Đồ án môn học lưới điện

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n mn hc li inLI NI U Nc ta ang trong qu trnh cng nghip ho, hin i ho xy dng CNXH. c bit qu trnh m ca ngy cang su rng, ra nhp WTO cng lm kinh t nc ta pht trin ngy cng mnh m hn, rt nhiu cc nh my, khu cng nghip mi c xy dng. Nng lng ni chung v in nng ni ring lun phi m bo i trc mt bc nhm chun b cho xy dng cc nh my sn xut cng nghip. iu i hi chng ta phi xy dng cc nh my in, mng li in sn xut, truyn ti in nng cho cc ph ti ny. Vic thit k cc mng li in khu vc cung cp cho cc nh my cng nghip l mt l mt nhim v rt quan trng i vi cc k s h thng in. n mn hc thit k mng li in khu vc gip chng ta vn dng nhng kin thc hc vo thc t cng vic, n gip chng ta c nhng k nng c bn phc v cho lm n cng nh thc t cng vic sau ny. Qa trnh lm n s khng th trnh khi khim khuyt do kin thc bn thn cn hn ch, v vy em knh mong cc thy c ch bo gip tn tnh bn n hon thin hn. Em xin chn thnh cm n!

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n mn hc li inCHNG I: PHN TCH NGUN V PH TI 1.1 S mt bng T l:1 n v =10 km15 13 11 9 7 5 3 1 0 2 4 6 8 10 12 14 16

2 6 N 1

3 4 5

Ngun cung cp cho cc ph ti l nh my in hoc trm bin p khu vc c cng sut m bo cung cp cho cc ph ti theo yu cu. 1.2 Bng s liu ph ti Cc s liu Ph ti cc i(MW) H s cng sut cos Mc m bo cung cp in Yu cu iu chnh in p in p danh nh li in th cp(kV) 1 38 1 Cc h tiu th 2 3 4 5 18 38 29 18 0,9 1 1 1 1 Khc thng 10 6 29 1

CHNG II. CN BNG CNG SUT TC DNG V PHN KHNG TRONG H THNG2

n mn hc li in2.1 Bng s liu ph ti Cc s liu Ph ti cc i(MW) H s cng sut cos Mc m bo cung cp in Yu cu iu chnh in p in p danh nh li in th cp(kV) 1 38 1 Cc h tiu th 2 3 4 5 18 38 29 18 0,90 1 1 1 1 Khc thng 10 6 29 1

2.2 Cn bng cng sut tc dng Mt c im quan trng ca h thng in l truyn ti tc thi in nng t ngun in n cc h tiu th m khng th tch lu c. Tnh cht ny th hin s ng b trong qu trnh sn xut in nng. Ti mi thi im trong ch xc lp ca h thng, cc nh my pht in trong h thng phi pht cng sut in ng bng cng sut tiu th ca cc ph ti trong h thng ng thi cng thm cc tn tht pht sinh trong qu trnh truyn ti. Ngoi ra m bo h thng vn hnh n nh trong cc iu kin khc nhau, h thng pht in ca nh my phi c d tr cng sut tc dng nht nh. Mc d tr cng sut tu thuc vo yu cu ca h thng v mc pht trin sau ny. PF =PYC = mPpt +P +Ptd+Pdt (1.21) Ta c phng trnh cn bng cng sut tc dng trong h thng: Trong : PF:Tng cng sut tc dng pht ra t ngun pht. Ppt:Tng cng sut tc dng ca cc ph ti trong ch ph ti P :Tng tn tht cng sut tc dng trong mng in, khi tnh s b c th ly P = 5%.Pmax Ptd :Tng cng sut t dng ca nh my in Pdt :Tng cng sut d tr trong mng in,khi cn bng s b c th ly : Pdt = 10%.Pmax m : h s ng thi xut hin cc ph ti cc i3

n mn hc li inMt cch gn ng ta c th thay bng cng thc: PF = Ppt + 15%Ppt. (1.2.2) Theo bng s liu v ph ti cho trn ta c : PF =Pyc = 1,15.(38+28+38+29+18+29) = 178,5 (MW) Vic cn bng cng sut tc dng gip cho tn s ca li in lun c gi n nh.2.3 Cn bng cng sut phn khng trong h thng.

Cn bng cng sut phn khng c quan h ti in p.H thng khng cn bng cng sut phn khng s dn ti thay i in p trong h thng in. Nu cng sut phn khng pht ra ln hn cng sut phn khng tiu th th in p trong h thng s tng, ngc li nu cng sut phn khng pht ra nh hn cng sut phn khng tiu th th s dn ti s sut p. V vy m bo cht lng ca h thng in ta cn phi cn bng cng sut phn khng trong h thng. Phng trnh cn bng cng sut phn khng trong h thng: QF = Qyc =mQpt +Qb +QL -Qc +Qtd +Qdt (1.3.1) Trong : QF :Tng cng sut phn khng do ngun in pht ra Qyc: Tng cng sut yu cu ca h thng Qpt :Tng cng sut phn khng ca cc ph ti ch cc i QL :Tng cng sut phn khng trong cm khng ca cc ng dy trong mng in. Qc : tng cng sut phn khng do in dung ca cc ng dy sinh ra,khi tnh s b ly : Qc = QL Qb : tng tn tht cng sut phn khng trong cc trm bin p ,khi tnh s b c th ly Qb = 15%Qmax Qtd: tng cng sut phn khng t dng trong nh my in. Qdt : Tng cng sut phn khng d tr trong h thng. m :h s ng thi Trong tnh ton s b ta c th tnh tng cng sut phn khng yu cu trong h thng bng cng thc sau y:4

n mn hc li inQyc = Qpt + 15%Qpt (1.3.2) Cng sut phn khng ca cc ph ti c tnh theo cng thc sau Qpt =Ppt. tg (1.3.3) T cos= 0,9 ta suy ra tg= 0,484 Ta c bng s liu sau: Cc h ph ti 1 2 3 4 Q(MVAr) 18,404 8,718 18,404 14,045 Bng 2.1:cng sut phn khng ca cc ph ti p dng cng thc 1.3.2 ta c Qyc= 1,15.(18,404+8,718+18,404+14,045+8,718+14,045)= = 94,685 MVAr T cos= 0,85 ta suy ra tg= 0,62 Ta li c : QF = PF .tg = 178,5 .0,62 = 110,624 MVAr > Qyc = 94,685 MVAr Nh vy cng sut phn khng pht ra ln cng sut phn khng tiu th ca h thng do vy ta khng phi b cng sut phn khng. KT LUN Sau khi tnh ton ta c s liu ca cc ph ti c cho trong bng 1.3.2 Cc h tiu th Pmax(MW) Qmax(MVAr) Smax(MVA) cos 1 38 18,404 42,222 0,9 2 18 8,718 20,000 0,9 3 38 18,404 42,222 0,9 4 29 14,045 32,222 0,9 5 18 8,718 20,000 0,9 6 29 14,045 32,222 0,9 5 8,718 6 14,045

Bng 2.2 S liu tnh ton ca cc h ph ti

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n mn hc li inCHNG III D KIN CC PHNG N NI DY CA MNG IN V SO SNH CC CH TIU K THUT 3.1 M u Cc ch tiu kinh t k thut ph thuc rt nhiu vo s ni dy ca n.V vy ta phi c cc phng n ni dy khc nhau trong mng li in t so snh tm ra phng n ti u nht:va bo m cc ch tiu k thut ng thi bo m chi ph nh nht, tin cy cn thit, thun li cho vn hnh, sa cha, ng thi bo m kh nng pht trin tng lai tip nhn thm ph ti mi. T s mt bng ngun in v cc ph ti cho ta c th a ra cc phng n ni dy cho mng li in trn. Sau y l 5 phng n v tnh ton nh gi cc ch tiu k thut ca cc phng n ny. 3.2 D kin cc phng n 3.2.1 Phng n I15 13 11 9 7 5 3 1 0 2 4 6 8 10 12 14 16

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Hnh 3.1:S ni dy phng n I

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n mn hc li in3.2.2 Phng n II15 13 11 9 7 5 3 1 0 2 4 6 8 10 12 14 16

2 6 N 1

3 4 5

Hnh 3.2 : S ni dy phng n II 3.2.3 Phng n III15 13 11 9 7 5 3 1 0 2 4 6 8 10 12 14 16

2 6 N 1

3 4 5

Hnh 3.3 : S ni dy phng n III

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n mn hc li in3.2.4 Phng n IV15 13 11 9 7 5 3 1 0 2 4 6 8 10 12 14 16

2 6 N 1

3 4 5

Hnh 3.4 : S ni dy phng n IV 3.2.5 Phng n V15 13 11 9 7 5 3 1 0 2 4 6 8 10 12 14 16

2 6 N 1

3 4 5

Hnh 3.5 : S ni dy phng n V

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n mn hc li in3.3 Phng n ni dy 1 3.3.1 S ni dy15 13 11 9 7 5 3 1 0 2 4 6 8 10 12 14 16

2 6 N 1

3 4 5

Hnh 3.6 : S ni dy phng n I 3.3.2 Tnh in p vn hnh ca mng in in p vn hnh nh hng n cc c trng k thut, cc ch tiu k thut ca mng li in. in p nh mc ca mng li in ph thuc vo nhiu yu t: cng sut ca ph ti, khong cch t ngun n cc ph ti, v tr tng i gia cc ph ti trong mng li in p nh mc c th c chn ng thi vi s cung cp in. in p nh mc s b ca mng in c th xc nh theo gi tr cng sut trn mi on ng dy in. in p nh mc trn ca ng dy c th c tnh theo cng thc kinh nghim sau: Uvhi = 4,34. li + 16. P i (2.1)

Trong : li : khong cch truyn ti trn on ng dy th i (km) Pi :Cng sut truyn ti trn on ng dy th i (MW)9

n mn hc li inDa vo s mt bng ca cc ngun in v cc ph ti ta c in p vn hnh trn cc on ng dy nh sau: in p nh Cng sut Chiu di on ng in p vn mc ca c truyn ti on ng dy hnh, kV mng in, ,MVA dy, km kV N-1 38+ j18,404 56,57 81,31 N-2 18+ j8,718 63,25 61,79 N-3 38+ j18,404 76,16 83,55 N-4 29+ j14,045 125,30 81,20 110 N-5 18+ j8,718 82,46 64,66 N-6 29+ j14,045 111,80 79,62 Bng 3.1: in p vn hnh trn cc on ng dy v in p vn hnh ca c mng in in p vn hnh tnh trong phng n ny c th dng lm in p vn hnh chung cho cc phng n tip theo. 3.3.3 La chn tit din dy dn trn mi on ng dy ca phng n chn. Cc mng in 110 kV ch yu c thc hin bng cc ng dy trn khng, cc dy dn ch yu c dng l dy nhm li thp ( dy AC). i vi cc mng in khu vc tit din dy dn c chn theo mt dng kinh t ca dng in:

Fkt =

I max J kt

(2.2)

Trong : Imax : dng in chy trn ng dy ch ph ti cc i(A); Jkt : mt kinh t ca dng in,A/mm2 Vi dy AC v Tmax = 5500h ta tra bng c c : Jkt = 1,1A/mm2 Dng in chy trn ng dy trong ch ph ti cc i c tnh bng cng thc :

I max =

S max .103 A (2.3) nU dm 3 .

Trong : n: s mch ca ng dy10

n mn hc li inUm : in p nh mc ca mng in , kV Smax : cng sut chy trn ng dy khi ph ti cc i,MVA i vi cc ng dy trn khng , khng xut hin vng quang cc dy nhm li thp cn phi c tit din F 70 mm2 Sau y ta s tnh ton trn tng on ng dy trong phng n 1 on N-1S = 38 + j18,404 MVA 42, 222.103 I max = = 110,80 kA 2. 3.110 110,80 2 Fkt = 1,1 = 110,80 mm

Ta chn theo tit din tiu chun gn nht : AC- 120 Isc = 2.Imax = 2.110,80 = 221,61A < Icp = 380 A (tha mn iu kin pht nng) Tnh ton tng t cho cc on cn li ta c kt qu cho bng 3.2 3.3.4 Tnh tn tht in p trong mng in trong cc trng hp vn hnh bnh thng v ch s c Tn tht in p trn mi on ng dy trong ch d vn hnh bnh thng c tnh bng cng thc

U ibt =Trong

P .R + Q .Xi i i

i

U

2

.100(%)

(2.4)

dm

Uibt : tn tht in p trn on ng dy th i,% Pi, Qi : Cng sut tc dng v cng sut phn khng chy trn on ng dy th i Ri, Xi : in tr v in khng ca on ng dy th i Trong ch s c , i vi mng in ng dy 2 mch tn tht in p trong ch s c (t mt on ng dy ) c tnh theo cng thc : Uisc =2.Uibt i vi on ng dy N-1U N 1bt = 38.8, 212 + 18, 404.12,865 = 4,536 % 1102 11

(2.5)

n mn hc li inTrong trng hp ngng mt mch trn on ng dy N-1 ,ta c: U N-1sc= 2.4,536 = 9,071 % Tnh ton tng t i vi cc on ng dy cn li ta c bng s liu sau: ng dy N-1 N-2 N-3 N-4 N-5 N-6 Ubt% Usc% 4,536 9,071 5,155 10,309 7,604 15,209 3,470 6,941 4,616 9,232 3,222 6,444

Bng 3.3 Tn tht in p trn cc on ng dy trong mng in T cc kt qu trn nhn thy rng ,tn tht in p ln nht trong ch vn hnh bnh thng l: Umax bt = 7,604 % Tn tht in p trong ch s c bng : Umax sc= 15,209 %

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n mn hc li inBng 3.2. Thng s ca cc ng dy trong mng in phng n I

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n mn hc li in

n g dy

Chiu di

S l song song

Smax MVA

Imax (A)

Ftt

Ftc

Isc (A)

Icp (A)

Ro /k m

Xo /k m 0,42 3 0,44 0,42 3 0,42 9 0,44 0,42 9

Bo /km 2,6 9 2,5 8 2,6 9 2,6 5 2,5 8 2,6 5

R ()

X ()

B/2

N-1 N-2 N-3 N-4 N-5 N-6

60,83 102,96 101,98 53,85 92,20 50,00