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Mở đầu %&&'()*+),-. /0,%12()*+345#6)' 778370 9:;1<=4<>7#1 35?.,*@')()4-AB%:7 CD)#E=0FGHIH E-#0J',8=:,7)8) *0 95<*KL&)%E K.,0KMN*,%')51: 3')317K:*#) *1,0 O)3K.,1*5KPKIQ#) G095.*KMN*,;1HGN*& ')NB5KI&*G>*#3 KI()*;7&')#EN%:5.,3 =1830R*## *8()*.S7)#*=%T 6()*U5N*0 1.2. Các yêu cầu đối với hệ thống chống sét đánh thẳng V7)8):N*%G 18W+*N*0 9: !#$*KL&)%E>I:<K., !#$*KL K.,0 9: !#$32*>K33541 )7#G)N*0#G)3XGN* Y<XG*KI#),G YZ[*G:>4#3GU)5 1N*HG0 \.),)G.<%)&K.,,>;', #KL&)%E5,;,7)8)#@*5 &)%E5GN*B,%:]0 KK.,KPKIN%:5U1# 3KI,()*0 FR),^$_`O9`#] $9`<9+a\*OR&   !"!#$ 9:K.,*YK+Y-)KN*<K.,4 *<K.,=0 1.3. Phạm vi bảo vệ của cột thu sét và dây chống sét 1.3.1. 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Phạm vi bảo vệ của dây thu sét dN*K.,=5;? h x 1,2h 0,6h h x h 0,2h J., Hnh 1.4. !"#$%&'( FR),^$_`O9`#] $9`<9+a\*OR& [  !"!#$ -)&N*=YE2*) `\ b f; DAe>!      −=    A0nD `\b≤; D c>! A >      −=   A0!D dK+Y-)K<K.,;? C B A α 2 α 1 Hnh 1.5.) !"#$%&'( 35=3:α%Z! ! <%G,# αj ! ! ÷ ] ! 1.4. Mô tả đối tượng bảo vệ ` !#$"!#$>o*,__ `-)& ! `-)K ! `b*!#$*c>b* !#$*g0 `Fo4W;? FR),^$_`O9`#] $9`<9+a\*OR& ] !"!#$ 210 120 5 5 8x17=1366 5 5 15x10=150 4 4.5 5 13 14 8.5 6.5 5 5 21 AT1 AT2 27 13 7 25.5 33.5 7 16 4 4 912 Hình 1.6. Mặt bằng trạm biến áp 220/110 kV 17m 17m 17m 17m 17m17m 17m 17m 17m 17m17m 17m 17m 17m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m 17m 11m 11m Bể n ớc Trạm bơm cứu hỏa Nhà điều khiển Nhà QLVH TN2 TN1 Bể dầu sự cố AT1 AT2 8m FR),^$_`O9`#] $9`<9+a\*OR& e !"!#$ 1.5. Tớnh toỏn, la chn cỏc phng ỏn bo v chng sột ỏnh thng cho trm bin ỏp 1.5.1. Phng ỏn 1 Hình 1.7: Sơ đồ bố trí các cột thu lôi của ph ơng án 1 4 4.5 AT1 AT2 4 4 11m 17m 17m 17m 17m17m 17m 11m 17m 11m 17m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m 11m Bể n ớc Trạm bơm cứu hỏa Nhà điều khiển Nhà QLVH TN2 TN1 Bể dầu sự cố AT1 AT2 8m 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 8m 8m 8m 8m 8m FR),^$_`O9`#] $9`<9+a\*OR& g  !"!#$ *+,+*+*-&. `d* !#$]& `d*!#$ & &)%E 7b*g 7b* 7b*c d* !#$ &> >Z>[>]>>  &e>g>c>n>! d*!#$ & > Z> [> ]> e> g &e>g>c>n> !>  *+,+*+./* 0.1#2"'( 95=&*KMN*&)*b1=< #<I*()*.&J09&*KMh -)#  c 3   ≥ 40.56 9<#<I;@'Ap pgpeD>A pZpcpgD>  AZp[pnpcD>A[p]p!pnD% Z[ g Zc>!A D3  = + = 9&*KM5)N*&,% Zc>! [>g]A D c c  3   = = = 9<#<I;@'Aepgp pD>AgpcpZp D> Acpnp[pZD>Anp!p]p[D% Z[ Z[ [c>!cA D3  = + = 9&*KM5)N*&,% Zc>! [>g]A D c c  3   = = = *3#()%)*) Bảng 1.1.7#2"'( FR),^$_`O9`#] $9`<9+a\*OR& c  !"!#$ 40.**56 9<#<I;@'Aepgp p ZD>Agpcp [p ZD>Acpnp ]p [D>Anp !p ep ]D>A !p p gp eD% Z! Z!>] [ >gcA D3  = + = 9&*KM5)N*&,% [ >gc ]>Z]A D c c  3   = = = *3#()%)*) Bảng 1.2.7#2"'( qDr@*! !#$ s<#<I*ApgpcD>Apcp D> A pnpcD>A pnp !D>A p !pZD>AZp p !D>AZp p[D>A[p p]D>*G, $:%i*)p*>>%pF>tJ%8%=%K># <#<I*0 uKME2EF>*3  A DA DA D8        = − − −  [  8 9 = F),* A D  3  8 = FR),^$_`O9`#] $9`<9+a\*OR& n  !"!#$ s*ApgpcD3 Z! ZZ>e [>Z [Z>n]A D      + + + + = = = [Z>n]0A[Z>n] Z!DA[Z>n] ZZ>eDA[Z>n] [>ZD Z]Z> A D8  = − − − = Z!0ZZ>e0 [>Z Z[>ecA D 0Z]Z>  3  8 = = = 9&*KM5)N*&,%  Z[>ec [>Z[A D c c  3   = = = *3#()%)*) Bảng 1.3. 7#2"'( R',*35%G,&*KM)&%e>]AD 9&*&)%E*!#$%  e>] g>]A D       = + = + = 9&*&)%E* !#$% g e>] Z>]A D       = + = + = 0 !":; qDdN*&*!#$3&*g>] a#H&*c  c 0g>] >eg Z Z    = < = = 7 c c >]0g>]0A D > ]A D !>c0g>]   = − = a#H&*   0g>] >eg Z Z    = < = = 7   >]0g>]0A D ]>e ]A D !>c0g>]   = − = qDdN*&* !#$3&* Z>] a#H&*   0 Z>] ]>eg Z Z    = < = = 7 l   >]0 Z>]0A D [>e ]A D !>c0 Z>]   = − = a#H&*g      g 0 Z>] ]>eg Z Z    = > = =  7  l g g !>g]0 Z>]0A D [>cg]A D Z>]   = − = FR),^$_`O9`#] $9`<9+a\*OR& ! [...]... Hình 1.10 Sơ đồ phạm vi bảo vệ của ph ơng Vin in -Trng i hc Bỏch Khoa H Ni 22 Chng 2: Tớnh toỏn ni t cho trm bin ỏp 220/110kV CHNG 2 TNH TON NI T CHO TRM BIN P 220/110kV 2.1 Yờu cu ni t cho trm bin ỏp Nhim vu cua ni t l tn dong in xung t m bo cho in ỏp trờn vt c ni t cú tr s bộ H thng ni t l mt b phn quan trng trong vic bo v quỏ in ỏp, tuy theo nhim vu v hiu qu m h thng ni t c chia lm 3 loi +) Nụi t... xung quanh trm bng cỏc thanh dt Mch vong cỏch múng tng bao quanh trm mi chiu 1m Sv: Nguyn Vit Anh -HT 1 -k52 Vin in -Trng i hc Bỏch Khoa H Ni 26 Chng 2: Tớnh toỏn ni t cho trm bin ỏp 220/110kV Hinh 2.1 Mt bng trm bin ap 220/110 kV L8=76m 4 L1=152,25m Bể dầu sự cố AT1 4 L6=42m 4 L7=55,75m AT2 L5=168m Sv: Nguyn Vit Anh -HT 1 -k52 Vin in -Trng i hc Bỏch Khoa H Ni 27 Chng 2: Tớnh toỏn ni t cho trm bin ỏp 220/110kV. .. o khụng i Vy in tr cua mch vong l: R = mv K R mv( set ) mv( an toan) 1, 2.1,13 = = 0,85 K 1, 6 mv(an toan) in tr cua cc l: Sv: Nguyn Vit Anh -HT 1 -k52 Vin in -Trng i hc Bỏch Khoa H Ni 33 Chng 2: Tớnh toỏn ni t cho trm bin ỏp 220/110kV R = coc K R coc ( set ) coc (an toan) 1,15.57, 68 = = 47,38 K 1, 4 coc(an toan) in tr ni t nhõn to tớnh cho ni t chng sột l: R R coc mv R = nt ( set ) R + n.R coc mv... +) Nụi t an ton Cú nhim vu m bo an ton cho ngi khi cỏch in b h hng Thc hin ni t an ton bng cỏch ni t cỏc b phn kim loi khụng mang in nh v mỏy in, thung du mỏy bin ỏp, cỏc giỏ kim loi Khi cỏch in b h hng thi trờn cỏc b phn kim loi se cú mt in th nhng do ni t nờn in th ny nh khụng gõy nguy him cho ngi +) Nụi t chụng set Cú tỏc dung lm tn dong in sột vo trong t khi cú sột ỏnh vo ct thu lụi hay dõy chng... hoc dng tng quỏt: xk = f ( I , ) (2.9) b) Tớnh toan nụi t phõn bụ di khụng xet n qua trỡnh phong in trong t S ụ ng tr cua ni t c th hin nh sau: Sv: Nguyn Vit Anh -HT 1 -k52 Vin in -Trng i hc Bỏch Khoa H Ni 31 Chng 2: Tớnh toỏn ni t cho trm bin ỏp 220/110kV L G R L G C R L G C R L G C R C Hinh 2.5 S ng tr ca h thụng nụi t Trong mi trng hp u cú th b qua in tr tỏc dung R vi nú bộ so vi tr s in tr tn,... Tớnh toan nụi t phõn bụ di khi co xet qua trỡnh phong in trong t Vic gim in ỏp v mt dong in cỏc phn xa cua in cc lm cho quỏ trinh phúng in trong t cỏc ni ny cú yu hn so vi u vo cua ni t Do ú in dn cua ni t (trong s ụ ng tr) khụng nhng ch phu thuc vo I, m con phu thuc vo to Tuy nhiờn vic tớnh toỏn tng tr se rt phc tp vi vy ta cú th b qua trong phm vi ụ ỏn ny d) Tớnh toan li tr sụ in tr nhõn to... gii hn cho phộp Sv: Nguyn Vit Anh -HT 1 -k52 Vin in -Trng i hc Bỏch Khoa H Ni 23 Chng 2: Tớnh toỏn ni t cho trm bin ỏp 220/110kV - i vi cỏc thit b in cú im trung tớnh trc tip ni t yờu cu in tr ni t phi tho man: R 0,5 - i vi cỏc thit b cú im trung tớnh cỏch in thi: R 250 I - i vi h thng cú im trung tớnh cỏch in vi t v ch cú mt h thng ni t dung chung cho c thit b cao ỏp v h ỏp thi: R 125 I - Khi dung... Tớnh phõn bụ in ap v tng tr xung kớch ca h thụng nụi t T s ụ thay th ta cú phng trinh vi phõn Sv: Nguyn Vit Anh -HT 1 -k52 Vin in -Trng i hc Bỏch Khoa H Ni 34 Chng 2: Tớnh toỏn ni t cho trm bin ỏp 220/110kV U I = L x t i = G.U x Trong thit k tớnh toỏn ta chn dng súng cua dong in sột l dng súng xiờn gúc cú biờn khụng i Phng trinh súng cú dng sau: khi t < at ds I = S I = a. khi t > ds ds... chung cho cỏc nhim vu Song h thng ni t chung phi m bo yờu cu cua cỏc thit b cú dong ngn mch ln do vy in tr ni t phi nh Khi in tr ni t nh thi cú th tn dong in vi mt ln, tỏc dung cua ni t an ton hn Nhng t c in tr ni t nh thi rt tn kộm do vy trong tớnh toỏn ta phi thit k sao cho hp lớ c hai yu t m bo k thut v kinh t Mt s yờu cu v k thut cua in tr ni t: - Tr s in tr ni t cua ni t an ton c chn sao cho cỏc... -Trng i hc Bỏch Khoa H Ni 35 Chng 2: Tớnh toỏn ni t cho trm bin ỏp 220/110kV 1 1 1 1 2 = 2 + 2 + + 2 + = = 1,645 k2 1 2 6 k k =1 1 k k =1 2 e ds TK = ds T1 ds T2 (2 20) ds TK e e e + 2 + + 2 + 2 1 2 k (2 21) Trong day s ny ta ch xột n s hng cha e-4, t s e-5 tr i cú giỏ tr rt nh so vi cỏc s hng trc nờn ta cú th b qua, ta tớnh n k sao cho: ds 4 Tk 22) (2 ds ds 4.T T = 4 hay k 2 1 . đầu %&&'()*+),-. /0,%12()*+345#6)' 778370 9:;1<=4<>7#1 35?.,*@')()4-AB%:7 CD)#E=0FGHIH E-#0J',8=:,7)8) *0 95<*KL&)%E K.,0KMN*,%')51: 3')317K:*#) *1,0 O)3K.,1*5KPKIQ#) G095.*KMN*,;1HGN*& ')NB5KI&*G>*#3 KI()*;7&')#EN%:5.,3 =1830R*## *8()*.S7)#*=%T 6()*U5N*0 1.2 đầu %&&'()*+),-. /0,%12()*+345#6)' 778370 9:;1<=4<>7#1 35?.,*@')()4-AB%:7 CD)#E=0FGHIH E-#0J',8=:,7)8) *0 95<*KL&)%E K.,0KMN*,%')51: 3')317K:*#) *1,0 O)3K.,1*5KPKIQ#) G095.*KMN*,;1HGN*& ')NB5KI&*G>*#3 KI()*;7&')#EN%:5.,3 =1830R*## *8()*.S7)#*=%T 6()*U5N*0 1.2 đầu %&&'()*+),-. /0,%12()*+345#6)' 778370 9:;1<=4<>7#1 35?.,*@')()4-AB%:7 CD)#E=0FGHIH E-#0J',8=:,7)8) *0 95<*KL&)%E K.,0KMN*,%')51: 3')317K:*#) *1,0 O)3K.,1*5KPKIQ#) G095.*KMN*,;1HGN*& ')NB5KI&*G>*#3 KI()*;7&')#EN%:5.,3 =1830R*## *8()*.S7)#*=%T 6()*U5N*0 1.2.