CHNG 1: PHN TCH NGUN V PH TI

1.1.S a l

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(1 =10 km x 10 km)Nhng s liu v ph ti. -Li in thit k gm4 ph ti ( t ph ti 1 n ph ti 4).+ Trong c ph ti 1;2;3;thuc h loi I + Ph ti 4 l h loi III -Bng 1.1:S liu tnh ton ca ph ti tnh ton :

Ph tiThuc h loiSmax(MVA)Smin(MVA)cosPmax(MW)Pmin(MW)Qmax(MVAr)Qmin(MVAr)Tmax(h)

1I38170,7813,2623,7810,638313,264500

2I30180,814,41810,814,44500

3I34200,81620,412164800

4III22100,858,511,5895,267838,54000

Tng1246552,1673,76938,706152,16

Trong :

1.2- Phn tch ngun v ph ti1.2.1 Ngun inTrong thit k li in, vic phn tch ngun in nm vng c im v s liu ca ngun, thun li cho vic tnh ton. Ta s dng ngun c cng sut v cng ln:- Cng sut ngun ln (57) ln cng sut ti.

1.2.2 Ph ti

- Mng in m ta cn thit k gm 4 ph ti vi tng cng sut ln nht l :(MVA) v tng cng sut nh nht l :(MVA).- Cc h ph ti loi I bao gm h:1;2;3 l nhng h quan trng, v vy phi d phng chc chn. Mi ph ti phi c cp in bng mt l ng dy kp v hai my bin p lm vic song song m bo cp in lin tc cng nh m bo cht lng in nng mt ch vn hnh.Khi ngng cp in c th lm hng sn phm, h hi thit b gy nh hng ln n hot ng ca ph ti.- Cc h ph ti loi III (h 4) l cc h ph ti t quan trng hn nn gim chi ph u t ta ch cn cp in bng mt ng dy n v mt my bin p.- Yu cu iu chnh in p. Trong mng in thit k cc h 1;2;4 c yu cu iu chnh in p thng. phng php ny lch in p phi tha mn cc ch nh sau:Ch ph ti cc tiu :dUmin% +7.5%Ch ph ti cc i:dUmax% +2.5% Ph ti 3 c yu cu iu chnh in p khc thng nn phm vi chnh in p ch cc i, cc tiu, s c l:Ch ph ti cc tiu :dUmin% = 0 % Ch ph ti cc i : dUmax% = +5 % Ch ph ti s c :dUsc% = 0 +5%

- Tt c cc ph ti u c in p h nh nhau l 35 kV

CHNG 2: D KIN CC PHNG N NI DY2.1.D kin cc phng n ni dy. -Cc ch tiu ch tiu kinh t -k thut ca mng in ph thuc rt nhiu vo s ni dy ,v vy s ca mng in cn phi c chi ph nh nht ,m bo tin cy cung cp in cn thit v cht lng in nng yu cu ca cc h tiu th thun tin v an ton trong vn hnh ,kh nng pht trin trong tng lai v tip nhn cc ph ti mi.Cc h ph ti loi I c cp in bng ng dy hai mch hoc mch vn,cc h ph ti loai III c cp in bng ng dy mt mch.

T s mt bng ca ngun in v cc ph ti cho chng ta c tha ra cc phng n ni dy cho mng in trn.Qua tin hnh nh gi s b chng ta c th gi li 4 phng n sau :

-Phng n ni dy s 1

Khoa H Thng in Bi tp mn hc Li in

3GVHD:Nguyn Vn Thin SV: Bi Ngc Li Lp : T46-H6

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Phng n ni dy s 2

Khoa H Thng in Bi tp mn hc Li in

4GVHD:Nguyn Vn Thin SV: Bi Ngc Li Lp : T46-H6

14

Phng n ni dy s 3

Khoa H Thng in Bi tp mn hc Li in

3GVHD:Nguyn Vn Thin SV: Bi Ngc Li Lp : T46-H6

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Phng n ni dy s 4

Khoa H Thng in Bi tp mn hc Li in

5GVHD:Nguyn Vn Thin SV: Bi Ngc Li Lp : T46-H6

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Khoa H Thng in Bi tp mn hc Li in

5GVHD:Nguyn Vn Thin SV: Phm Minh Phng Lp : T46-H6CHNG 3 CHN IN P NH MC CHO LI IN.

3.1.Chn in p nh mcLa chn cp in p nh mc cho mng in l nhim v rt quan trng, v tr s in p nh hng trc tip n cc chi ph kinh t, k thut ca mng in. chn c cp in p hp l phi tha mn cc yu cu sau: Phi p ng c yu cu m rng ph ti sau ny. m bo tn tht in p t ngun n ph ti. - Khi in p cng cao th tn tht cng sut cng b, s dng t kimloi mu (I nh). Nhng in p cng tng cao th chi ph xy dng mng in cng ln v gi thnh thit b cng tng.V vy phi chn in p nh mc nh th no cho ph hp v kinh t v k thut.Chn in p ti u theo cng thc kinh nghim:

Ui= 4,34.Trong :Ui - in p ng dy th i (kV).li - khong cch t ngun n ph ti th i ( km).Pi- cng sut ln nht trn ng dy th i(MW).

Ta c bng s liu:

Ph tiS mchPmax(MW)li (km)Ui (kV)Um (kV)

1229,6428,28497,29

110

222463,24691,783

3227,253,85295,977

4118,75081,101

T bng s liu trn ta chn in p nh mc cho mng in l Um = 110kV.

3.2 Tnh ton chn tit din dy dn -Do mng in thit k c Um =110kV. Tit din dy dn thng c chn theo phng php mt kinh t ca dng in Jkt.

Fkt = (*)Vi Imax l dng in cc i trn ng dy trong ch lm vic bnh thng, c xc nh theo cng thc:

Imax = = Trong :Jkt - mt kinh t ca dng in.Um - in p nh mc ca dng in. (kV)Smaxi - cng sut trn ng dy th i khi ph ti cc i.(MVA)n - s l ng dy. Ta s dng dy nhm li thp ( AC ) truyn ti vi thi gian s dng cng sut cc i ca ph ti l t : 3000-5000h , nn ta c mt kinh t ca dng in Jkt = 1,1 A/mm2 . Da vo tit din dy dn tnh theo cng thc (*), tit hnh chn tit din tiu chun gn nht v kim tra cc iu kin v s to thnh vng quang. bn c v ng dy v iu kin php nng ca dy dn.- Kim tra iu kin vng quang. Theo iu kin, tit din dy dn khng c nh hn tr s cho php i vi mi cp in p.Vi cp in p 110kV, khng xut hin vng quang tit din dy dn ti thiu c php l 70mm2 .-Kim tra pht nng dy dn.Theo iu kin:Isc max < k. Icp.Trong :Icp - dng in cho php ca dy dn, n ph thuc vo bn cht v tit din ca dy.k - h s quy i theo nhit Khc = 0.88 ng vi nhit l 25oc.i vi ng dy kp : Isc max = 2.Ibt max < 0.88.Icp.i vi ng dy n khi c s c s dn n mt in.3.3 Tiu chun tn tht in p -Cc mng in 1 cp in p t tiu chun k thut nu trong ch ph ti cc i cc tn tht in p ln nht trong ch lm vic bnh thng v ch s c nm trong khong sau y:

- i vi nhng mng in phc tp (mng in kn), c th chp nhn tn tht in p ln nht trong ch ph ti cc i v ch s c nm trong khong:

Trong Ubt max , Usc max l tn tht in p lc bnh thng v lc s c nng n nht.Ta tnh tn tht theo cng thc:

Ui (%) = %Pi ,Qi l cng sut tc dng v cng sut phn khng trn ng dy th i (MW, MVAr).

Ri, Xi l in tr tc dng v in khng ca ng dy th i()

CHNG 4: TNH TON CH TIU KINH T ,K THUT CHO TNG PHNG N 4.1.TNH TON K THUT 4.1.1.-Phng n ni dy s 1

Khoa H Thng in Bi tp mn hc Li in

8GVHD:Nguyn Vn Thin SV: Bi Ngc Li Lp : T46-H6

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1. La chn tit din dy dna - on ng dy A-1-Chn tit din dy dn. SA-1 = Smax1 = 38 (MVA)

Imax A-1 == (A)

Fkt = = mm2-Chn dy dn loi AC- 95,c tit din chun l 95mm2 v dng in cho php Icp=330A.- Kim tra theo iu kin vng quang: dy dn chn c:Ftc= 70 mm2 ( tha mn iu kin).- Kim tra theo iu kin pht nng: v on A-1 l ng dy kp nn khi hng mt l th l cn li vn phi lm vic bnh thng.Isc = 2.Ibt max = 2.99,7241= 199,448(A)Isc < 0,88.Icp = 290,4A ( tha mn iu kin ).-Kim tra tn tht in p trn ng dy.

Vi loi ng dy AC- 95 ta c: ro=0,33/km, xo=0,429/kmin tr v in khng ng dy :

R =ro.l =0,33.28,284= 4,6669().

X =xo .l =0,429.28,284= ().- Tn tht in p ch bnh thng :

U1bt % = =%- Tn tht in p ch s c:

U1sc % =2. U1bt % = 2. % = %Bng chn tit din dy dnv iu kin pht nng:

on ng dyS mch

ImaxFktLoi dyIcpIsc(A)k,Icp(A)

A-123899,724190,658AC-95330199,448290,4

A-223078,729671,572AC-70265

A-323489,226981,115AC-70265178,454233,2

A-4122115,47104,97AC-95330230,94290,4

Theo s liu tnh ton bng trn,cc dy dn chn tha mn iu kin pht nng.

Bng tn tht in p:on ng dyS mchli (km)ro (/km)xo (/km)R()X()Ubt%Usc%

A-1228,2840,330,4294,66696,0672,3364,671

A-2263,2460,450,4414,2313,9144,8929,785

A-3253,8520,450,4412,11711,8474,7219,442

A-41500,330,42916,521,454,604

Theo bng trn ta thy:Ubt max%= 4,892