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TRNG I HC IN LC

Li m u*******Nng lng in l ngun nng lng quan trng khng th thiu trong h thng nng lng chung m ngy nay chng ta dang s dng. in dng trong hu ht cc lnh vc: sinh hot, sn xut, du lch, dch vt nc ta ang trn pht trin, nhu cu v in ngy cng tng. Qu trnh cng nghip ha, hin i ha ang din ra ht sc mnh m, trn khp c nc cc khu dn c, khu cng nghip mi mc ln ngy cng nhiu. iu ny i hi xy dng thm cc mng li in mi truyn ti in nng. Thit k cc mng v h thng in l mt nhim v quan trng ca cc k s ni chung v c bit l cc k s h thng in.Xut pht t iu , bn cnh nhng kin thc c ging dy t nh trng, mi sinh vin h thng in u c giao n mn hc v thit k in cho mng in khu vc. Qu trnh hon thnh n gip sinh vin hiu su hn v mn hc, hnh dung ra mt phn thc t, to tin phc v cho cng vic sau ny. Em xin chn thnh cm n thy Phm Vn Ha, cng ton th cc thy c trong khoa H Thng in trng i hc in lc tn tnh hng dn em hon thnh bn n ny. H Ni, ngy 24 thng 5 nm 2011.

SINH VIN

Bi Tun AnhTRNG I HC IN LCKHOA H THNG IN

THIT K MN HC LI IN

H tn sinh vin: BI TUN ANH Lp : 5H41.S mt bng v tr cc ngun in v cc ph ti:

(1)I(2)

II

(3)IV

III(4)

V(5)VI(6)

2.Ngun : Cng sut v cng ln3.Ph ti:Ph ti I II III IV V VI

Pmax;MW 20 25 28 32 35 40

Pmin 70%Pmax

Cos( 0.85

Loi h II II I II II I

Gia 1 kWh in nng tn tht : 700 /kWhGia 1 kVAr thit bi bu : 150.103 /kVAr;

H s ng thi m =1; Thi gian s dung cng sut cc ai Tmax= 5000 h; JKT = 1,1 A/mm2. in ap trn thanh cai cua ngun in khi phu tai cc tiu UA = 1,05 Um, khi ph ti cc i UA = 1,1 Um, khi s c nng n UA = 1,1 Um.4.Ni dung tnh ton: 1 - Tinh toan cn bng cng sut, xy dng phng an.

2 - Tinh toan kinh t ky thut, chon phng an ti u.

3 - Chon may bin ap va s ni in chinh.

4 - Tinh toan ch xac lp li in.

5 - Tinh toan la chon u phn ap.

6 - Tinh toan cac chi tiu kinh t ky thut.

CHNG I

TINH TOAN CN BNG CNG SUT VA XY DNG PHNG AN1.1.Phn tich ngun va phu tai.S liu phu tai123456

Pmax (MW)202528323540

Qmax (MVAR)12.415.517.3619.8421.724.8

Pmin (MW)1417.519.622.424.528

Qmin (MVAR)8.6810.8512.15213.88815.1917.36

Cos(0,850,850,850,850,850,85

Loai phu taiIIIII IIIII

1.2. Tinh toan cn bng cng sut.

1.2.1. Cn bng cng sut tac dung.Tng cng sut tac dung do ngun sinh ra phai bng tng cng sut tac dung do cac phu tai tiu thu va tn tht cng sut tac dung trn li (khu vc).

Trong o: Ptram: Tng cng sut phat cua tram in. m : H s ng thi. Trong tinh toan thit k ly m = 1 Pptj : Tng tn tht trn ng dy va may bin ap trong mang in. m.Pptj= Ppt1 + Ppt2 + Ppt3 + Ppt4 + Ppt5 + Ppt6

= 20+25+28+32+35+40= 180 (MW) Pmd : Tng tn tht trn ng dy va may bin ap trong mang in.

Khi tinh toan s b ta ly theo phn trm cua tng cng sut phu tai cc ai.

Pmd= 5%*m*ptj= 0.05*180= 9 (MW)Vy Ptram= 1*180 + 9= 189 (MW)1.2.2. Cn bng cng sut phan khang va bu cng sut cng bc.

S cn bng cng sut phan khang c th hin bng biu thc sau:

Qb + Qtram = m. Qpt + QB

Trong o :

Qtram : Tng cng sut phan khang do tram in phat ra.

Qtram = Ptram*tg(tram = Ptram*tg(arccos 0.85)

Qtram = 189*0.62 = 117.18 (MVAr)

Qpt : Tng cng sut phan khang cua phu tai. Qpt = Pptj.tg(ptj = 180*0.62= 111.6 (MVAr)QB : Tng tn tht cng sut phan khang trong may bin ap. c tinh theo phn trm cua cng sut phu tai. QB = 15%*m*Qpt = 0,15*1*111.6 = 16.74(MVAr).Qb : Tng cng sut phan khang bu s b.

Qb = (m*Qpt + QB) - Qtram = 1*111.6 + 16.74 117.18 = 11.16 (MVAr). Ta d kin bu s b da trn nguyn tc la bu u tin cho cac h xa, co cos( thp trc va chi bu n cos( = 0,90 0,95 (khng bu cao hn vi se khng kinh t va anh hng khng tt ti tinh n inh cua h thng in). Con tha thi ta bu cho cac h gn co cos( cao hn va bu cho n khi co cos( = 0,85 0,90. Cng sut bu s b cho h tiu thu th i nao o c tinh nh sau: Qbi = Qi Pi*tg(i miTrong o : Pi , Qi : la cng sut cua h tiu thu trc khi bu.

tg(i mi : c tinh theo cos(i mi h s cng sut cua h th i sau khi b.Ta chn v tr b ti 2 im 1 v 5:B 5.4 MVAr ti ph ti 1 :Spt1= P1+ jQ1= 20+ j*(12.4- 5.4)= 20+ j*7 MVAcos(1 mi= 0.943B 5.76 MVAr ti ph ti 5:Spt5=P5+ j*Q5= 35+ j*(21.7- 5.76)= 35+ j*15.94 MVAcos(5 mi= 0.91Kt qu b s b nh sau:S liu phu tai123456

Pmax (MW)202528323540

Qmax (MVAR)12.415.517.3619.8421.724.8

Cos(0.850.850.850.850.850.85

Qmax (MVAR)715.517.3619.8415.9424.8

Cos(0.9430.850.850.850.910.85

1.3.Xy dng phng an ni dy.

1.3.1. D kin cac phng an ni dy.+) Phng n 1:

I(2)II

(2)

(1)(2)IV

III

(2)V(1)VI

+) Phng n 2:V

(1)

IVI

(1)(2)

IIIIV

(1)(2)

II

(2)

+) Phng n 3:V

(1)

IVI

(1)(2)

IIIIV

(1)(2)

II

(2)

+) Phng n 4:

V

(1)

IVI

(1)(2)

IIIIV

(1)(2)

II

(2)

+) Phng n 5:V

I(2)II(2)

IIIIV

(1)(2)

V

(2)VI(1)

1.3.2.Phn tch v gi li mt s phng n tnh ton tip:-S hnh tia c u im: s ni dy, b tr thit b n gin; cc ph ti khng lin quan n nhau, s c trn 1 mt ng dy khng nh hng n ng dy khc, tn tht nh hn s lin thng. Tuy vy s hnh tia c nhc im: kho st thit k thi cng mt nhiu thi gian v tn nhiu chi ph.

- S lin thng c u im: kho st thit k gim nhiu so vi s hnh tia, thit b dy dn c chi ph gim. Tuy vy n c nhc im: cn c thm trm trung gian, i hi bo v rle, thit b t ng ho phc tp hn, tin cy cung cp in thp hn so vi s hnh tia.

- Mng kn c u im l tin cy cung cp cao, kh nng vn hnh li linh hot, tn tht ch bnh thng thp. Tuy nhin nhc im ca mng kn l: b tr bo v rle v t ng ho phc tp, khi xy ra s c tn tht li cao, nht l ngun c chiu di dy cp in ln.Da vao cac u nhc im trn, kt hp vi 5 phng an c xy dng ta chon phng an 1 va 5 tip tuc tinh toan.

CAC INH HNG KY THUT C BAN.Do khoang cach gia ngun cung cp in va cac phu tai, hoc gia cac phu tai vi nhau tng i xa nn ta se dung ng dy trn khng cung cp in cho cac phu tai. Va am bao v bn c cung nh kha nng dn in ta s dung loai dy AC truyn tai, con ct thi s dung loai ct thep.Phu tai loai I co yu cu am bao cung cp in mc cao nht phai c cung cp in t mt mach vong kin hoc ng dy l kp. Con i vi phu tai loai II thi chi cn s dung 1 ng dy n cung cp. Chon may bin ap cho cac tram ha ap: vi cac phu tai loai I ta se s dung 2 may bin ap vn hanh song song, con vi phu tai loai II chi cn chon 1 may bin ap.CHNG II

TINH TOAN KINH T - KY THUT, CHON PHNG AN TI U

Tin hnh tnh ton cho 2 phng n.SO SANH CAC PHNG AN V MT KY THUT: La chon in ap tai in.

Ta s dung cng thc kinh nghim sau xac inh in ap inh mc cua ng dy:

(kV)Trong o:

P: La cng sut chuyn tr trn cac ng dy (MW).

L: La khoang cach truyn tai (km).

n: La s l dy song song.

Tinh toan la chon tit din dy dn theo mt kinh t cua dong in ( Jkt ).

Trong o:

Ilv: Dong in lam vic chay trn ng dy (A).

Pijmax, Qijmax : Dong cng sut tac dung va phan khang ln nht chay trn oan dy . n :s mach ng dy. Udm: in ap inh mc (kV). Jkt: Mt kinh t cua dong in ( A/mm2) Sau o da vao tit din kinh t a c tinh trn ta tin hanh chon tit din theo chun: Fchon Fk

Tinh tn tht in ap luc vn hanh binh thng va khi s c nguy him nht. Tn tht in ap trn mt oan ng dy c tinh theo biu thc sau:

Trong o:

P, Q : La dong cng sut tac dung va phan khang chay trn ng dy o.

R, X: La in tr va in khang cua oan dy o.

Udm: La in ap inh mc cua mang in.

Trng hp s c nguy him nht la khi l kep ( hoc mach vong kin) bi t mt l dy ( mt oan ng dy ).

Kim tra phat nong cua dy dn luc s c.

Ta phai tinh c dong in chay trong dy dn cua oan ng dy o luc s c nng n nht ( Isc). Sau o, so sanh tri s tinh c vi dong in cho phep chay trong dy dn o (Icp).

Nu la oan ng dy co l kep thi dong in khi co s c bng 2 ln dong in khi ch phu tai max.

Isc =2* Imaxbt Cac phng an am bao c cac yu cu v ky thut la cac phng an phai thoa man c hai iu kin sau: + in p:

Luc binh thng : Umaxbt% 10%

Luc s c : Umaxbt% 20% + Cac dy dn la chon cho cac oan ng dy cua 2 phng an phai am bao c iu kin phat nong khi co s c: Isc K1.Icp Isc : Dong in ln nht luc s c. Icp: La dong in cho phep lu dai chay qua dy dn. K1: H s hiu chinh theo nhit lam vic khac nhit tiu chun ( ly K1 = 0,88).

Nu nh tit din dy dn a chon ma khng thoa man iu kin trn thi ta phai tng tit din dy cho n khi thoa man.2.1 Tnh ton phn b cng sut s b, chn cp in p

I.Phng an 1.

I.1. Tinh toan phn b cng sut s b, chon cp in ap.

I.1.1. Tinh toan phn b cng sut s b v in p vn hnh li.+) S ni dy ca phng n 1:

I(2)II

(2)

(1)(2)IV

III

(2)V(1)VI

P (MW)Q (MVAr)L (km)U (kV)

N-120742.4382.62

N-22515.531.6290.17

N-32817.362067.79

N-43219.8440101.97

N-53515.9442.

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