BÀI GIẢNG KHÍ CỤ ĐIỆN · PDF fileRƠ LE ĐIỀU KHIỂN VÀ BẢO...
Transcript of BÀI GIẢNG KHÍ CỤ ĐIỆN · PDF fileRƠ LE ĐIỀU KHIỂN VÀ BẢO...
BI GING KH C IN
CHNG 6 :
R LE IU KHIN V BO V
B CNG THNG
TRNG I HC CNG NGHIP TP.HCM
KHOA IN
R-le l loi kh c in dng t ng ng ct mch
iu khin , bo v v iu khin s lm vic ca mch
in.
C nhiu cch phn loi r le:
Phn loi theo nguyn l lm vic c:
R-le in t.
R-le in ng.
R-le t in.
R-le cm ng.
R-le nhit..
KHI QUT V PHN LOI
Phn loi theo vai tr v i lng tc ng ca r-le c:
R-le trung gian.
R-le thi gian.
R-le nhit.
R-le tc .
R-le dng in.
R-le in p.
R-le cng sut.
R-le tng tr.
R-le tn s
KHI QUT V PHN LOI
Phn loi theo dng in c:
R-le dng in mt chiu.
R-le dng in xoay chiu.
Phn loi theo gi tr v chiu ca i lng i vo r-
le:
R-le cc i.
R-le cc tiu.
R-le sai lch.
R-le hng
KHI QUT V PHN LOI
R le trung gian:
R-le trung gian l kh c in dng trong cc s bo v
cc h thng in, h thng iu khin t ng, lm vic
theo c cu kiu in t, ng vai tr iu khin trung gian
gia cc thit b iu khin (contactor, r-le thi gian).
R-le trung gian c cu to gm: mch t ca nam chm
in, h thng tip im chu dng in nh ( 5A), v bo
v v cc chn ra tip im.
MT S LOI R LE THNG DNG
Nguyn l hot ng
Khi cp in p bng gi tr in p nh mc vo hai u
cun dy r-le trung gian, lc in t ht mch t kn li,
h thng tip im chuyn i trng thi v duy tr trng
thi ny (tip im thng ng h ra,thng h ng li).
Khi ngng cp ngun, mch t h, h thng tip im tr
v trng thi ban u.
R LE TRUNG GIAN
im khc bit gia contactor v r-le trung gian ?
Trong r-le trung gian ch c tip im c kh nng chu
dng in nh (tip im thng ng v tip im thng
m), s dng cho mch iu khin v khng c h thng dp
h quang.
K hiu SPDT:
SINGLE POLE DOUBLE THROW, r-le mang k hiu
ny c mt cp tip im, gm tip im thng ng v
thng h, cp tip im ny c mt u chung.
3 5
4 1
2
SPDT
K hiu SPST:
SINGLE POLE SINGLE THROW, r-le mang k hiu
ny gm c mt tip im thng h.
4 3
1
2
SPST
K hiu DPDT:
DOUBLE POLE DOUBLE THROW, r-le mang k
hiu ny gm c hai cp tip im . Mi cp tip im
gm tip im thng ng v thng h, cp tip im
ny c mt u chung.
3 5
1
2
DPDT
6 8
4
7
K hiu DPST:
DOUBLE POLE SINGLE THROW, r-le mang k hiu
ny gm c hai tip im thng h.
4
3
1
2
DPST
6
5
Ngoi ra, cc r-le khi c lp ghp trong t iu khin
thng c lp trn cc chn ra. Ty theo s lng
chn ra ta c cc kiu khc nhau: 8 chn, 11 chn,
14 chn
L kh c in dng trong lnh vc in iu khin, in t
ng, vi vai tr iu khin trung gian gia cc thit b iu
khin theo thi gian nh trc.
Cu to gm: mch t ca nam chm in, b nh thi
gian lm bng linh kin in t, h thng tip im chu
dng in nh ( 5A), v bo v v cc chn ra tip im.
Ty theo yu cu s dng c hai loi r-le: r-le thi gian
ON DELAY, r-le thi gian OFF DELAY.
R LE THI GIAN
K hiu: TR TR
in p t vo hai u cun dy r-le thi gian c ghi trn nhn,
: 110V, 220V
H thng tip im:
TR TR
TR
TR
TR
TR
TR
TR
Thng ng :
Thng h :
Tip im tc ng c tnh thi gian:
Tip im thng m ,ng chm, m
nhanh:
Tip im thng ng ,m chm , ng
nhanh:
R LE THI GIAN ONDELAY
Khi cp ngun vo cun dy ca r-le thi gian ON
DELAY, cc tip im tc ng khng tnh thi gian
chuyn i trng thi tc thi, cc tip im tc ng c
tnh thi gian khng i. Sau khong thi gian nh
trc, cc tip im tc ng c tnh thi gian s chuyn
trng thi v duy tr trng thi ny.
Khi ngng cp ngun vo cun dy, tt c cc tip im
tc thi tr v trng thi ban u.
R LE THI GIAN ONDELAY
Sau y l s chn ca r-le thi gian ON DELAY:
2
1
3 6
4 5
7
8
source
Hnh dng c th ca r-le thi gian ON DELAY
c ph bin:
Khi cp ngun vo cun dy ca r-le thi gian OFF
DELAY, cc tip im tc ng tc thi v duy tr trng
thi ny.
Khi ngng cp ngun vo cun dy, tt c cc tip im
tc ng khng tnh thi gian tr v trng thi ban u.
Tip sau mt khong thi gian nh trc, cc tip
im tc ng c tnh thi gian s chuyn v trng thi
ban u.
R LE THI GIAN OFF DELAY
R le thi gian OFF DELAY:
K hiu: TR TR
in p t vo hai u cun dy r-le thi gian : 110V, 220V
TR TR
TR
TR
TR
TR
TR
TR
Thng ng :
Thng h :
Tip im tc ng c tnh thi gian:
Tip im thng m ,ng nhanh, m
chm:
Tip im thng ng ,m nhanh, ng
chm:
Sau y l s chn ca r-le thi gian OFF DELAY:
2
1
3 6
4 5
7
8
source
Khi nim :
L kh c in bo v ng c v mch in khi s c qu
ti. Thng dng km vi cng tc t.
Dng in p xoay chiu n 500v, tn s 50Hz. Mt s
kt cu mi ca rle nhit c dng nh mc n 150A,c
th dng li in 1 chiu, in p n 440V
R-le nhit khng tc ng tc thi theo tr s dng in
v n c qun tnh nhit ln, phi c thi gian pht nng,
do n lm vic c thi gian t vi giy n vi pht.
R LE NHIT (ORL)
R LE NHIT (ORL)
Nguyn l hot ng:
Da trn tc dng nhit ca dng in lm gin n phin
kim loi kp. Phin kim loi kp gm hai l kim loi c h
s gin n khc nhau ghp cht vi nhau thnh mt phin
bng phng php cn nng hoc hn. Khi c dng in
qu ti i qua, phin lng kim c t nng, un cong v
pha kim loi c h s gin n b, y cn gt lm l xo co
li v chuyn i h thng tip im ph.
r-le nhit lm vic tr li, phi i phin kim loi ngui
v ko cn reset ca r-le nhit.
Phin lng kim nhit
Tip im chnh
Tip im ph:
K hiu
OL
OL
OL
OL
hoc
Phn loi R le nhit:
Theo kt cu: r-le nhit chia thnh hai loi: kiu h v
kiu kn
Theo yu cu s dng: loi mt cc v hai cc
Theo phng thc t nng:
t nng trc tip: dng in i qua trc tip tm kim
loi kp. Loi ny c cu to n gin, nhng khi thay
i dng in nh mc phi thay i tm kim loi kp,
loi ny khng tin dng t nng
t nng gin tip: dng in i qua phn t t nng
c lp, nhit lng to ra gin tip lm tm kim loi kp
cong ln.
u im: mun thay i dng in nh mc ta ch cn
thay i phn t t nng.
Khuyt im : khi c qu ti ln, phn t t nng c th
t n nhit kh cao nhng v khng kh truyn nhit
km, nn tm kim loi cha kp tc ng m phn t t
nng b chy t.
t nng hn hp: loi ny tng i tt v va t trc
tip va t gin tip. N c tnh n nh nhit tng i
cao v c th lm vic bi s qu ti ln.
Chn la R le nhit:
c tnh c bn ca r-le nhit l quan h gia dng in ph ti
chy qua v thi gian tc ng ca n. m bo tui th lu di
ca thit b theo ng s liu k thut ca nh sn xut, cc i
tng bo v cng cn c tnh thi gian - dng in.
La chn ng r-le nhit l sao cho ng c tnh A-s ca r-le
gn st ng c tnh A-s ca i tng cn bo v. Nu chn thp
qu s khng tn dng c cng sut ca ng c in, chn cao
qu s lm gim tui th ca thit b cn bo v.
Cch chn ph hp l chn dng in nh mc ca r-le nhit bng
dng in nh mc ca ng c in cn bo v, r-le s tc ng
gi tr (1,21,3) Im.
R le nhit ca hng Merlin gerin
Chnh dng ca Rle
nhit
Ch Auto/ Hand
(A/H)
NO (Normal Open) : tip im ph thng h.
NC (Normal Close) : tip im ph thng ng
DC
CB
L1
L2L3
D
CC
K K
RN
M
K
RN NK
NT
TT
KN
T
MN
KN
KN
KT
DC
CB
L1
L2L3
D
CC
K K
RN
M
KK
RN NK
Rth
K K
K
K
Rth
Rth Y
Y
Y
31
CU HI
1) Cng dng ca rle thi gian, rle trung gian, rle nhit
2) Nguyn l cu to ca rle thi gian, rle trung gian, rle nhit
3) iu kin la chn rle nhit bo v ng c
4) Ti sao rle nhit lun i km vi Contactor? Nu khng c
Contactor rle nhit lm vic c khng? Gii thch ?
5) Trong mt s iu kin mi trng thp, rle nhit khng thc hin
c, nu gii php bo v qu ti ng c trong trng hp ny ?
6) Trong rle nhit 3 pha, c hai l lng kim nhit trn hai pha, gii
thch v sao ch s dng hai l lng kim m khng s dng ba l.
7) Nt reset trn rle nhit c 2 ch : A v H. hai ch ny c
ngha nh th no? khi no s dng ch A, khi no s dng ch
H, gii thch ?
8) Phn bit Rle thi gian On Delay vi Rle thi gian Off Delay
9) Phn bit Contactor in t v rle trung gian