt

U<:G !AMUw[q#/m9Pl&Tj/Hk./Plo
Đặc điểm
T9G#>k./Pl+j.<l%AlM9Tj0+<5!`j##Aj+.<l%mq+Tsdvrdv„o
5>mH!l%/Pk!##>l.<l%jA0+<5!`j#./Pk!;%/Pm+Tsd.Pjt…
[%<9Ak:&/Pl+Tm:Al+%3AM+%/Pk!&/kTm:Al+%3AM+%/Pk!:<:G
#!=/k%U
#=
wv
d) Rơle nhiệt

T9G%/Pl#9Ak:<l#9Al/#%/Pj#=/l./PlH!k.Pm=Am&Pl.<l+T&Ak
:Al+%./Pl;%m/=/l !Aj#Am/0#%>TkH!k;Gk:&Tj/;%Tm/.<l#>k0+<#Jj+
#Tg!kTm./PlAj-3AM+%/Pk!.Pj~vv0#`k5<j~v†09Al/:Tj/
.:
.Pj
d~v./PlAj-:<l#+%/Pk!#Tj/€€vT9G%/Pl#;%<#Aj+.<l#>j+#%Tk/
#%G#/lHk./Pl&/k+j !Aj#/j%%/Pl#9Tj-%Am/+`k#%Tk//A.Pm-%Aj#
j%Tk//A9Ak:&/Pl+#>k;%Am&Ak//`M‡5ˆ.Pj&Ak/-%!j#0P;%<

H!k.Pm=Am&PlJj:Al+%.>Tl+U!<j=Am&PlJj:Al+%#%>TkH!k
;Gk:+`k!+%AmM
!MP9/jH>lA#P#Aj+H!l%/Pl#+!mAHk./Pl0AkMAM5>m
H!l-%<m=/PjT9G%/Pl#+j-%/Pj;/:9Al/;Gj-0!MP9/j9Ak:&/Pl+H>lA
#P5>l;%Aj+%A!&Pk/AsTmHAk/+!mA%A/;/:9Al/;%/=/l.<j#j%`k
#>m+T=AmT9G%/Pl#9Ak-%/Pj;/:9Al/;Gj-q=/:G#A9o+`j!#Al#>k%A/#`j:
;/:9Al/0:<l##`j:%Pl5<j/AsTm=Gjq#%>TkH!k/&A+j|‰•/0‰€•
‰
Giáo trình Bảo vệ rơ le – Dự án RE II
zGo:<l##`j:%Pl5<j/AsTm9Tjq#%>Tk9Ak.<k#%A!%AM#%Gj-+<:r
/;G0%>.<k#%A!/AsTm`j-tv9`k/&AoA/-%/Pj%Gj-9Al/&Tj/
%A!#%Ak%:<l##`j:=Jk-%>T-%Aj-+Ajj%Jl+%Ak
[%/.<j#jHHk-%/Pj;/:9Al/;Gj-!<j&Pk-%/jA;/:9Al/+j
%Pl5<j/AsTm%m%T0+j#%PmH!k#>l+#/Pj-+%Hk./Pl !A%Jl+H`M
./Pl#Tm=A !A%Pm.<l!<j+9TjMP!+`k!-%/Pj;/:9Al/-%Am/+j
+%/Pk!HAk/9Tj&Ak:mPj!+`k9>l+.`mM:Al%#%/k+%Pj#Al#`j:-%/Pj
<l0HAkM&AkJj
e) Rơle điều khiển
j+%>j+J%>:<l#T9G#!/A0%>+j;/j+%#%>Tj+%m0
#`k5<j#%A#Aj+9Tj0;%AmJJj#9Tj0%Pl5<j%Am+A
1.1.4.2. Rơle tĩnh
a) Những hạn chế của rơle điện- cơ
%.Pj;%Am%>sJ:Šv+Aj+#%/Pj#=/l=Am&PlT9G+%!mMPj!
+!s+%/m#%>l+%/Pl&Tj/+T+`j!55Aj%9Ak./Pl#>k&Ak+T;%/j0+T+`j!#%>kA
%Ak%9Ak#/Pj-./Pm:%Tl-;/:
T+`j!.&Ak55Aj%+Tr./Pl#>k+j%>s.Jl+./Pm:n
r%`l:n:Al+%./Pl#>k.:`j#;%Amtv:50+T+`j!55Aj%.k
=`mM09k30+!<lH`M%A%+!s+Tsdv:5
r[Gj:+%/j%3Aj+n&/Pl+../Pl#>k#>Tj+;/Advv0.Aj-+!mA+Ts
dvv%>Tk#%>Tk. !A=/PjHkqo~;%< !A9l+0;%/.

9`s+Am#%Ak%-%`k#`k5<j+<%/Pl-&Tj/+Aj+#%Ak%-%`k#>lH&Ak%Ak/
%>s#%Ak%-%`kAkM#%>Tk;%Aj9Tj+j#%Pm9Ak:5A/;Pj# !Am.`j#
%/Pk!
rT+`j!.&Ak55Aj%9Al/#%>Tk+%/m9Ak9Al/..T=/Pj0:<l#
Hk%Jl+:<l#Aj-%>Tk;%j#%>l+%/Pl.>Tl+%>s-%Gj-3>m9/j-%>j+
#Al-+`k+j%>+Aj+-%Gj-5<j%l+0/Am/#/j+%0-%Gj-#Ps0-%Gj-.Pj:0
g.j:!<j=Am&Pl+%:<l#.<j/#>Tl.T/Am9Ak:<l#.>TkH`M
-%`-%<j/0+!s-%Am/+`kH!k#Tj/:>Tk/-%`k#>mT9G0;Gk:#%G:<l#5T
.<k<j/H`M-%>j+#Al-+%/Pj::<l##!m#%/Pj#=/l%/-%/j+A:Ak.<l#/+`lM0
+%/j%3Aj+0#<j+.<l&Ak+Aj++%>j+J=Am&Pl#%/k;%/P:#*
b) Rơle tương tự
T9G9Al/AkM+j.Jl+#>9Ak+Aj+#%<5<j&Ak‹AT9G%>Hk0
Aj-0j+9Pl+%-%A0+<5!`j#09Ak+Aj+.Al/9>Tl9/P#!l+qAA9o/j%/Pl!
AkM.>Tl+55Aj%&Tj/:<l#%AM%/Pk!.Al/9>Tl.`k!&Ak+j/Aj#/l+%!`m
.Pm+%#/j%/Pl!.`k!AqT9G9Al/AkM<k:+Aj+9Al/T9G=AjH`s0T9G./Pl
#>mo`j!#!j+T9G9Al/AkM<k:+Aj+;%<j/5A!n
Š
Giáo trình Bảo vệ rơ le – Dự án RE II
* Khối tiếp thu
[%<j/AkM<k:%A/-%`k+%/j%9Ak=<l.9>Tk&Ak=<l55Aj%0.Al/
9>Tl.`k!A+!mA=<l-%`lAkM<k::<l##%A//Aj#/l+%!`m
p<l-%`l.9>Tkn9`jM#/j%/Pl!#>k+Aj+:AjM=/PjHk.Pm=/Pj
.<m/#%Ak%.Al/9>Tl:<l#+%/Pk!%Tk+`k!+%/m%9>!
p<l55Aj%+j#%Pm9Ak:&/Pl+#%G%A/!MP#Jj++%/j%9Akn
rx5Aj%%A/.Al/9>Tl./Pl#%G/Aj#/l#!MPl#.<j/qH!k+%+Aj+
T9G=Am&Pl;%Am+Aj+%0=Am&Pl59Pl+%0=Am&Pl !AjAj-0=Am&Pl;Gj:
Aj-0o
rx5Aj%%A/.Al/9>Tl./Pl#%G/Aj#/lj+-%AqH!k+%T9G
=Am&Pl;%Am+Aj+%0T9G./l%%>Tj+<5!`j#0o
* Khối thực hiện

U!l+./j+%+!mA;%<j/AkM#%>l+%/Pl%>s=/Pj.<m/.<l#<l#+!mA
:Al+%./PlAk/%>;%!Pj+%.Al/#/j%/Pl!.Pm.>A.Pj+!<l+Jj#:AjM+Jj#
* Khối trì hoãn
U<l#:Al+%;%Aj+.>Tl+5>mH!l##T9G#/s%9Ak:Al+%#/+%
-%`05>mH!l;%`!+%/j%9Ak:<l#;%`!;%!Pj+%.Al/#%!`l##Ajq[o
UAl+%#/j+%-%`H!k.Pm#/k%As;%<j/+%/m%./l%
Tj/T9G#/s%+%-%Gj-&/Pl++%/m%./l%+Aj+=<l-%`l#T9G.Pm
-%<j/%Tl-=Am&Pl0#%<#%>Tk+j%A/+Aj+%n
p%/m%./l%+Aj+#%<5<j.`k!&Ak.Pm-%!k%Tl-&Tj/T9G
p%/m%./l%+Aj+#%<5<j+%!`m#;%<j/55Aj%.Pm3Aj+./l%
>Ts#Aj+.<l+!mAT9G
c) Rơle kỹ thuật số
Jl+./Pm:n+Aj+#/j%/Pl!3>m9/j=P#+!mAT9G;/s#%!`l#5<jTmHAl
5<jqHAl%/l-%`v0do:Akj+j#%Pm#%>l+%/Pl%/Pk!+%>j+J#!`k#>l
/j%/Pl!.`k!&Ak.>Tl++%!MPm5A#/j%/Pl!5<j.Pm./Pk!;%/Pm#/j%/Pl!A
*) Chức năng và cấu trúc tổng quan rơle số
U<l#T9G5<j+j%>s9Al/%/Pl:&!l+%>j+J5A!n
do%>j+J.9>Tkn9Ak+%>j+J.`k!#/P&Ak !A#l%`j#0
%Jk:.09l+0#/j%A%>s#%<5<j:Al+%./Pl:AkT9G-%Am/+A%Aj+
9>Tl&Ak.`k!#/Pj/+%!9Akn
rgk=A-%A0Hk#!#/j%
rj-=A-%A0Aj-#%>j#>l†P<
Œ
Giáo trình Bảo vệ rơ le – Dự án RE II
x<j9>Tl&Ak+!l#%Pm9Al/#!kMMP!+`k!+!mAT9G%>s9>TlAkM;%/
;%<+j5>l+<j#%>Tk9Ak%/k%5/&Ak+`=Jk0Hk#!#/j%0Aj-#%>j
#>l†P<=Jk;%<%>;%/5>l+<j5Gs+j:<l#=/Pj.<l:Al%+!mA
#%Ak%-%`k#`k5<j+<%/Pl-0#%>Tk;Gk:#%G:`j#.<j/3>j;%/Pj
5/%A+Aj+#%Ak%-%`k#%>j#>l%/l+%&Ak†P<U<l#Gj#.Jl+=/Pl# !A#l
;%Aj+>sA9Ak;Gk:#%G.j#%>Tk5/%A%>s#%Ak%-%`k !Aj.<l#>lH

9Tj0;%<+%!;/k0;%/PjHkAj- !Aj.<l+<j:`j#HAl%/k%5/
g.j%>sHkAj-.&Ak+`k.>Tl+n
r/Pj%m9Al/=Jk%>s&Ak.Jl+=/Pl#q;%<=As%kA0
HAm/.<lo
rl+#%<#%`j-A#%Ak%-%`k#`k5<j+<%/Pl-<k:9l++>j0
;%/+`k;Pj#%Tl-9l+=Jk-%`k:Pk:
r%!`m%jA.Pj:>j+./PlAj-#%/j+%%Tl-0 !/./l%+Tst>j&Tj/

./l%:>j+
&Ak>j&Tj/dv
./l%:>j+

%>s&/Pl+#P#%>l+%/Pl+%!mMPj!=Jk-%`k+>j
to%>j+J9`j-:`s!0#/j%#Aj+A%5>l+<j0;%Tm/.<l+Aj+T9G
+%!mMPj!<k:+Aj+&/Pl+5A!n
p`j-:`s!Hk0Aj-0#`k5<j0.Pj:-%A.>A&Ak=<l.Pl::`s!
pl+5<j#/Pj-Pj!+`k
p/j%#Aj-%`#/j+%A+Aj+5<j9/Pl!+`k%>n
rgk0Aj-%/Pl!H!lq%Jl+5<j/A∆!0∆/o
rAj+#%Ak%-%`k#%>j#>l-%AHkAj-
rj+9Pl+%-%A
p/j%+Aj+=/Pm!#%>j+.Jl+#>5>l+<j05>Ts.Pm-%Aj#%/Pl5>l
+<j
|oAj+#%Ak%-%`k=Am&PlT9G&Ak%/+%Gj-5>l+<jn
[%/3AmMA5>l+<j#%/k:H!9+A%5Gs;%Tm/.<l+%AlM+%>j+J=Am
&PlT9G.Pm3>m9/j>j&Tj/5>l+<j`jMU<l#T9G5<j+j%/Pk!+%>j+JT9G
;%Aj+%A!H+Aj+#%>l+%/PlU<l#:H!9+%>T#/k%=Am&PlT9G
#>T>j5Gs=Jj#.`k!#/Pj-%`l9`jM%>s5<j9/Pl!.A#/Pj-#!l+H/Ps=/Pj0
.Pm#/j%./l%9>Tl+!l#%Pm+Aj+#%<5<j+!mA5>l+<j`jM&Ak#/j%A#%Tk//A
#Ps+`k+%&/Pl+•Žj•5>l+<j<k#%Tk/:<l#:H!9+!s%/+%Gj-9Al/

H/Ps=/Pj+!mA5>l+<j.Pm+j#%Pm9`jMAH!k5A!AkM
€o%>j+J•Žj•5>l+<j
~o%>j+J•jl•qPj!+jo
•
Giáo trình Bảo vệ rơ le – Dự án RE II
‰o%>j+J#>l;/Pm:#A#%/Pj#=/l0%>;/Pm:#A0.>j#0+%`l-0
;/Pm:#A./PlAj-.Pm•j•0•Žj•.!m;%<&Ak%`j#9Ak;/Pm:#A+Aj+&/
3>m9/j+j+%AlM#<j#;%<Pm+j%>s3>m9/j=Aj#/j%/Pl!%AM=Aj.<l+`k
#%/Pj#
*) Phần mềm của rơle số
[Pj#+`j!-%`k+>j&Ak-%`k:Pk:+!mA+Aj+;/Pm!T9G5<j+!mA+Aj+%As
;%Aj+%A!#%>Tk+j%>sGj#.Jl#=/Pl#/P0;%</<j%A!Aj+
%As.j.Pk!;%<+%#%<=Aj/ks&Pk-%`k+>j0-%`k:Pk:+!mA%l
1.2. Áp dụng những nguyên tắc điều khiển học trong bảo vệ rơ
le
#%?//AB.`M>?/#A.•+1;%KJ#4:8#;%*/
9>E9D#%<#/#:8##%?//A,#\.*/&D/+%7.89(:&/)+
+@A#A#%/7#=L.>E+=K&)#%)#%*+!+,-./)%c
#%<#/(M.>E+3C9‘=’:"M&/#R%g.1.•#4P56#%AM.S/
!A#f##%6+%/)+@A#%/7#=L=K&)/)+5CHQ:"M&/#R%
##%/7#;709'-+%>T#$%9(:&/)++%+"+=8-%'=K&)#4/+"+
./2:;%"+%A!#9>D/./).A9(&,.b#%?/56
^M#%G;7# !K3C9‘%c#%<#/%'.>E+0=8-%'=K&)
=’T9G5]#%/7#9'-#%G.W+%>T#$%.•H6;/7#>D+.1&(5]
#"+.89P+"+-%B#C+@A5T.Y7!#%,M+B#%/7#q#%G.WH6
;/7o:i:"M+\#./)+@A#A#%/7#=L.>E+=K&)#%$=8-%'=K&)
T9G5]#!Mb9)%=’#R%/)!./b!;%/2:i:"M+\#./)g56
-%N+#4-+@A%)#%*./).>E+=K&)+e%>MP!+B!-%K/3C9‘
#%<#/:8#+"+%%A%+%1&(#/7-%' !M7#.L%+\#:"M+\#0P
%c!MP#\+./b!;%/2%f+.1&A/#I,# !A#f%’:=K

.K:569(:&/)+#*#%,#+@A=8-%'=K&)
S%E-+"+=8-%'=K&)+@A:8##A#%/7#=L+1#%2Y:,#
%/b!;%*/-%B#C+,!#4P%'#&'M0/K#%/7#’#A#%/7#=L
.>T+=K&)9(:8#.>?H`M./)"-+A0+"+;%*/-%B#C+,!#4P
=8-%'=K&).>E+/D/#%/)!%>%$%&]dd



Hình vẽ 1.1.
dv
Giáo trình Bảo vệ rơ le – Dự án RE II
[%*/-%B#C.7.>E+f/9(%c-%B#C%4M+K:%W
%'.>E+#%<#/&(+%7.89(:&/)++@A.>?H`M.>E+=K&)#h
:"M=/7HI&(#h:"M=/7./)"-[%*/+1#%2Y:n=8
9f+#%(%-%B#%N#6%L+%%AM.Y+6+0=89f+51%(/='++A0
%_+%c=8-%';%"+._+#>+%+%7.8&'%(%.>?H`M
%c/"#L+@A.4/9>E:(;%*/%'.>E+0.>E+55"%
&D/%c/"#L.•./b!+%“%+@A+"+-%B#C#%(%-%B+@A1
%c/"#L.•H/b!+%“%(M.>E+#%/7#9'-;%/#%/7#;7=K&)
%c#%<#/5A!;%/55"%.•+1;7# !K.>E+#!Mb.7
;%*/3C9‘&( !M7#.L%g
[%*/g.1&A/#I3C9‘+"+#%<#/%'.>E+-%^%E-&D/
+%>T#$%.•.>A&(#>D+.`M;%/#%/7#9'-5T.Y*/&(;%/./b!
+%“%+"+-%B#C#%(%-%B+@A+%W7!+B#%/7#g5]#!Mb
:8##R%/)!+%;%*/+%,-%(%q.</;%/+If/9(;%*/Ao.2;%*/
(M#/7%(%#%6+%/)+\#:"M+\#./)&(-%"#:8##R%/)!
#>?%E-=K&)-%N+#4-%)#%*./)%/).4/0;%*/
g-%K/#%6+%/),#%/b!#"+.8&D/+"+:4+%9/+.2#%/7#9'-
3G:n.>?H`M.>E+=K&)9(:&/)+i+%7.8;%<=$%#%>?H
:8#56+*=P(/.>?H`M%AM56+*.•3KMAAM#P.>?

H`M
*/&D/#>?%E-.B!#/P0;%*/g5].E/:8##%?//AS
.L%0.2+%56+*=P(/.>E+94/;%O/xA!.1./b!;%/256#"+
.8+@A;%*/.2."%#R%/)!
#>?%E-#%N%A/0;%*/g !M7#.L%+\#:"M+\#./)
.>?H`M&(#!Mb+%;%*/#R%/)!#>TN
2#%6+%/)%c#"+.8.•P!#P0;%*/g#%<#%>?
Y:+"+-%B#CnHI-%A0+"+-%B#C9/+&(+"+-%B#C#%?//A
[%*/+%,-%(%=AY:+"+-%B#C+@AZA0+"+-%B#C
(M-%K/.K:=K:8#+<5!,##%OA:•.2#/7%(%+\#:"M+\#&(
-%"##R%/)!
/)AM+"+-%B#C./)#C.•.>E+5CHQi+K=A;%*/+@A%)
#%*=K&)
%c-%>T-%"-NHQ.4/5*9G.•.>E+#%6+%/)&(
"-HQ#&/)+-%`#R+%&(#%/7#;75T.Y=K&)=’T9G./)#C
^:8#9W+&D/56#%6+%/)=K&)=’./)#C0=’+%!M2:4+%
#”%&&#%$>?/#A.•5CHQ:"M&/#R%.23C9‘#%<#//)+
.>A+"+-%>T-%"-&(-%>T#/)./b!;%/2%f+.•:iA:8#&/•
+K%89D#9”%&6+-%"##/2=K&)T9G
dd
Giáo trình Bảo vệ rơ le – Dự án RE II
1.3. Những kết quả đạt được trong việc thực hiện bảo vệ.
K&):8##A#%/7#=L./).I/%O/-%K/#/7%(%./b!;%/2#6
.8#"+%#A#%/7#=L=L56+*A;%O/-%4:&/+@A9>D/./);%/3!,#
%/)56+*%AM:8#+%7.89(:&/)+;%<=$%#%>?+1!M+T9(:
%O#%/7#=Lx6J+"+%#A#%/7#=L=L56+*&D/+"+#A#%/7#=L
+I94/+@A%)#%*-%K/#%6+%/)#./b!;/).25A+%+1#%2
JhA.>E+56-%"##/2+@A56+*%AM56%@MH/)#+@A#A#%/7#=L
&(#%/7#9'-#i94/:8#+%7.89(:&/)+=$%#%>?.*/&D/%)#%*
./)+I94/0.K:=K9/P#Q++!+,-./)+%5*9>E+"+%8#/P!#%Q

#*/.A+1#%2.>E+
2/K/ !M7#56+*#./b!;/)#*#%,#0569(:&/)++@A=K
&)=’T9G-%K/#%OA:•%(94#+"++%“#/P!;–#%!'#%,#.L%
1.3.1. Những chỉ tiêu kỹ thuật đặt ra đối với sự làm việc của bảo vệ
rơ le.
rTính nhanh chóng:x6+%':#]#&/)+/K/ !M7#\:4+%
+1#%2HX.7#B:#f#%P:0&(9(:#J!M%/2:H>D/#"+.8
%/)#0%_+9/P !A.7/K:./)"-09(:K%%>i.7#R%+%,#S
.L%+@A%)#%*
2#"+.8%/)#+@A%)#%*;%<9(:K%%>i.7#4
#%"/9(:&/)++I#*#+@AH`MHX0#%$H`MHX-%K/.>E+;/2:#AS.L%
%/)#&D/=/2!#%N+
x
<.
w
tgt
K
I
∞
—.`Mx
<.
r/7#H/)+B#%/7##./b!;/)S.L%%/)#;%/
\:4+%

˜
r/"#L%/)!HQ+@AHIH/)\:4+%#+%7.8S
.L%
#
#
r%?//A/K#%/7#%AM#%?//A !M.S/q>E+%/2!9(07!

+/HI\:4+%+@A+%!;a9(;%<.S/#%G#%?//A&(=’
˜
#%$5A!#%?//A##J9>EH1#OAA.W=’J9>EH
HI./)\:4+%+%!;a#%AM.S/.W%>#%6+#7`MA5A!#%?/
/A#Y#4/\:4+%o
[r’5*0&([wd‹α&D/™9(%)5*%/)#.8
7!%>#A+1n
x
<.
{xqdrdo
dt
Giáo trình Bảo vệ rơ le – Dự án RE II
q—.`Mx9(#/7#H/)+@AH`MHX0;7# !K#R%#";/%#7;–#%!'#
.*/&D/+%7.89(:&/)+=$%#%>?o0#%$+B#%/7#%K//K:x
<.
.7#/7#
H/)x.2#/7#H/)x.K:=K.>E+#R%S.L%%/)#;%/\:4+%2
.>E+%>&'M0#A#%,M-%K/9(:5A/K:.>E+#%?//A#
#
3!*+%
.7;%/#A%'.>E+x
<.
wx
/)+/K:/"#L#
#
 =A%(:‘%”A-%K//K:#%?//A/K/
!M7#56+*0#N+9(.I/%O/:8#56#"+.8,#%A%+@A=K&)
x6;FH(/#%?//A/K/ !M7#56+*\:4+%5]HX.7./)
"-/K:;FH(/0#N+9(+1#%2`MP%c;%1;%J##6;%i/
.8.8+T./)+@A%8#/P!#%Q%AM+@A+"+#!#`:./)##?/

/A=L;FH(/(M
7!&/)+/K !M7#\:4+%;%<.>E+#%6+%/):8#+"+%
%A%+%1#%$#$%#4/K:./)"-5]=L;FH(/0H&'M0.8+T
./);%<.Y=85]/K:%A%5*&I !AM%_+=Lh%(
#(I;%/./)"--%Q+%Y/#i94/#%$;%1+1;%KJ#6;%i/.8n
&$’HI./)#6;%i/.8#J9P+A0#S#%,#./)"-T/#P
:4+%+!+,-+@A.8+T+1/"#L9D0H.1./)"-#4/+"++6++@A
.8+T#iP;%<#%OA:•.2.8+T;%i/.8.>E+
R%%A%+%1+IK%%>i.756S.L%+@A%)#%*n
7!56\:4+%+(.>E+/K !M7#%A%+%1#%$;%KJH!M#$
56S.L%+@A%)#%*+(.>E+.K:=K
%G !A./2:&b#R%%A%+%1#%$=K&)T9G=’./)#C
#%6+%/)%A%+%1%T=K&)T9G=’./)+T0H94/#h.>E+
!"#R%+@A+"+-%B#C#+%!M2.8%?//A#"+.8/P
+@A=K&)=’./)#C,#%O>?/#A#%6+%/)=K&)=’T9G
./)#C&D/#%?//A#"+.8v‰:5q#R%#h9W+.4/9>E.>E+;/2:#A
./ !A>š.•.>E+3"+.L%.79W+#!Mb#R%/)!:i:"M+\#o
/D/%4#*/.A+@A#*+.8."-N##%6+#7#^M#%!8+&(+%7.8
!".8+@A:"M=/7HI%AM+@A%c-%B#C;%"+
rTính lựa chọn:/)+3C9‘#*#%,#.*/&D/#$%#4\:4+%
=A%(:+"+‘%”A9(n+%“h+!+,-./)+%:8#5*9>E#*/
#%/2!+"+%8#/P!#%Q%’::Q+.R+%.10=K&)-%K/.>E+96A+%f&(
5(9f+%c#%/7#=L56+*&(+%“\#A;%O/:4+%%c#%/7#=L
(Mg&'M+%“:i:"M+\#./)i%c:"M+\#./)B%,#0+I
%c#%/7#=L;%\++@A%)#%*./)#>TN-%K/#/7-#6+9(:&/)+
RHQi%)#%*./)96+%$%drt07!\:4+%3!,#%/)i./2:[
#%$%c:"M+\#./)d&(|-%K/:iA0H&'M.>?H`Mr|5]
;%<+1HI./)./ !A05#4:&X-%K/.>E++!+,-./)
g&'M05T.Y%$%drt-%K/.K:=K.>E+ tính chọn lọc #N+9(=K&)
+@A9>D/./)-%K/#/7%(%+%“./b!;%/2:i:"M+\#d&(t:(#%</0

d|
Giáo trình Bảo vệ rơ le – Dự án RE II
+I:"M+\#|&X-%K/.194/.2H!M#$%4#.8+@A.>?H`Mr€
+!+,-+%#4:
Hình 1-2
#>?%E-=K&)-%N+#4-%>=K&);%K+"+%0&/)+
96A+%f9(H;%*/g3"+.L%#>?%E-=K&).T/K#A
+1#%2+1.>E+#R%96A+%f#%< !A%c-%B#C+T=Kq&RHQ%>
.>A#%P::8#5*:4+%#$%•&(oZ(#%c#>?%E-
%>&'M.•%M5/%#R%%A%+%1
#%6+#7+1%/b!#>?%E-+Q#%2-%K/3"+.L%#%N#6>!
#/P !A#f/cA%A/+%“#/P!;–#%!'#+1%/b!:`!#%!X%A!n#R%
+%f9f+&(#R%%A%+%17!#A3"+.L%#R%%A%+%19( !A
#f%T0&'M#%$#4:#%?/+%,-%':i:"M+\#;%<+%f9f+
#>?%E-(M-%K/%/)!+%“%94/569(:&/)+%A%+%1+@A=8.1
94/#6.8N+9(#:8#;%K#%?//A,#\0=8-%'.194/
#6.8#6.85]#/7%(%./b!;%/2#6.8.2#%/7#9'-569(:&/)+
#i94/+@A%c#%/7#=L&hA=L#"+%A;%<+%f9f+!*/+^+%“.2
+"+#%/7#=L=L56+*h%4#.87!./b!;/)%A%+%1;%<
.>E+>!#/P%A.B!#%$+1#%2+%,-%':8#;%K#%?//A#$
%•(.1.2/K/ !M7#56+*#%G./b!;/)+%f9f+
K&)=’./)#C+1#%!'9E/9(n+%#A:8#5*9>E._+#R%
.80,#+B#%/7###>?%E-=K&)-%N+#4-/b!(M5]1-
-%B&(&/)+#R%#"0.K:=K#R%+%f9f+#%c./b!;/)#*#
%,#
-Tính đảm bảonR%.K:=K569(:&/)++@A=K&)9(9!<9!<
#"+.8;%/+B#%/7#&(+%“;%/+B#%/7#:(#%</q#N+9(.K:=K;%<
#"+.85A/0%_+#"+.8;%<.W9W+;%/;%<3!,#%/)56+*
.*/&D/#A#%/7#=L.>E+=K&)o
2.4#.>E+#R%.›:=K+@A569(:&/)++@A=K&)#%$+B-%K/

+1%A/./b!;/)n=K&)-%K/.>E+#%/7#;7.Wq#%G !A./2:+@A5T
d€
Giáo trình Bảo vệ rơ le – Dự án RE II
.Y0+@A#R%#"/"#L./b!+%“%&&œo&(#A#%/7#=L;–#%!'#-%K/
+1:N+.8#/+'M+A
$3"+3!,#56+*+@A#A=L./)#J9P#%G5*9>E-%B#C
+,!#4P10H.1.2.K:=K;7# !K9(:&/)+#*#0MP!+B!+%“+1
:8#5*9>ER#+"+-%B#C+,!#4Ph.`MW#A.>E+/K-%"-#*#
%,#0##%/7#;7#%G !A./2+@A#R%.K:=K9(P#%/7#;75A
+%+%“H^:8#5*9>E#*/#%/2!+"+-%B#C+,!#4:(#%</
2.4#.>E+.8#/+'M+A0#A+B5CHQ+"+-%B#C#%(%-%B
&D/+%,#9>E+A0+I&/)+&'%(%#A#%/7#=L.>E+=K&)-%K/i
#%c./b!;/)#*#%,#
x&D/=K&)H^T9G./)+T0=K&)H^T9G./)#C+1#R%
.K:=K+A%T0H;%<+1+"+-%B#C+%!M2.8%'#&'M0T9G
./)#C;%<+1HA.8!P;%<+I#4P%c#"+.8
5A/%>.•3KMAiT9G#/7-./2:>T#65&D/T9G./)+T0T9G
./)#CR#+%L!K%%>i+@A&A.'-+T;%R%AM+1=Q/#;%<;%R
!S/#%f+@AT9G./)#C+A%Tx*9>E9B#"+.8+%,-
%'.>E++@AT9G./)#C9D%T5&D/T9G./)+T0.Y#%?/%L-
./)!#"+.8+%-%F-+@AT9G./)#C9D%T0&$&'M56#i&b+@A
T9G./)#C%A%%T
-Độ nhậynK&)+1.8%'M+(+A7!1#"+.8i.85A/
9)+%+(%O5&D//"#L.L%:N++@A#%<5*.>E+;/2:#AqHI
./)0./)"-&&o8%'M.>E+."%/"=’%)5*.8%4MRHQn
.*/&D/=K&)HI./)+6+.4/0=K&)5]#"+.8;%/#JHI./)
!":8#/"#L.•3"+.L%)5*[
%4M 
.>E+3"+.L%=’=/2!#%N+
5A!n

[
%4M
w
IkdBv
I
ngm :/
qdrto

::/
n9(/"#L%/)!HQHI\:4+%%O%,#+1#%2.>E+0
i#%?//A=’#%?//A#"+.8+@A=K&)

;. 
ngI./);%i/.8+@A=K&)q=K&)#"+.8iHI
./)(Mo
*/&D/%c94/=K&);%"+0%)5*.8%4M.>E+.L%%”A
;%"+&D/.8%4M#+<#%N+qdrtoRHQ0.*/&D/=K&);%K
+"+%0%)5*.8%4M.>E+._+#>=i/ !A%)/cA%A/#S#i
u!M.L%%/)%(%i.4/.A5*+"+>D+.bA%c/"#L#*/
#%/2!+%-%F-.*/&D/%)5*.8%4M+@A%c94/=K&);%"+%A!0
&(&D/%c#%/7#=L.>E+=K&);%"+%A!/"#L(M9!<9D%Td
&(#%>?9,Mi/cA;%Kdt&(th !A%)qdrto+%#%,M0.2.4#
d~
Giáo trình Bảo vệ rơ le – Dự án RE II
.>E+/"#L.8%4M+A0#N+9(=K&)+1.8%4M+A#%$HI./);%i/
.8
;.
;%<.>E+B=’/"#L
::/
q&$7!

;.
w
::/
0#N+
9(%)5*%4M;%<+I9D%TdoA#%hA%'56=K&)HI./)
+N+.4/;%<3KMA;%/#A+1n

;.
•
.:
qdr|o
(+e;%<=A/?#%6+%/).>E+;%/
;.
•
-#:A3
qdr€o—
.`M
.: 
&(
-#:A3
9(HI./).L%:N+&(HI./)-%Q#K/9D%,#
##A#%/7#=L.>E+=K&)$=K&)5];%<#"+.8#+%7
.89(:&/)+=$%#%>?0+%7.8.L%:N+%AM+%7.8-%Q+#K/:A30P
+B-%K/+%,-%'n

;.
{
-#:A3
qdr~o
u!A%)qdrto&(qdr~o+%#A#%,Mn#A5]%'.>E+:8#.8%4M

+A;%/=K&)#"+.8i/"#L%O+@AHI./)+1/"#L=$%
#%>?q#+%7.8=$%#%>?o%'#&'M0i=/2!#%N+qdrto/"#L
[
%4M
+(#J;%/HI;%i/.8
;.
+(%O0+I !A%)qdr~o#%$
+%“A’%c/"#L%O%,#+%-%F-.*/&D/HI;%i/.8
;.
9(%c/"#L,#BHI./)-%Q#K/:A3q
-#:A3
o&(+A%T/"#L
(M:8#R#'M=K&)5]#"+.8iHI./);%i/.8+1/"#L9D
%THI./)-%Q#K/:A3;%<%/b!2=K&).4#.>E+.8%4M#%$
+"+T9G+,!#4P=K&)-%K/#/P!#%Q:8#+<5!,#R#%,#.2#"+
.8'M%cT9G(M-%K/,#%4M7!+<5!,##/P!#%Q+@AT9G
:(9D#%$T9G5]#"+.8i.85A/9)+%+@A+"+#%<5*;/2:#A9D
q5&D//"#L=$%#%>?o0H&'M.8%4M+@A=K&)5]/K:
"+T9G./)#C#/P!#%Q+<5!,#,#R#5&D/T9G./)+T0&$&'M
P+1:8#.8%4M,#+A8%4M+@A=K&)./)#C#JH&'MT9G
./)#C5]+1:8#%)5*#i&b#*#%T%)5*#i&b+@AT9G./)+TqBd
.T&Lo
)5*#i&b=/2!#%L !A%)/cA/"#L#i&bq/"#L+@A#%<
5*.>E+;/2:#A:(i/"#L.1T9G.>A#i&b#4#%"/%“o&(/"#L
;%i/.8q/"#L+@A#%<5*.>E+;/2:#A:(#4//"#L.1T9G#"+
.8x6;/)(M.>A.7/K:HI./);%i/.8o—T9G./)#C%)
5*#i&bBd.T&Lx6;/)(M1--%B.>A.7/K:HI./)
;%i/.8%'#&'M0:!*#J%)5*[
#&
(M.7/"#LB:8#.T&L

#%$#%$-%K//K:HI./);%i.8+@A=K&)
;. 
0./b!(M#>T
N&D/&/)+#J%)5*%4M
q&$[
%4M
w
IkdBv
I
ngm :/
o
[R+%#%>D+=A=$+@AT9G./)#C#%>?+%“=F=’d‹|%_+
d‹€5&D/;R+%#%>D+=A=$+@AT9G./)+Th.`M+%#%,M&/)+5C
d‰
Giáo trình Bảo vệ rơ le – Dự án RE II
HQT9G./)#C+%-%F-/K::8#5*9>E.";2+"+=K\+"+
#%/7#=L=K&)g&'M0;R+%#%>D++@A/AH/b!;%/2#!/A+e
.>E+/K:
Độc lập đối với điều kiện vận hành:K&)-%K/.>E+#%/7#;75A
+%.K:=K#"+.8.W;%/3!,#%/)56+*i#%/7#=LH>E+=K&)
2.K:=K./b!;/)(M#%$%c/"#L;%i/.8-%K/.>E+
#R%#"H6A#P+"++%7.89(:&/)+max &(min +@A#%/7#=L.>E+=K
&)%>&'M#A-%K/;/2:#A56#"+.8.W+@A=K&)i+K%A/+%7.8
#P#N+9(.K:=K.>E+MP!+B!.8+9'-.*/&D/./b!;/)&'%(%
T9G./)#C+1:8#>!./2:9(+1HK//"#L./b!+%“%80.Y#%?/
,#.T/K.*/&D/=8-%'#%6+%/)./b!+%“%
1.3.2. Các yêu cầu khác đặt ra đối với bộ phận bảo vệ.
a) hiệu quả kinh tế:[%/96A+%f+"+-%>T"#*#%,##
#%/7#;7=K&)=’T9G0+%W#A;%<+B+%W‘.7M7!#*;/%#7&b
.B!#>=A.B!&$’55"%&D//".B!#>+@A#A#%/7#=L.>E+=K

&)#%$/".B!#>.*/&D/#%/7#=L#"+.8=K&)%O%T%/b!
#R%#";/%#7#A+B#R%#".7%c#/P!#*#=K !K0=K
H>Z&(;/2:#A3G:3F#.L%;a
K&)=’T9G./)#C+B#%/7#%>#%A#"+=KH>š,#
.T/Kq5&D=K&)=’T9G./)#ho0&$;%<+B;/2:#A09(:
54+%%AM#%AM#%7:8#5*#/7-./2:x#$%.8%/)-&Q+@A>?/
=KH>š-%K/+A.*/&D/#>?%E-=K&)=’T9G./)#C<
#"+=KH>š+"+#%/7#=L=K&)=’T9G./)#C#%$%ž%(%T
%/Ÿ!0&$#/7%(%+<#"+(M#P:4+%/&(#P%c:H!9#%"
9\-.>E+
b)Kích thước bao bì giảm:

,.b(M !A#f#./Ÿ!;/)
%/)AM0._+=/)#9(;%/=*#Ri+"+-%I./b!;%/2#!#`:
c) Sự linh hoạt trong thay đổi đặc tính động: K&)./)#C+1;%K
J#%AM.S/._+#R%#"+.8##>?%E-=K&)-%N+#4-0.`M9(
:8#>!./2:/b!(M+19E/9(+^:8#9W+#%/7#=L=K&)+1#%2"-
HQ+%%c#A#%/7#=L.>E+=K&);%"+%A!:(+%W+B
%c._+#R%#"+.8;%"+%A!*/&D/T9G./)+T0;%KJ#%AM
.S/(M=L/D/%4RHQ0i:8#5*94/+@A=K&);%K+"+% !A
#!/A+@A:8#5*=8+%!M2:4+%0#A+1#%2H?/+%!M2._+#R%
&I#I—=K&)./)#C0;%KJ=/7.S/+"+.>?._+#R%#%G
+%/b!::!*#%>?,#80+I%c=8-%'+B#%/7#.2-%Q+
&Q+%:Q+.R+%(M#%$.T/K
d) Tiêu chuẩn hoá các tổ hợp:—T9G./)#C&/)+#/P!+%!›%"
+1%c>!./2:.";2%'#&'M0;%/.1&/)+9\-"-&(&/)+;/2:#A
dŠ
Giáo trình Bảo vệ rơ le – Dự án RE II
+"+T9G.>E+#%6+%/)#%c./b!;/)#*#%T0%c#%A#"+
=KH>šH•H(%TI;%/=L56+*#%$+1#%2%A%+%1#%AM

#%7+"+#S%E-=L56+*
/)+xCHQ+"+:4+%/#P+"+=K:H!9#4P#R%HK:
=K+A%T&$94/A.>E+%c5A/-%4:+1#%23KMAH+"-*/
1:94/#h&/)+-%`#R+%+"++%“#/P!;–#%!'#&(+"+MP!+B!;%"+
._#A.*/&D/569(:&/)+&(#%6+%/)=K&)+@AT9G0#A#%,M’n=K
&)./)#C#%6+%/)=’+%,#="HXq+I+1#P=K&)#”%0#>T
N&D/+%!M2:4+%#”%&$;%<+1%c#/7-./2:+T;%R&(%c
-%B#C+%!M2.8o#%K:•%c+%“#/P!;–#%!'##./b!;/)
#*#%,#&(#%/b!#>?%E-+1%/b!>!H/2:%T5&D/T9G./)
+T$#%71/K/#%R+%.>E+#4/5A(MAM>?/#A#%R+%H^=K&)
=’T9G./)#C%T&(HBHB1#%AM#%7+%T9G./)+T
1.4. Sơ đồ cấu trúc của bảo vệ
#>?%E-=K&).T/K0%’:;/2:#A56#%AM.S/+@A
:8#.4/9>E(.15&D/:8#/"#L:*+q/"#L !M+%/7!o%>9(
=K&)HI./)0=K&)./)"-0.>E+#%6+%/ž=’T9G./)+T#%$
>?/#AH•H(H^5T.Y./)!MP#\+.2=/2#%L5T.Yq+If/9(
5T.Y+%R%o/b!(M#%6+%/).>E+&$5*9>E:4+%&(%c-%B
#C+,!#4P+IR#P;%<+B#%/7#5T.Y#/2;%A/
#>?%E-=K&)-%N+#4-0MP!+B!-%K/55"%%A/.4/
9>E#%G=/P.8%AM569)+%-%Aq%>=K&)+1%>D059)+%0
;%K+"+%o&$15]#"+.8;%/;7# !K%'.>E+#h5655"%
&>E# !":8#/"#L/D/%4(.10#N+9(5T.Y+1#%2=/2!#%L:8#
:N+.8-%N+#4-+A%T .</;%/:V/:8##%A/.4/9>E.>E+5
5"%94/.*/+%/7!&D/:8##S%E-+"+.4/9>E;%"+h.1;%/%c
=K&)-%N+#4-#%6+%/).*/&D/T9G./)+T0>?/#A5]H^5T.Y
#/2;%A/.2=/2!#%LxT.Y#/2;%A/(M+%-%F-#%GHZ/:4+%H•
H(%T
&(5T.Y9\-"-—5T.Y=*#R0%c:*/ !A%)/cA+"+-%B
#C+1#%2;%<.>E+-%K"%:8#+"+%.BM.@:(+%“#%2%/)%)
#%*=K&)+@A:8#5*%,#.L%#A#%/7#=L.>E+=K&)=’+"+%

5CHQ;‘%/)! !M.L%+@A%(>D++"+5T.Y9\-"-0:*/
9/P !A.>E+#%2%/)#%G%c !!M.L%.•3"+9'-.*/&D/#,#+K
+"+;%R+Q&(#A#%/7#=L./)(/5T.Y!MP#\+0i=K&)T9G
>?/#A+IH^5T.Y=*#R
xT.Y!MP#\++1#%2H^.2#S%E-%c-%B#C#%(%
-%B+@A=K&)./)#C0.*/&D/#>?%E-=K&).T/K—#>?
%E-+"+=K&)-%N+#4-05*9>E+"+:4+%./)+1#%2,#%/b!0H.1
dŒ
Giáo trình Bảo vệ rơ le – Dự án RE II
5]#4A%c;%1;%J#&/)+#%2%/)#(=8#S%E-#P+^
:8#=K&](&/)+#%GHZ/5T.Y+e,#;%1;%J
$#%7.*/&D/=K&)./)#C-%N+#4-#%$-%K/+1:8#94/5T.Y
;%"+&D/94/5T.Y.•P!—5T.Y(M0%c-%B#C9(:&/)+.>E+
#$%=(M=’+"+%$%+%c%'#0+I+"+#R%/)!#!Mb/cA+"+-%B
#C.>E+-%K"%=’+"+:e/#P%c5T.Y94/(M/D/#%/)!:8#
+"+%Z(+,!#W++@A#(=8#S%E-+@A=K&)0.Y#%?//W-#A
#%GHZ/56#"+.89/P#/7-:(%c-%B#C;%"+%A!.•#%6+%/)
;%/=K&)%4#.8
%G !A./2:&b%c94/-%B#C.>E+5CHQ#+,!
#W+0#%$=K&)=’./)#C+1#%2-%`#%(%=K&)&D/%c-%B#C
9/+&(=K&)&D/-%B#C#>T#6—:8#5*#>?%E-0#+^
:8#5T.I+1#%2.>E+NHQ+K%A/94/-%B#C#P
1.4.1. Các phần tử logic trong sơ đồ bảo vệ bằng điện tử.
K&)T9G5]#"+.8;%/-%"#%/)#%,M56/".4i=/P.8
%AM569)+%-%A.>E+;/2:#Ax6/".4=/P.8=/2!#%LH,!%/)!
3!,#%/):8#56+*
/)+;/2:#A56/".4(M+1#%2#%6+%/)%?+"+-%B#C
9/+5T.Y=K&)0._+=/)##;%*/3C9‘&( !M7#.L%g
q%$%•rdo>?/#A5CHQ%c-%B#C9/+:(1#%6+%/)+"+
+%N+J9/+%>.•=/7##.4/5*9G0.19(+"+%(:+T=K

5A!n¡000[¢£¡0[¢£0œ—+"+
-%B#C(M0%c=/7#%/PiZ&(&(ZA+%“+1#%2+1%A//"
#L+@A.4/5*9G0#%<#%>?;‘%/)!9(¤v‚&(¤d‚
P+4%%c-%B#C9/+%>.•P!#P0#5T.Y=K&)
T9G+I5CHQ8•/%c=89/++1#P9(=8-%`=/)#—%c
-%B#C9/+(M0=/75*&(+156=/7.S/9/P#Q+&(+1#%2+1:8#5*
9>E&<#'+"+/"#Lq=AY:#/D/%4:8#HK/%,#.L%o#
;%/=/7+*ZA+%“+1#%2+1%A//"#L¤v‚%_+¤d‚*/&D/-%B#C
(M0:<#K#"%f++@A569(:&/)+.>E+#%6+%/)%?9/+%(:
$+"+.4/9>EZ&(+1:8#/"#L9/P#Q+0+I.4/9>E.B!
A+%“+1%A//"#L0=8-%`=/)##%6+#79(%c-%B#C9A/
2+1#%2HI#$:%c/".4#56=/7.S/+@A=/P.8
%AM569)+%-%Aq&$56/".4=/2!#%L3!,#%/)56+*oP#%6++%,#
T9G#%6+%/)+%N+J=8-%`=/)#g.1##%6+#7%c-%B
#C%F-9A/;%<#%2&\:_##5T.Y=K&)./)#C
x5"%&D/:8#5*-%B#C#>T#60-%B#C9/++1>!./2:9(
.K:=K569(:&/)+#*#+@A#A†/#0&$%c#A†/#(M9(:&/)+i
+%7.8+%!M2:4+%#5T.Y-%B#C9/+>T#6K%%>i+@A
d•
Giáo trình Bảo vệ rơ le – Dự án RE II
56#%AM.S/%/)#.8.*/&D/569(:&/)++@A#A†/#i+%7.8+%!M2
:4+%#%$R#%TK%%>i+@A56#%AM.S/%/)#.f#+%7.8-%B#C
#>T#6
1.4.2. Những phần tử tương tự trong sơ đồ bảo vệ điện tử.
¥#%T5&D/%c-%B#C9/+5*%c-%B#C#>T
#6#!M7#R%&(;%<#!M7#R%0+%W#A#%>?_-#=K&)./)
#C%e=8-%'5A!n=8;%!7+%.4/0;%!7+%.4/#%!'##"9(:&/)+%>
:8#=8+80=8#R+%-%`&&œ-%B#C%`=8/0-%B#C9)+%-%Aœ
:8#5*#>?%E-0#+^:8#5T.Y=K&)#A&hA_-
-%B#C9/+&hA_--%B#C#>T#6%'#&'Mn.4/9>E;7# !K#h

5655"%+@A:8#5*=/P.8%AM.89)+%-%Ar5655"%.>E+#%6+
%/)=’+"+-%B#C9/+r.>E+;%!7+%.'/=’:8#;%!7+%.4/
#A†/#q-%B#C#>T#6o&(5A!.194/.>E+#!Mb !A+%+"+-%B
#C#/7-#%G+@A5T.Y
8-%';%!P+%.4/#!M7#R%&(+"+=8-%';%"++@A-%B#C
#>T#6#5T.Y+B-%K/.>E+96A+%f+›#%'#%G !A./2:.8
+%R%3"+&(;%<9(:#%AM.S/._+#R%$’%c5A/5*+@A
%c-%B#C(M+1#%2.>A.7K%%>i;%<#*#.*/&D/;7# !K
+@A=K&)
1.5. Bảo vệ chính, bảo vệ phụ và bảo vệ dự trữ.
[%/#%/7#;7=K&)=’T9G+%+"+#A#%/7#=L%)#%*+!
+,-./)0+%W#A+BH6;/7.7#>?%E-3,!%,#9(n;%/3!,#%/)
56+*=P##%/7#=L#%$#%/7#=L(M;%<.>E+#"+%A;%O/%)#%*
./)%>&'M56+*&X#/7-#Q+.>E+H!M#$&(+(#iP#B:#f
2.b-%I%/)#>E(M#%$=P+4%=K&)+%R%>?/#A+IH6
;/7#%G:=K&)H6#cK&)H6#c5]#"+.8##>?%E-=K
&)+%R%#h+%*/#"+.87!:"M+\#./)+@A#%/7#=L.>E+=K&)
;%<#/7%(%\#0#%$=K&)+@A-%B#C=P+4%-%K/#/7%(%94/
#h&^56+*A;%O/9>D/./)=K&)+@A-%B#C=P+4%(M5]#/7
%(%./b!;%/2:i:"M+\#./)+@A1g.15]>+!+,-./)
+%-%B#C=L56+*#h:f/-%RAZA=K&)+@A+"+-%B#C=P
+4%9(=K&)H6#c.*/&D/-%B#@G:(:"M+\#+@A1.•;%<#/7
%(%\#.>E+%>.•P!#P
K&)+%R%#A#%/7#=L9(=K&)#%6+%/)#"+.8%A%;%/
56+*5KMA#-%4:&//D/%4.*/&D/#A#%/7#=L.>E+=K&)
I=K&)H6#c.*/&D/+^#A#%/7#=L(M9(=K&)#%AM#%7+%
#"+.8+@A=K&)+%R%##>?%E-=K&)+%R%#h+%*/;%<
#"+.8%_+##>?%E-=K&)+%R%.A##>?%E-#/2!
#!%AM5CA+%cA%OK&)H6#c+B-%K/#"+.8&D/:8##%?//A
tv

Giáo trình Bảo vệ rơ le – Dự án RE II
9D%T#%?//A#"+.8+@A=K&)+%R%.2+%=K&)+%R%#%6+
%/)%/):&Q+@A:$%9(94/-%›#C=L56+*A;%O/:4+%#>D+#/P
q;%/=K&)+%R%9(:&/)+.Wo
 !"#$%%/P+N!=K&).*/&D/+"+-%B#C;%"+%A!
+@A%)#%*./)0=K&)H6#c+%=K&)+%R%+1#%2.>E+.K:=K
#%G=A+"+%5A!n
Ao K&)+%-%B#C=P+4%q=K&)(M.>E+f/9(H6#c
;%K+(+%o
=o K&)-%Q._##P+^-%B#Cq=K&)(M+1#P9(H6#c
#4/+%Vo
+o U8#T9G-%Q.>A&(#5T.Y=K&)+%-%B#C=P
+4%0T9G(M5]./b!;%/2:i:"M+\#+@A-%B#C:(#A !A#`:
1:8#5*#>?%E-=K&)+%R%;%<.K:=K=K&)#(=8
+%/b!H(/+@A:4+%+B#%/7#=K&):(5]+1:8#5*.4.>E+f/9(
&^+%7#+@A=K&)+%R%0&$7!56+*3!,#%/)#4/&^+%7#(M#%$
=K&)+%R%5];%<\:=\#.>E+&(H.115];%<#"+.82
+1#%2.K:=K=K&).*/&D/+"+56+*3!,#%/)#4/&^+%7#(M
>?/#A._#:8#94/=K&)+1#P9(=K&)-%Q
—:8#5*#>?%E-+Q#%20=K&)H6#c+1#%2#%K:•&A/#I
+@A=K&)-%Q+@A-%B#C#>TN
1.6. Những loại bảo vệ chính bằng rơle.
1.6.1 Bảo vệ dòng điện: K&)HI./)#"+.8##>?
%E-HI./)+@A:4+%=K&).>E+#J9PH !"#K/%AM\:4+%
%c=K&)(M#%6+%/)=’T9G+>?.8q+If/9(T9GHI
./)oT9G5]#"+.8;%/HI./)#:4+%.>E+=K&)&>E# !"
:8#/"#L%,#.L%.•.>E+#%/7#9'-gI./)(Mf/9(HI./)
;%i/.8qHI./)#"+.8o+@A=K&)&(;‘%/)!9(
;.&
/"#LHI./);%i/.8+@A=K&)9(/"#LHI./)+@A

:4+%.>E+=K&):(i/"#L.10=K&)9(:&/)+q+If/9(=K&)#"+
.8o0#>TN&D/T9GHI./).1#/7-./2:+@A:$%q#
#>?%E-T9G+1#/7-./2:o/"#LHI./);%i/.8+@AT9G
.>E+.L%%”A%>5A!n

;.
w
TC
n
IkdBV
qdr‰o
—.`M
+
9(#“5*=/7.S/+@A:"M=/7HI+!+,-HI./)
+%T9G%>&'M0=K&)HI./)5]#"+.8;%/#%OA:•./b!;/)n


{
;.&
qdrŠo
td
Giáo trình Bảo vệ rơ le – Dự án RE II
—.`M9(HI./)+@A:4+%.>E+=K&)%c=K&)(M
+If/9(94/=K&)+6+.4/$’0=K&)HI./);%<#"+.8
#+%7.89(:&/)+=$%#%>?0P/"#LHI./);%i/.8+B
-%K/9D%T/"#LHI./).L%:N+
.:
0

.Y#%?/+e9D%T/"

#LHI./)+6+.4/+@A-%Q#K/0#N+9(n

;.&
{
.:
qdrŒo

;.&
{
:A3
-%Q#K/
K&)HI./)+6+.4/9(:8##%c=K&).T/K%,#
H^T9G=K&)
1.6.2. Bảo vệ điện ápnK&)./)"-+1t94/n6+#/2!&(+6+
.4/
a) Bảo vệ điện áp cực tiểun9(=K&)5]#"+.8##>?%E-
./)"-/K:./H5!,#%/)HI./)\:4+%T9G./)"-+6+#/2!
5]#"+.8;%/./)"-+@A:4+%.>E+=K&)/K:.7H>D//"#L.•
.>E+#%/7#9'-.2=K&)#"+.8/)"-.>E+#%/7#9'-(Mf/9(./)
"-;%i/.8+@A=K&)n
;.&
N+9(:!*#"+.8+B#%OA:• !A
%)5A!n
 •
;.&
qdr•o
2=K&);%<#"+.8#+%7.8=$%#%>?0#%$./)"-
;%i/.8-%K/%O%T./)"-.L%:N+
.:
&(%O%T./)"-+6+

#/2!+1#%23!,#%/)# !"#$%&'%(%
:/&'%(% 
i+%7.89(:
&/)+=$%#%>?0#N+9(#%K:• !A%)5A!n

;.&
•
.:
qdrdvo

;.&
•
:/&'%(%
/)"-;%i/.8+@AT9G.>E+.L%%”A%>5A!n

;.
w
nTT
Ukđkđ
—.`M
 
9(#¦5*=/7.S/+@A:"M=/7./)"-+!+,-+%
T9G
b)Bảo vệ điện áp cực đại: .>E+#%6+%/)=’T9G./)"-+6+
.4/%cT9G./)"-+6+.4/5CHQR#%T%cT9G./)"-+6+
#/2!qi:"M-%"##%@M./)0i.>?H`M./)"-,#+Ao%cT9G
./)"-+6+.4/5]#"+.8;%/./)"-i%c+6++@A:4+%./).>E+
=K&)#J9P !"./)"-;%i/.8+@A=K&)0#N+9(#>TN&D/
;%/3KMA !A%)5A!n
tt

Giáo trình Bảo vệ rơ le – Dự án RE II
{
;.&
qdrddo
2+%=K&);%<#"+.8#+%7.8=$%#%>?0#%$+e
#>T#6%>+"+#>?%E-#P0#A-%K/.K:=K !A%)5A!n

;.&
{
.:
qdrdto

;.&
{
:A3&'%(%
.1
:A3&'%(%
9(./)"-+6+.4/+1#%23!›#%/)# !"
#$%&'%(%i+%7.8=$%#%>?#4/%c+6++@A:4+%.>E+=K
&)
K&)=’T9G./)"-+6+.4/3CHQ/(%+%=K&)&D/=8
9f+i#:8#5*:4+%+@A%)#%*J9>E
1.6.3. Bảo vệ có hướng:
K&)+1%>D#"+.8;%/3!,#%/)56=/7.S/ !A#f
+@A9)+%-%A/cAHI./)&(./)"-+@A:4+%.>E+=K&)RHQn
#>?%E-.>?H`M+!+,-#h%A/-%RAq%$%dr|o0+K%A/#!#`:

d 
&A
t

i+%7.89(:&/)+=$%#%>?+!+,-+%+"+%8#/P!#%Q
.>E+*/.7+"+#4:00&A
$%)#%*./)9(:&/)+iHI./)3AM+%/b!0+%/b!+@A1
#%AM.S/5A!:V/="+%!;a0H&'M;%<#%23"+.L%i:8#+%/b!
HI./)+%4M%,#.L%:(+%“+1#%23"+.L%i569)+%-%A+@AHI
./)5&D/./)"-#4/%c./2:;%"+%A!+@A%)#%*./)

 
Hình 1-3a
Hình 1-3b
t|
Giáo trình Bảo vệ rơ le – Dự án RE II
&/)+%/P+N!=K&)=’T9G0#%G !M>D+0+%W#A
%/:8#+%/b!%,#.L%+@AHI./)#4/%c./2:;%"+%A! #%6+#7
1+1/"#L#4/:8#./2:%,#.L%[%/HI./)3AM+%/b!#%AM.S/
#%$#$%%$%(M+e5]=/7.S//b!(M5KMA#%G+%!;a0#%G !M
>D+0:e/#P#%§+1#%2;‘%/)!HI./)#>TN&(9(.4/9>E
-%N+q;%<-%K/9(.4/9>E#N+#%?/o$%=Pqdr€Ao/D/#%/)!=/2!
.Y&F+#T+@A./)"-&(HI./)i./2:#+%7.89(:&/)+=$%
#%>?569)+%-%A/cAHI./)&(./)"-.>E+3G:%>9(H>T
;%/&G+#T./)"-&>E##>D+&G+#THI./)0#N+9(¨
d
{v
Hình 1-4
[%/3!,#%/)56\:4+%#P.>?H`M£d0#4/./2:[
q%$%dr|=o=/2!.Y&G+#T+@AHI./)&(./)"-i#4/+^./2:5]
+1%$%dr€=03!,#%/)569)+%-%A¨
t0 
#%<#%>?569)+%-%AAM
;%"+&D/569)+%-%A¨

d
:8#1+B=’dŒv
v
%W#A+e+1#%2
3G:%>9)+%-%A¨
d
##>?%E-AMHI./)./#>D+./)"-0
#N+9(¨
t
•v
A+e#%,M’0#h+%7.89(:&/)+=$%#%>?.7+%7.856
+*#P.>?H`Mrd0.•3KMA56#%AM.S/.";2+@A-%AHI./)
5&D/-%A./)"-i#4/:8#.B!+@A.>?H`M=L56+*>?/#A5C
HQ56;/)(M.2#4P56#"+.8+@A=K&)+1%>D%G !M
>D+0;%/\:4+%#4/./2:[#%$i./2:#P5T.Y%$%dr|=5]=/2!
#%L:8#:e/#P+1+%/b!>E+&D/+%/b!/D/#%/)!i%$%dr|A
7!56+*3KMA#P.>?H`M£t#%$5]3!,#%/)56#%AM.S/
.";2.*/&D/-%A+@AHI./)#4/./2:z0&(+e#%G+"+% !M>D+
%>&'M0#A+1#%2=/2!#%L=’:e/#P./#h./2:z#%G+%/b!>E+
94/&D/+%/b!+@A+%7.89(:&/)+=$%#%>?
t€
Giáo trình Bảo vệ rơ le – Dự án RE II
%>&'MZ(0+%“+1#P.>?H`M=L56+*.•3!,#%/):8#
56=/7.S/ !A#f+@A-%AHI./)i:8#.B!.>?H`M5&D/
./)"-0#;%/.1i#P.>TH`M;%<+156+*5]&X;%<3!,#
%/)56=/7.S/(g&'M0=K&)+1%>D+1#%21--%B&(&/)+
.K:=K#R%+%f9f+=K&)+1%>D.>E+#%6+%/)=’T9G+1
%>D%cT9G(M5]#"+.8#%G+%/b!+<5!,#+%4M%c
=K&)+1%>D5].>E+5CHQ+^&D/+"+94/=K&);%"+%’:
#J+>?#R%+%f9f+

1.6.4. Bảo vệ so lệch:
K&)59)+%#"+.8;%/3!,#%/)5659)+%/cA%c/"#L
HI./)#h%A/.B!+@A&^.>E+=K&)q%$%dr~o
Hình 1-5
—+%7.89(:&/)+=$%#%>?0HI./)i%A/.B!+@A&^
.>E+=K&)9A=’%A!0#N+9(n

Ad
w
=d
H.1
Ad
r
=d
wv
7!3!,#%/)56+*i=P(/&^=K&)0&RHQ%>;%/\
:4+%#4/./2:[0&'M#%$HI./)i%A/.B!+@A&^.>E+=K&)5]&X
=’%A!n

At
w
=t0
H.1
At
£
=t
wv
7!3!,#%/)56+*#&^=K&) &RHQ#4/./2:[
•
0+"+

HI./)
A|
&(
=|
i%A/.B!+@A&^.>E+=K&);%<+I=’%A!
cA0H&'Mn

A|
©
=|

A|
r
=|
©v
Z(0!MP#\+59)+%+%-%F-#A-%`=/)#56+*#
&^.>E+=K&)&D/56+*3!,#%/)=P(/&^(Mg&'M0=K
&)59)+%.>E++%f9f+
—+%7.89(:&/)+=$%#%>?05659)+%+@AHI./)i%A/.B!
+@A&^.>E+=K&)9(=’;%<0HI./);%i/.8+@A=K&)5
t~