Đồ án tốt nghiệp lưới điện - Đại học Điện lực

TP ON IN LC VIT NAM

TRNG I HC IN LC

KHOA H THNG IN

N TT NGHIPTHIT K LI IN, TNH TON TRO LU CNG

SUT V LA CHN U PHN P MY BIN P BNGCHNG TRNH PSS/E

Ging vin hng dn: TS.NGUYN NG TONSinh vin thc hin: NGUYN VN NGCNgnh: CNG NGH K THUT INChuyn ngnh: H THNG INLp: 5 - H3Kho: 5

H Ni, thng 1 nm 2015

LI NI U

S nghip cng nghip ha, hin i ha t nc ta trong giai on hin nayyu cu tng khng ngng sn lng in. thc hin c iu cn phi phttrin, m rng cc nh my in cng nh cc h thng in cng sut ln v mttrong nhng nhim v tt yu l thit k li in. Thit k l mt lnh vc quantrng v kh khn trong cng vic ca ngi k s H thng in v cc mng vh thng in thit k cn phi t c cc yu cu v k thut, hp l v kinh t,linh hot v an ton trong vn hnh.

Trong nhiu nm gn y, cc ngnh khoa hc k thut pht trin mnh m, nhtl cng ngh thng tin, cng ngh phn mm to ra nhiu sn phm cht lngc ng dng rng ri trong ngnh in, c bit l chng trnh PSS/E. Chngtrnh ny c rt nhiu tnh nng tuy nhin trong phm vi n ny, tc gi ch sdng PSS/E tnh ton tro lu cng sut v chn u phn p cho cc my binp phc v cho vic thit k li in ca mnh.

Mc d trong bn n ny c mt s chi tit c n gin ho nhng yl nhng c s quan trng cho vic thit k mt h thng in ln.

n gm c by chng:

Chng 1: Cn bng cng sut v xut phng n ni dy.

Chng 2: Tnh ton cc ch tiu k thut.

Chng 3: So snh kinh t v chn phng n ti u.

Chng 4: La chn my bin p, s trm bin p v s ni in.

Chng 5: Tnh ton ch xc lp bng chng trnh PSS/E.

Chng 6: iu chnh in p trong mng in.

Chng 7: Tnh ton ch tiu kinh t - k thut ca mng in.

Trong qu trnh thc hin n, do kin thc v thi gian b hn ch nn khngth trnh khi nhng sai st, em mong nhn c s ch bo, gp ca cc thy cgio bn n tt nghip ny c hon thin hn.

LI CM N

Li u tin ca n, em xin gi li cm n su sc ti thy gio hng dnTS.Nguyn ng Ton, thy giao ti v tn tnh hng dn em trong qu trnhhon thnh kha lun tt nghip. Nhn dp ny em xin gi li cm n chn thnh titon th cc thy c gio ca trng i hc in lc, c bit l cc thy c giotrong khoa H thng in tn tnh ging dy v gip chng em trong sut qutrnh hc tp.

Xin chn thnh cm n cc thy c gio c, phn bin v gp em cth hon thin quyn n ny.

ng thi, ti xin cm n cc bn trong lp 5 - H3 nhit tnh gip titrong qu trnh hc tp ti lp.

H Ni, thng 01 nm 2015Sinh vin

Nguyn Vn Ngc

NHN XT CA GIO VIN HNG DN

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NHN XT CA GIO VIN PHN BIN

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Mc lc

LI NI U . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

LI CM N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

NHN XT CA GIO VIN HNG DN . . . . . . . . . . . . . iii

NHN XT CA GIO VIN PHN BIN . . . . . . . . . . . . . . iv

Chng 1. CN BNG CNG SUT V XUT PHNG NNI DY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1. Phn tch ngun cung cp v ph ti . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1.1. Ngun cung cp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1.2. Ph ti in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2. Cn bng cng sut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.2.1. Cn bng cng sut tc dng . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.2.2. Cn bng cng sut phn khng. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.2.3. Cc ch lm vic ca ngun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.3. xut cc phng n ni dy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.3.1. C s xut cc phng n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.3.2. xut cc phng n ni dy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

1.4. Kt lun chng 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Chng 2. TNH TON CC CH TIU K THUT. . . . . . . . . . . . . . . . 20

2.1. Cc ch tiu k thut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202.1.1. Chn in p nh mc ca mng in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202.1.2. La chn tit din dy dn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212.1.3. Tnh tn tht in p, tn tht cng sut . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

v

2.2. Tnh ton cho phng n 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242.2.1. Chn in p nh mc ca mng in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242.2.2. La chn tit din dy dn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272.2.3. Tnh tn tht in p, tn tht cng sut . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29





2.7. So snh cc ch tiu k thut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

2.8. Kt lun chng 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Chng 3. SO SNH KINH T V CHN PHNG N TI U . . . 45

3.1. Ch tiu kinh t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453.1.1. Vn u t xy dng mng in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453.1.2. Chi ph vn hnh hng nm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463.1.3. Chi ph tnh ton hng nm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

3.2. Tnh ton cho phng n 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483.2.1. Vn u t xy dng mng in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483.2.2. Chi ph vn hnh hng nm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493.2.3. Chi ph tnh ton hng nm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

3.3. Tnh ton cho phng n 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493.3.1. Vn u t xy dng mng in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493.3.2. Chi ph vn hnh hng nm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

GVHD: T.S Nguyn ng Ton vi SVTH: Nguyn Vn Ngc

3.3.3. Chi ph tnh ton hng nm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.4. Tnh ton cho phng n 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503.4.1. Vn u t xy dng mng in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503.4.2. Chi ph vn hnh hng nm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513.4.3. Chi ph tnh ton hng nm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

3.5. So snh cc ch tiu kinh t, chn phng n ti u . . . . . . . . . . . . . 52

3.6. Kt lun chng 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Chng 4. LA CHNMY BIN P, S TRM BIN P VS NI IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

4.1. Chn s lng v cng sut my bin p . . . . . . . . . . . . . . . . . . . . . . . . 544.1.1. Chn s lng v cng sut my bin p trong cc trm tng p ca nhmy in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544.1.2. Chn s lng v cng sut ca my bin p trong cc trm h p . . . . . 56

4.2. Chn s cc trm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584.2.1. S trm tng p ca nh my nhit in . . . . . . . . . . . . . . . . . . . . . . . . . . 584.2.2. S trm bin p trung gian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594.2.3. S trm bin p gim p . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

4.3. Kt lun chng 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Chng 5. TON CH XC LP BNG CHNG TRNHPSS/E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

5.1. Gii thiu tng quan v chng trnh PSS/E . . . . . . . . . . . . . . . . . . . . 63

5.2. Tnh ton trong h n v tng i . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645.2.1. ng dy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645.2.2. My bin p hai cun dy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655.2.3. My bin p t ngu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665.2.4. in p cc nt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 675.2.5. Ph ti . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

5.3. M phng mng in thit k vi nh my nhit in l nt PV . . 695.3.1. Ch ph ti cc i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695.3.2. Ch ph ti cc tiu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755.3.3. Ch s c. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

5.4. Kt lun chng 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

GVHD: T.S Nguyn ng Ton vii SVTH: Nguyn Vn Ngc

Chng 6. IU CHNH IN P TRONGMNG IN. . . . . . . . . . . 85

6.1. Ch ph ti cc i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 876.1.1. Nhp thng s cho cc phn t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 876.1.2. Tnh ton chn u phn p . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 876.1.3. Tnh ton tro lu cng sut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

6.2. Ch ph ti cc tiu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 926.2.1. Nhp thng s cho cc phn t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 926.2.2. Tnh ton chn u phn p . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 936.2.3. Tnh ton tro lu cng sut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

6.3. Ch s c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

6.4. Kt lun chng 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Chng 7. TNH TON CC CH TIU KINH T-K THUT CAMNG IN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

7.1. Vn u t xy dng mng in . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

7.2. Tn tht cng sut tc dng trong mng in . . . . . . . . . . . . . . . . . . 101

7.3. Tn tht in nng trong mng in. . . . . . . . . . . . . . . . . . . . . . . . . . . 101

7.4. Tnh cc chi ph v gi thnh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1027.4.1. Chi ph vn hnh hng nm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1027.4.2. Chi ph tnh ton hng nm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1037.4.3. Gi thnh truyn ti in nng . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1037.4.4. Gi thnh xy dng 1MW cng sut ph ti trong ch ph ti cci . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

KT LUN CHUNG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

TI LIU THAM KHO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

GVHD: T.S Nguyn ng Ton viii SVTH: Nguyn Vn Ngc

Danh sch hnh v

1.1 Bn v tr ca ngun v cc ph ti in . . . . . . . . . . . . . . . . 101.2 S mch in phng n 1 . . . . . . . . . . . . . . . . . . . . . . . 121.3 S mch in phng n 2 . . . . . . . . . . . . . . . . . . . . . . . 131.4 S mch in phng n 3 . . . . . . . . . . . . . . . . . . . . . . . 141.5 S mch in phng n 4 . . . . . . . . . . . . . . . . . . . . . . . 151.6 S mch in phng n 5 . . . . . . . . . . . . . . . . . . . . . . . 161.7 S mch in phng n 6 . . . . . . . . . . . . . . . . . . . . . . . 171.8 S mch in phng n 7 . . . . . . . . . . . . . . . . . . . . . . . 18

2.1 S mch in phng n 1 . . . . . . . . . . . . . . . . . . . . . . . 252.2 S mch in phng n 2 . . . . . . . . . . . . . . . . . . . . . . . 312.3 S mch in phng n 3 . . . . . . . . . . . . . . . . . . . . . . . 352.4 S mch in phng n 4 . . . . . . . . . . . . . . . . . . . . . . . 382.5 S mch in phng n 5 . . . . . . . . . . . . . . . . . . . . . . . 41

4.1 S ni in nh my in . . . . . . . . . . . . . . . . . . . . . . . 554.2 S trm tng p nh my in . . . . . . . . . . . . . . . . . . . . . 594.3 S ni in trm trung gian . . . . . . . . . . . . . . . . . . . . . . 604.4 (a) S cu trong; (b) S cu ngoi . . . . . . . . . . . . . . . . . 614.5 S cu y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624.6 S b ng dy - my bin p . . . . . . . . . . . . . . . . . . . . 62

5.1 Thng s cc nt ch ph ti cc i . . . . . . . . . . . . . . . . 695.2 Thng s ca nh my ch ph ti cc i . . . . . . . . . . . . . 705.3 Thng s ca my pht ch ph ti cc i . . . . . . . . . . . . . 705.4 Thng s ca ph ti khi cc i . . . . . . . . . . . . . . . . . . . . . 70

ix

5.5 Thng s ca cc ng dy ti in . . . . . . . . . . . . . . . . . . . 715.6 Thng s ca cc my bin p hai cun dy . . . . . . . . . . . . . . . 715.7 Thng s ca my bin p t ngu . . . . . . . . . . . . . . . . . . . . 715.8 Thng s cc nt sau khi tnh ton ch ph ti cc i . . . . . . . 725.9 Cng sut pht ca nh my v h thng . . . . . . . . . . . . . . . . . 725.10 S m phng mng in ch cc i vi nt nh my l PV . . . 735.11 Thng s cc nt ch ph ti cc tiu . . . . . . . . . . . . . . . . 765.12 Thng s ca nh my ch ph ti cc tiu . . . . . . . . . . . . . 775.13 Thng s ca my pht ch ph ti cc tiu . . . . . . . . . . . . . 775.14 Hp thoi chn chc nng Scale . . . . . . . . . . . . . . . . . . . . . 775.15 Hp thoi iu chnh cng sut ph ti v cng sut pht . . . . . . . . 785.16 Thng s ca ph ti khi cc tiu . . . . . . . . . . . . . . . . . . . . . 785.17 Thng s cc nt sau khi tnh ton ch ph ti cc tiu . . . . . . . 795.18 Cng sut pht ca nh my v h thng . . . . . . . . . . . . . . . . . 795.19 S m phng mng in ch cc tiu vi nt nh my l PV . . 805.20 Thng s cc nhnh khi s c mt l ng dy 2 - HT . . . . . . . . . 825.21 in p nt ph ti 2 khi s c mt l ng dy 2 - HT . . . . . . . . 835.22 Thng s cc nhnh khi s c mt l ng dy N - 2 . . . . . . . . . 835.23 in p nt ph ti 2 khi s c mt l ng dy N - 2 . . . . . . . . 83

6.1 Thng s my bin p hai cun dy ch ph ti cc i . . . . . . . 886.2 Thng s my bin p hai cun dy ch ph ti cc i (tip) . . . 886.3 in p cc nt sau khi tnh ton ch ph ti cc i . . . . . . . . 896.4 in p u iu chnh in p my bin p . . . . . . . . . . . . . . . 896.5 Thng s my bin p hai cun dy ch ph ti cc tiu . . . . . . 926.6 Thng s my bin p hai cun dy ch ph ti cc tiu (tip) . . . 926.7 in p cc nt sau khi tnh ton chn u phn p . . . . . . . . . . . 936.8 in p u iu chnh in p my bin p ch ph ti cc tiu . . 936.9 Thng s my bin p hai cun dy ch s c . . . . . . . . . . . . 966.10 Thng s my bin p hai cun dy ch s c (tip) . . . . . . . . 96

GVHD: T.S Nguyn ng Ton x SVTH: Nguyn Vn Ngc

Danh sch bng

1.1 Thng s ca cc ph ti . . . . . . . . . . . . . . . . . . . . . . . . . 31.2 Bng tng kt ch lm vic ca ngun . . . . . . . . . . . . . . . . 91.3 Khong cch t cc ngun n cc ph ti . . . . . . . . . . . . . . . . 111.4 Khong cch gia cc ph ti gn nhau . . . . . . . . . . . . . . . . . . 11

2.1 in p tnh ton v in p nh mc ca mng in phng n 1 . . . 262.2 Tit din tiu chun ca cc ng dy trong phng n 1 . . . . . . . . 282.3 Thng s cc ng dy phng n 1 . . . . . . . . . . . . . . . . . . 292.4 Tn tht in p phn trm, tn tht cng sut phng n 1 . . . . . . . 302.5 in p tnh ton v in p nh mc ca mng in phng n 2 . . . 322.6 Tit din tiu chun ca cc ng dy trong phng n 2 . . . . . . . . 322.7 Thng s cc ng dy phng n 2 . . . . . . . . . . . . . . . . . . 332.8 Tn tht in p phn trm, tn tht cng sut phng n 2 . . . . . . . 342.9 in p tnh ton v in p nh mc ca mng in phng n 3 . . . 352.10 Tit din tiu chun ca cc ng dy trong phng n 3 . . . . . . . . 362.11 Thng s cc ng dy phng n 3 . . . . . . . . . . . . . . . . . . 362.12 Tn tht in p phn trm, tn tht cng sut phng n 3 . . . . . . . 372.13 in p tnh ton v in p nh mc ca mng in phng n 4 . . . 382.14 Tit din tiu chun ca cc ng dy trong phng n 4 . . . . . . . . 392.15 Thng s cc ng dy phng n 4 . . . . . . . . . . . . . . . . . . 392.16 Tn tht in p phn trm, tn tht cng sut phng n 4 . . . . . . . 402.17 in p tnh ton v in p nh mc ca mng in phng n 5 . . . 412.18 Tit din tiu chun ca cc ng dy trong phng n 5 . . . . . . . . 422.19 Thng s cc ng dy phng n 5 . . . . . . . . . . . . . . . . . . 422.20 Tn tht in p phn trm, tn tht cng sut phng n 5 . . . . . . . 43

xi

2.21 So snh ch tiu k thut cc phng n . . . . . . . . . . . . . . . . . 44

3.1 Gi thnh 1km ng dy trn khng mt mch in p 110kV . . . . . 463.2 Vn u t xy dng ng dy phng n 1 . . . . . . . . . . . . . . . 483.3 Ch tiu kinh t mng in phng n 1 . . . . . . . . . . . . . . . . . 493.4 Vn u t xy dng ng dy phng n 3 . . . . . . . . . . . . . . . 503.5 Ch tiu kinh t mng in phng n 3 . . . . . . . . . . . . . . . . . 513.6 Vn u t xy dng ng dy phng n 4 . . . . . . . . . . . . . . . 513.7 Ch tiu kinh t mng in phng n 4 . . . . . . . . . . . . . . . . . 523.8 Tng hp cc ch tiu kinh t - k thut ca cc phng n so snh . . . 52

4.1 Thng s ca my bin p trong s b . . . . . . . . . . . . . . . . 564.2 Thng s k thut ca my bin p t ngu . . . . . . . . . . . . . . . 564.3 S lng, cng sut my bin p trong cc trm h p . . . . . . . . . . 584.4 Thng s ca my bin p trong cc trm h p . . . . . . . . . . . . . 58

5.1 Thng s ng dy dng n v tng i . . . . . . . . . . . . . . . 655.2 Thng s my bin p hai cun dy dng n v tng i . . . . . . . 665.3 Thng s my bin p t ngu dng n v tng i . . . . . . . . . . 685.4 Thng s ca cc ph ti . . . . . . . . . . . . . . . . . . . . . . . . . 685.5 Tro lu cng sut trong mng in ch cc i khi xem nt

nh my l PV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745.6 Cng sut ph ti cc tiu v cng sut ph ti gii hn . . . . . . . . . 755.7 Tro lu cng sut trong mng in ch cc tiu khi xem nt

nh my l PV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 815.8 in p ti cc trm bin p 1 v 4 khi s c mt l ng dy N - 2 . 845.9 in p ti cc trm bin p ch sau s c . . . . . . . . . . . . . 84

6.1 Thng s iu chnh in p my bin p thng . . . . . . . . . . . . 866.2 Thng s iu chnh in p my bin p c b iu chnh in p

di ti . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 866.3 in p ph ti v u phn p ca cc my bin p ch ph

ti cc i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906.4 Tro lu cng sut trong mng in ch ph ti cc i sau khi

chn u phn p . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916.5 in p ph ti v u phn p ca cc my bin p ch ph

ti cc tiu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

GVHD: T.S Nguyn ng Ton xii SVTH: Nguyn Vn Ngc

6.6 Tro lu cng sut trong mng in ch ph ti cc tiu saukhi chn u phn p . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

6.7 in p ph ti v u phn p ca my bin p khi ngng lm vicmt mch ng dy N - 2 . . . . . . . . . . . . . . . . . . . . . . . 97



6.10 Khi ngng lm vic mt mch ng dy N - 6 . . . . . . . . . . . . 986.11 Tng hp u phn p cc ch vn hnh trong mng in . . . . . 98

7.1 Tng vn u t cc trm bin p trong mng in . . . . . . . . . . . . 1017.2 Ch tiu kinh t - k thut ca mng in thit k . . . . . . . . . . . . 104

GVHD: T.S Nguyn ng Ton xiii SVTH: Nguyn Vn Ngc

Chng 1

CN BNG CNG SUT V XUT PHNG N NIDY

1.1. Phn tch ngun cung cp v ph ti

1.1.1. Ngun cung cp

1.1.1.1. H thng in

H thng in c cng sut v cng ln. V vy cn phi c s lin kt gia hthng v nh my in c th trao i cng sut gia hai ngun cung cp khicn thit, m bo cho h thng thit k lm vic bnh thng trong ch lm vicbnh thng cng nh khi xy ra s c. Mt khc, v h thng in c cng sut vcng ln nn chn h thng l nt cn bng cng sut v nt c s v in p, ngthi khng cn phi d tr cng sut trong nh my nhit in, ni cch khc cngsut tc dng v phn khng d tr s c ly t h thng in.

1.1.1.2. Nh my nhit in

Nh my nhit in c nhiu u im nh thi gian xy dng ngn (3 4 nm),c th s dng c cc nhin liu r tin nh than cm, than ba cc khu khai thc

1

than, du nng cc nh my lc du,. . . . Tuy nhin, nh my nhit in cng cnhiu nhc im nh khi ng chm (t 6 8 gi mi t cng sut nh mc),iu chnh cng sut kh, khi gim t ngt cng sut phi thi hi nc ra ngoinn va mt nng lng va mt nc. V vy, nhit in thng c s dng ph y.

i vi nhit in, cc my pht lm vic n nh khi cng sut ph tiP 70%Pm, khi cng sut ph ti P < 30%Pm cc my pht ngng lm vic.Ngoi ra, cng sut pht kinh t ca cc my pht thng bng (70 90%)Pm.

Theo ti thit k, nh my nhit in c bn t my pht. Mi my pht ccng sut nh mc Pm = 100 MW; cos = 0,8; Um = 10,5 kV. Nh vy, tng cngsut nh mc ca ton nh my in bng 400 MW.

1.1.2. Ph ti in

Trong mng in thit k c 7 ph ti. Trong :

- H ph ti loi I (ph ti 2, 3, 5, 6 v 7) l cc ph ti quan trng. Khi cs c ngng cung cp in s gy nguy him cho tnh mng con ngi, nhhng n an ninh, trt t, chnh tr, lm hng thit b - sn phm hng lotgy thit hi ln cho nn kinh t quc dn. V vy, i vi cc ph ti ny, yucu cung cp in lin tc ngay c khi s c, thi gian mt in ti a chophp bng thi gian ng ngun d phng (khong 5 7 giy). Do , hloi I phi c cung cp in bng ng dy hai mch hoc mch vng.

- H ph ti loi III (ph ti 1 v 4) l cc ph ti khng my quan trng. Nghal cc ph ti m vic mt in khng gy ra nhng hu qu qu nghimtrng. Do vy, h ph ti loi ny c cung cp in bng dy n v chophp ngng cung cp in trong thi gian cn thit sa cha s c hay thayth phn h hng ca mng in nhng khng qu 1 ngy.

Tt c cc ph ti trn u c h s cos = 0, 9. Thi gian s dng cng sutcc i Tmax = 5000h. in p nh mc ca mng in th cp ca cc trm hp bng 22 kV. Ph ti cc tiu bng 75% ph ti cc i. Cc ph ti u c yucu iu chnh in p khc thng, ngoi tr ph ti 3 v 5 c yu cu iu chnhin p thng.

Cng sut yu cu ca cc ph ti trong ch cc i v cc tiu c chotrong bng 1.1.

GVHD: T.S Nguyn ng Ton 2 SVTH: Nguyn Vn Ngc

Bng 1.1: Thng s ca cc ph ti

H tiu Smax = Pmax + jQmax Smax Smin = Pmin + jQmin Sminth (MVA) (MVA) (MVA) (MVA)

1 20 + j9,69 22,22 15 + j7,26 16,672 40 + j19,37 44,44 30 + j14,53 33,333 25 + j12,11 27,78 18,75 + j9,08 20,834 25 + j12,11 27,78 18,75 + j9,08 20,835 30 + j14,53 33,33 22,50 + j10,90 256 30 + j14,53 33,33 22,50 + j10,90 257 120 + j58,12 133,33 90 + j43,59 100

Tng 290 + j140,45 322,22 217,5 + j105,34 241,67

1.2. Cn bng cng sut

1.2.1. Cn bng cng sut tc dng

Cng sut tc dng ca cc ph ti lin quan vi tn s ca h thng in. Tns trong h thng s thay i khi s cn bng cng sut trong h thng in b phv. Thiu cng sut tc dng s dn n gim tn s v ngc li, tha cng suttc dng dn n tng tn s. V vy ti mi thi im trong ch xc lp ca hthng, cc nh my ca h thng cn phi pht cng sut cn bng vi cng sutca cc h tiu th, k c cc tn tht cng sut trong mng in, ngha l cn phithc hin ng s cn bng gia cng sut pht v cng sut tiu th.

Ngoi ra, m bo cho h thng vn hnh bnh thng, cn phi c d trnht nh ca cng sut tc dng trong h thng. D tr trong h thng in l mtvn quan trng, lin quan n vn hnh cng nh s pht trin ca h thng.

V vy, phng trnh cn bng cng sut tc dng trong ch ph ti cc ii vi h thng in thit k c dng:

PNMD + PHT = Ptt = mPmax + P + Ptd + Pdt (1.1)

trong :

- PNMD - tng cng sut tc dng do nh my in pht ra (MW)

- PHT - cng sut tc dng ly t h thng (MW)

- Ptt - cng sut tiu th trong mng in (MW)


- m - h s ng thi xut hin cc ph ti cc i (lym = 1)

- Pmax - tng cng sut ca cc ph ti trong ch cc i (MW)

- P - tng tn tht cng sut trong mng in, khi tnh s b c th lyP = 5%Pmax

- Ptd - cng sut t dng ca nh my in (MW)

- Pdt - cng sut d tr trong h thng, khi cn bng s b c th lyPdt = 10%Pmax, ng thi cng sut d tr cn phi bng cng sutnh mc ca t my pht ln nht i vi h thng in khng ln. Tuynhin, do h thng in c cng sut v cng ln nn cng sut d tr ly h thng, ngha l Pdt = 0

Tng cng sut tc dng ca cc ph ti khi cc i c xc nh t bng 1.1bng:

Pmax = 290MW

Tng tn tht cng sut trong mng in c gi tr:

P = 5%Pmax = 0, 05.290 = 14, 5MW

Tng cng sut do nh my in pht ra bng:

PNMD = 4.Pm = 4.100 = 400MW

Cng sut t dng trong nh my nhit in c th c tnh theo cng thc:

Std =%100 .Sm.(0, 4 + 0, 6.

SNMDSm

)

= %100 .Pmcos.(0, 4 + 0, 6.

PNMDPm

)(1.2)

trong :

- % - lng in phn trm t dng

- Sm - tng cng sut pht nh mc ca nh my in (MWA)

- SNMD - cng sut pht ca nh my in trong tng ch vn hnh (MVA)

- Pm - tng cng sut tc dng nh mc ca nh my in (MW)


- cos - h s cng sut nh my in

- PNMD - cng sut pht tc dng ca nh my in trong tng ch vnhnh (MW)

p dng cng thc 1.2, ta c cng sut t dng ca nh my in bng:

Std =%100 .

Pmcos.(0, 4 + 0, 6.

PNMDPm

)

= 10100 .4000, 8 .(0, 4 + 0, 6.

400400) = 50MVA

Vy, cng sut tc dng t dng ca nh my c gi tr:

Ptd = Std. costd = 50.0, 75 = 37, 5MW

Cng sut tiu th trong mng in c gi tr:

Ptt = mPmax + P + Ptd = 290 + 14, 5 + 37, 5 = 342MW

Nh vy, h thng cn cung cp lng cng sut cho cc ph ti bng:

PHT = Ptt PNMD = 342 400 = 58MW

Du "-" th hin rng nh my pht tha cng sut tc dng, lng cng suttha ny c a v h thng vi gi tr l 58 MW.

1.2.2. Cn bng cng sut phn khng

Sn xut v tiu th in nng bng dng in xoay chiu i hi s cn bnggia in nng sn xut ra v in nng tiu th ti mi thi im. S cn bng ihi khng nhng ch i vi cng sut tc dng m c i vi cng sut phn khng.

Cn bng cng sut tc dng gi cho tn s bnh thng trong h thng in,nhng mun gi cho in p bnh thng cn phi c s cn bng cng sut phnkhng. Nu cng sut phn khng pht ra ln hn cng sut phn khng tiu thth in p trong mng s tng, ngc li nu thiu cng sut phn khng, in ptrong mng s gim. V vy, m bo cht lng cn thit ca in p cn phitin hnh cn bng cng sut phn khng.

Phng trnh cn bng cng sut phn khng trong mng in thit k c dng:

QNMD+QHT = Qtt = mQmax+QLQC+QB+Qtd+Qdt (1.3)

trong :


- QNMD - tng cng sut phn khng do nh my in pht ra (MVAr)

- QHT - cng sut phn khng ly t h thng (MVAr)

- Qtt - tng cng sut phn khng tiu th trong mng in

- Qmax - tng cng sut phn khng ca cc ph ti trong ch cc i(MVAr)

- QL - tng tn tht cng sut phn khng trong cm khng ca cc ngdy trong mng in (MVAr)

- QC - tng cng sut phn khng do in dung ca cc ng dy sinh ra,khi tnh s b ly QL = QC

- QB - tng tn tht cng sut phn khng trong cc trm bin p, trongtnh ton s b ly QB = 15%Qmax

- Qtd - cng sut phn khng t dng trong nh my in (MVAr)

- Qdt - cng sut phn khng d tr trong h thng in. i vi mng inthit k, cng sut Pdt s ly h thng, ngha l Qdt = 0

Tng cng sut phn khng ca cc ph ti trong ch cc i c xc nhtrong bng 1.1 c gi tr:

Qmax = 140, 45MV ar

Tng tn tht cng sut phn khng trong cc my bin p h p bng:

QB = 15%Qmax = 0, 15.140, 45 = 21, 07MV ar

Tng cng sut phn khng t dng trong nh my in c gi tr:

Qtd = Ptd.tgtd = 37, 5.0, 88 = 33MV ar

Tng cng sut phn khng tiu th trong mng in bng:

Qtt = Qmax + QB +Qtd +Qdt = 140, 45 + 21, 07 + 33 = 194, 52MV ar

Tng cng sut phn khng do nh my in pht ra c gi tr:

QNMD = PNMD.tgNMD = 400.0, 75 = 300MV ar

Ta thy rng, tng cng sut phn khng do nh my in pht ra ln hn tngcng sut phn khng tiu th trong mng in do h thng khng cn cung cpcng sut phn khng cho cc ph ti.


1.2.3. Cc ch lm vic ca ngun

1.2.3.1. Ch ph ti cc i

Khi ph ti cc i, ta cho c bn t my u vn hnh, mi t my pht 85%cng sut nh mc. Nh vy, tng cng sut tc dng pht ra ca nh my inbng:

PNMD = 4.0, 85.Pm = 4.0, 85.100 = 340MW

p dng cng thc 1.2, ta c cng sut t dng ca nh my in c gi tr:

Std =%100 .

Pmcos.(0, 4 + 0, 6.

PNMDPm

)

= 10100 .4000, 8 .(0, 4 + 0, 6.

340400) = 45, 5MVA


Ptd = Std. costd = 45, 5.0, 75 = 34, 13MW

Lng cng sut pht ln li ca nh my in bng:

PF = PNMD Ptd = 340 34, 13 = 305, 87MWQF = QNMD Qtd = 340.0, 75 34, 13.0, 88 = 224, 97MVAr

T bng 1.1, ta c cng sut yu cu ca ph ti c gi tr:

Pyc = Pmax + P = 290 + 0, 05.290 = 304, 5MWQyc = Qmax + QB = 140, 45 + 0, 15.140, 45 = 161, 52MVAr


PHT = Pyc PF = 304, 5 305, 87 = 1, 37MWTa thy rng lng cng sut phn khng do nh my pht ra ln hn lng cng

sut phn khng yu cu ca ph ti, v vy ch ph ti cc i, h thng khngcn cung cp cng sut phn khng cho cc ph ti.

1.2.3.2. Ch ph ti cc tiu

Khi ph ti cc tiu, d kin ngng mt t my, ba t my cn li pht 85% cngsut nh mc. Nh vy, tng cng sut tc dng pht ra ca nh my in bng:

PNMD = 3.0, 85.Pm = 3.0, 85.100 = 255MW



Std =%100 .

Pmcos.(0, 4 + 0, 6.

PNMDPm

)

= 10100 .4000, 8 .(0, 4 + 0, 6.

255400) = 39, 13MVA


Ptd = Std. costd = 39, 13.0, 75 = 29, 35MW



T bng 1.1, ta c cng sut yu cu ca ph ti c gi tr:

Pyc = Pmin + P = 217, 5 + 0, 05.217, 5 = 228, 38MWQyc = Qmin + QB = 105, 34 + 0, 15.105, 34 = 121, 14MVAr


PHT = Pyc PF = 228, 38 225, 65 = 2, 73MW

Ta thy rng lng cng sut phn khng do nh my pht ra ln hn lngcng sut phn khng yu cu ca ph ti, v vy ch ph ti cc tiu, h thngkhng cn cung cp cng sut phn khng cho cc ph ti.

1.2.3.3. Ch s c

Khi s c ngng mt t my, cc my cn li pht 100% cng sut nh mc.Nh vy, tng cng sut tc dng pht ra ca nh my in bng:

PNMD = 3.Pm = 3.100 = 300MW


Std =%100 .

Pmcos.(0, 4 + 0, 6.

PNMDPm

)

= 10100 .4000, 8 .(0, 4 + 0, 6.

300400) = 42, 5MVA



Ptd = Std. costd = 42, 5.0, 75 = 31, 88MW



mc 1.2.3.1, ta c cng sut yu cu ca ph ti c gi tr:

Pyc = 304, 5MW ; Qyc = 161, 52MVAr


PHT = Pyc PF = 304, 5 300 = 4, 5MW

Ta thy rng lng cng sut phn khng do nh my pht ra ln hn lng cngsut phn khng yu cu ca ph ti, v vy ch s c, h thng khng cn cungcp cng sut phn khng cho cc ph ti.

T cc kt qu trn ta c bng 1.2 tng kt s b ch lm vic ca ngun.

Bng 1.2: Bng tng kt ch lm vic ca ngun

Ch vn hnh Nh my nhit in H thng

Ph ti cc i- Bn t my lm vic

Nhn 1,37 MW- Pht 340 MW

Ph ti cc tiu- Ba t my lm vic

Pht 2,73 MW- Pht 255 MW

Ch s c- Ba t my lm vic

Pht 4,5 MW- Pht 300 MW

1.3. xut cc phng n ni dy

1.3.1. C s xut cc phng n

1.3.1.1. Yu cu cung cp in

xut c cc phng n ni dy, ta cn da vo yu cu cung cp inca cc ph ti. Yu cu ny c trnh by trong mc 1.1.2.


1.3.1.2. V tr a l

Cc ph ti c phn b trn mt bng nh trong hnh 1.1.

Hnh 1.1: Bn v tr ca ngun v cc ph ti in (T l 1: 10km)

T hnh 1.1, ta c th tnh c khong cch gia ngun v cc ph ti. Kt qutnh ton c cho trong bng 1.3.

T hnh 1.1 cng nh kt qu trong bng 1.3, ta thy rng nh my c khongcch tng i gn vi tt c cc ph ti (ngoi tr ph ti 7 gn vi h thng). Mtkhc, nhn thy mt s ph ti kh gn nhau nh ph ti 3 v 4; ph ti 1, 5 v 6.Khong cch gia cc ph ti ny c cho trong bng 1.4


Bng 1.3: Khong cch t cc ngun n cc ph ti

Ngun - Ph ti Khong cch (km) Ngun - Ph ti Khong cch (km)

N - 1 80,00 HT - 1 136,01N - 2 60,00 HT - 2 50,00N - 3 53,85 HT - 3 102,96N - 4 63,25 HT - 4 143,18N - 5 44,72 HT - 5 98,49N - 6 50,00 HT - 6 145,60N - 7 117,05 HT - 7 40,00

Bng 1.4: Khong cch gia cc ph ti gn nhau

Ph ti - Ph ti Khong cch (km) Ph ti - Ph ti Khong cch (km)

1 - 5 44,72 5 - 6 501 - 6 50 3 - 4 43,23

1.3.1.3. c im ca cc cu hnh ng dy

- S hnh tia c u im l: n gin v s ni dy, b tr thit b ngin. Gia cc ph ti khng c s lin quan n nhau, do khi xy ra sc trn mt ng dy, cc ng dy cn li khng b nh hng. Mt khc,so vi s lin thng, s ny c tn tht thp hn. Tuy nhin, s hnhtia c nhc im l mt nhiu thi gian v chi ph kho st, thit k v thicng.

- S lin thng c u im l thi gian kho st, thit k c rt ngn sovi s hnh tia. Tuy vy n c nhc im l cn c thm trm trung gian,thit b b tr i hi bo v rle, thit b t ng ho phc tp hn, tin cycung 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 linhhot, tn tht ch bnh thng thp. Tuy nhin nhc im ca mng knl b tr bo v rle v t ng ho phc tp, khi xy ra s c tn tht trnli cao, nht l ngun c chiu di dy cp in ln.


1.3.2. xut cc phng n ni dy

Trn c s phn tch nhng c im ca ngun cung cp v ph ti cng nhv tr ca chng trn s , tc gi xut mt s phng n ni dy nh sau:

1.3.2.1. Phng n 1

Hnh 1.2: S mch in phng n 1

Nhn xt:

- u im:

+ Phng n ny ch gm cc ng dy hnh tia nn m bo tin cycung cp in cho cc ph ti

+ Khi xy ra s c trn mt ng dy, cc ng dy cn li khng bnh hng trc tip

+ n gin trong vn hnh, bo v rle


- Nhc im:

+ Khong cch dn in t ngun ti ph ti 1 v 4 tng i xa nn tntht trn ng dy ln

+ Vic kho st, thi cng gp nhiu kh khn do din tch tri rng

1.3.2.2. Phng n 2


Nhn xt:

- u im:

+ Phng n ny bao gm cc ng dy hnh tia v lin thng, m bocung cp in cho tt c cc ph ti

+ Thi gian kho st, thit k c rt ngn cn cng tc thi cng cthun tin


- Nhc im:

+ Kh nng pht sinh s c mt in ca s l tng i ln v s c on ng ny c th nh hng trc tip n on ng kia

+ i vi ng dy lin thng, phi c s phi hp bo v rle

+ on ng dy t ngun ti ph ti 1 ln nn tn tht trn ng dycao

1.3.2.3. Phng n 3


Nhn xt:

- u im:

+ S bao gm cc ng dy hnh tia v lin thng, m bo cung cpin mt cch lin tc cho cc ph ti


+ Thi gian kho st, thit k c rt ngn , thi cng c thun tin

- Nhc im:



+ Tn tht in p trn ng dy tng i ln khi xy ra s c

1.3.2.4. Phng n 4


Nhn xt:

- u im:

+ S bao gm cc ng dy hnh tia v lin thng, m bo cung cpin cho tt c cc ph ti


+ Thi gian kho st, thit k c rt ngn , thi cng c thun tin dodin tch ng dy c thu hp

- Nhc im:




1.3.2.5. Phng n 5


Nhn xt:

- u im:




- Nhc im:

+ Khong cch t ngun ti ph ti 4 tng i xa nn tn tht trn ngdy tng i ln



1.3.2.6. Phng n 6


Nhn xt:


- u im:



- Nhc im:




1.3.2.7. Phng n 7


Nhn xt:


- u im:

+ Phng n bao gm cc ng dy hnh tia v lin thng v mch vng,m bo tin cy cung cp in cho cc ph ti

+ Kh nng vn hnh li linh hot

+ Tn tht ch bnh thng thp

- Nhc im:

+ Tn tht in p tng i ln khi xy ra s c trn ng dy

+ Vic b tr bo v rle v cc thit b t ng ho tng i phc tp

Trn c s nhng nh gi v phn tch trn, ta chn cc phng n 1, 2, 3, 4v 5 tin hnh tnh ton cc ch tiu k thut.

1.4. Kt lun chng 1

Trong chng 1, tc gi tin hnh phn tch ngun cung cp in ch vn hnh ca mng in. ng thi, tnh ton lng cng sut m ph ti yu cutrong ch cc i cng nh cc tiu.

Tc gi cng tin hnh cn bng cng sut tc dng v cng sut phn khngtrong mng in cc ch vn hnh khc nhau.

Ngoi ra, tc gi xut cc phng n ni dy trong mng in, tin hnhphn tch s b cc phng n v gi li cc phng n 1, 2, 3, 4 v 5 tinhnh tnh ton cc ch tiu k thut. Cc tnh ton chi tit c trnh by chngsau.


Chng 2

TNH TON CC CH TIUK THUT

2.1. Cc ch tiu k thut

2.1.1. Chn in p nh mc ca mng in

in p nh mc ca mng in nh hng ch yu n cc ch tiu kinh t -k thut, cng nh cc c trng k thut ca mng in. Mng in c in p nhmc ln th tn tht cng sut v tn tht in nng gim, tc l gim chi ph vnhnh, gim tit din dy dn v chi ph v kim loi khi xy dng mng in, ngthi tng cng sut gii hn truyn ti trn ng dy nhng vn u t xy dngmng in ln. Ngc li, mng in c in p nh mc nh, yu cu v cch inkhng cao do vn u t thp nhng chi ph vn hnh cao do tn tht cng sutv in nng ln, ngoi ra kh nng truyn ti nh. V vy, chn ng in p nhmc ca mng in khi thit k cng l mt bi ton kinh t - k thut.

in p nh mc ca mng in ph thuc vo nhiu yu t: cng sut ca phti, khong cch gia cc ph ti v cc ngun cung cp in, v tr tng i giacc ph ti vi nhau, s mng in, . . .

in p nh mc ca mng in thit k c chn ng thi vi s cungcp in. in p nh mc s b ca mng in thit k c th xc nh theo gitr ca cng sut trn mi ng dy trong mng in.

C th tnh in p nh mc ca ng dy theo cng thc kinh nghim Still

20

nh sau:

Ui = 4, 34`i +

16.Pin

(2.1)

trong :

- Ui - in p tnh ton trn on ng dy i (kV)

- `i - khong cch truyn ti on ng dy i (km)

- Pi - cng sut truyn ti trn ng dy on ng dy i (MW)

- n - s l ca ng dy i

2.1.2. La chn tit din dy dn

Cc mng in v ng dy truyn ti in p t 110kV tr ln c thc hinch yu bng cc ng dy trn khng v thng s dng dy nhm li thp (AC),ng thi cc dy dn thng c t trn cc ct b tng ly tm hay ct thp tytheo dng a hnh ng dy chy qua v in p nh mc ca mng in. Khongcch trung bnh hnh hc gia dy dn cc pha bng 4m (Dtb = 4m) i vi ngdy 110kV v 6m (Dtb = 6m) i vi ng dy 220kV.

i vi cc mng in khu vc, tit din dy dn c chn theo mt kinh tca dng in, ngha l:

Ftt =ImaxJkt

(2.2)

trong :

- Ftt - tit din dy dn tnh ton (mm2)

- Imax - dng in chy trn dy dn trong ch ph ti cc i (A)

- Jkt - mt kinh t ca dng in (A/mm2).Vi dy AC v Tmax = 5000h th Jkt = 1, 1A/mm2.

Dng in chy trn ng dy trong ch ph ti cc i c xc nh theocng thc:

Imax =Smax

n

3Um.103 (A) (2.3)

trong :

- Sm - cng sut chy trn ng dy khi ph ti cc i (MVA)


- n - s mch ca ng dy

- Um - in p nh mc ca mng in (kV)

Da vo tit din tnh c theo cng thc 2.2, tin hnh chn tit din tiuchun gn nht v kim tra cc iu kin v tn tht vng quang, bn c cang dy v pht nng dy dn trong cc ch lm vic bnh thng cng nhs c.

Vng quang s khng xut hin nu tit din dy dn F 70mm2 i ving dy 110kV v F 240mm2 i vi ng dy 220kV.

bn c ca ng dy trn khng thng c phi hp vi iu kin vvng quang ca dy dn, cho nn khng cn kim tra iu kin ny.

Trong cc ch sau s c, dng in chy trn cc dy dn ca ng dy cth vt ng k dng in lm vic trong ch bnh thng. Trng hp nh thc th xy ra trn ng dy hai mch, khi mt mch ngng cung cp in hoc cth xy ra trn ng dy c hai ngun cung cp, khi mt trong hai ngun ngngcung cp in. Trong trng hp nh vy, tit din dy dn c chn phi tha mncc iu kin pht nng cho php khi c dng in ca ch s c chy qua. iukin kim tra v dng in ti lu di cho php theo pht nng nh sau:

Ilv k1.k2.Icp (2.4)trong :

- Ilv - dng in chy trn ng dy, c th ch lm vic bnh thngcng nh ch s c

- Icp - dng in lm vic lu di cho php ca dy dn

- k1 - h s hiu chnh theo nhit

k1 =

70 xq70 ch =

70 3570 25 = 0, 88

- k2 - h s hiu chnh theo hiu ng gn, ly k2 = 1

Sau khi chn tit din tiu chun ca cc ng dy, xc nh cc thng s nv ca ng dy r0, x0, b0 v tin hnh tnh cc thng s tp trung R, X v B/2trong s thay th hnh ca cc ng dy theo cng thc:

R = 1n.r0.` ;X =

1n.x0.` ;

B

2 =12 .n.b0.` (2.5)

trong n l s mch ca ng dy.


2.1.3. Tnh tn tht in p, tn tht cng sut

2.1.3.1. Tn tht in p

in nng cung cp cho cc h tiu th c c trng bng tn s ca dngin v lch in p so vi in p nh mc trn cc cc ca thit b dng in.V h thng c cng sut v cng ln nn ta khng cn xt n nhng vn duy trtn s. Do , khi chn s b cc phng n, c th nh gi cht lng in nngtheo cc gi tr ca tn tht in p.

Tn tht in p trn ng dy i c tnh theo cng thc gn ng sau:

Ui =Pmax iRi +Qmax iXi

Um(2.6)

trong :

- Pmax i, Qmax i - cng sut tc dng v phn khng ng dy i khi ph ticc i

- Ri, Xi - in tr v in khng ca ng dy i

Tn tht in p phn trm trn ng dy i c tnh theo cng thc:

Ui =Pmax iRi +Qmax iXi

U2m.100 (2.7)

i vi ng dy c hai mch, nu ngng mt mch th tn tht in p phntrm trn ng dy bng:

Ui sc% = 2Ui bt%

Trong nhng mng in n gin, c th chp nhn c nu trong ch phti cc i tn tht in p ln nht ca mng in khng vt qu 10 15%, cntrong ch s c tn tht in p ln nht khng vt qu 15 20%. Ngha l:

Umax bt% = (10 15%)UmUmax sc% = (15 20%)Um

Trong nhng mng in phc tp (mng in kn), c th chp nhn tn thtin p ln nht n 1520% trong ch ph ti cc i khi lm vic bnh thngv 20 25% trong ch s c. Ngha l:

Umax bt% = (15 20%)UmUmax sc% = (20 25%)Um


2.1.3.2. Tnh tn tht cng sut

Tn tht cng sut trn ng dy i c tnh theo cng thc:

Si =P 2i +Q2iU2m

.(Ri + jXi) (2.8)

trong :

- Pi, Qi - cng sut tc dng v phn khng chy trn ng dy i trong ch ph ti cc i (MW, MVAr)

- Ri, Xi - in tr v in khng ca ng dy i ()

- Um - in p nh mc ca mng in (kV)

Tn tht cng sut tc dng do in tr ng dy gy ra v c tnh theo cngthc:

Pi =P 2i +Q2iU2m

.Ri (2.9)

trong : Pi, Qi, Um, Ri c nh ngha ging nh trong cng thc 2.8.

2.2. Tnh ton cho phng n 1

S mng in phng n 1 c cho trn hnh 2.1.


Tnh in p nh mc trn ng dy N - 2 - HT:Cng sut tc dng chy trn ng dy N - 2 c xc nh nh sau:

PN2 = PNMD Ptd PN PNtrong :

- PNMD - tng cng sut pht ca nh my in ch ph ti cc i

- Ptd - cng sut t dng ca nh my

- PN - tng cng sut ca cc ph ti ni vi nh my

- PN - tn tht cng sut trn cc ng dy do nh my in cung cp(PN = 5%PN )



Theo kt qu tnh c trong mc 1.2.3.1 ta c:

PNMD = 340MW ;Ptd = 34, 13MW

T s mng in hnh 2.1 d dng thy rng:

PN = P1 + P3 + P4 + P5 + P6 = 20 + 25 + 25 + 30 + 30 = 130MWPN = 5%PN = 0, 05.130 = 6, 5MW

Do :

PN2 = PNMD Ptd PN PN = 340 34, 13 130 6, 5 = 169, 37MW

Cng sut phn khng chy trn ng dy N - 2 c th c tnh gn ngnh sau:

QN2 = PN2.tg2 = 169, 37.

1 0, 920, 9 = 82, 03MV ar

Vy, dng cng sut chy trn ng dy N - 2 c gi tr:

SN2 = PN2 + jQN2 = 169, 37 + j82, 03MVA


Dng cng sut chy trn ng dy 2 - HT bng:

S2H = SN2 S2 = (169, 37 + j82, 03) (40 + j19, 37)= 129, 37 + j62, 66MVA

p dng cng thc 2.1, ta c:

- in p tnh ton trn on ng dy N - 2 bng:

UN2 = 4, 34`+ 16.P

n= 4, 34

60 + 16.169, 372 = 163, 25kV

- in p tnh ton trn on ng dy 2 - HT c gi tr:

U2H = 4, 34`+ 16.P

n= 4, 34

50 + 16.129, 372 = 142, 95kV


UN1 = 4, 34`+ 16.P

n= 4, 34

80 + 16.20 = 86, 80kV

in p ca cc on ng dy cn li c tnh tng t nh cc ng dytrn.

Kt qu tnh in p nh mc ca cc ng dy trong phng n 1 c chotrong bng 2.1.

Bng 2.1: in p tnh ton v in p nh mc ca mng in phng n 1

ng Cng sut truyn Chiu di in p tnh in p nh mcdy ti (MVA) (km) ton (kV) ca mng (kV)

N - 2 169,37 + j82,03 60 163,252 - HT 129,37 + j62,66 50 142,95 220HT - 7 120 + j58,12 40 137,24

N - 1 20 + j9,69 80 86,80

110N - 3 25 + j12,11 53,85 69,15N - 4 25 + j12,11 63,25 93,41N - 5 30 + j14,53 44,72 73,23N - 6 30 + j14,53 50 73,91



Theo ti thit k, nh my lin kt vi h thng c in p 220kV bng ngdy kp 2AC - 240 (Icp = 610 A) nn khng cn chn tit din dy dn cho ngdy ny.

Ta thy rng, ng dy s dng dy AC - 240 tha mn iu kin v tn thtvng quang cng nh bn c hc. V vy, ch cn kim tra iu kin pht nngkhi xy ra s c.

Kim tra iu kin pht nng khi xy ra s c trn ng dy N - 2 - HT:on ng dy N - 2:Khi ngng mt mch trn ng dy, dng in chy trn on N - 2 bng:

IN2 sc =Smax3Um

.103 =

169, 372 + 82, 0323.220

.103 = 493, 87A

V IN2 sc = 493, 87 < k1.k2.Icp = 0, 88.610 = 536, 8A nn dy dn chntha mn iu kin pht nng cho php.

on ng dy 2 - HT:Dng in chy trn ng dy 2 - HT khi xy ra s c mt mch c gi tr:

I2H sc =Smax3Um

.103 =

129, 372 + 62, 6623.220

.103 = 377, 24A

V I2H sc = 377, 24 < k1.k2.Icp = 0, 88.610 = 536, 8A nn dy dn chntha mn iu kin pht nng cho php.

Tnh tit din ca ng dy N - 1:Dng in chy trn ng dy N - 1 bng:

IN1 =SN1

n

3Um=

202 + 9, 6923.110

.103 = 116, 64A

Tit din tnh ton c gi tr:

Ftt =IN1Jkt

= 116, 641, 1 = 106, 03mm2

Vy ta chn dy AC - 95 c Icp = 330A


V ph ti 1 l h tiu th loi III c cung cp bi ng dy mt mch nnkhng xt n iu kin pht nng khi xy ra s c.

Tnh tit din ca ng dy N - 3:Dng in chy trn ng dy N - 3 bng:

IN3 =SN3

n

3Um=

252 + 12, 1122.

3.110.103 = 72, 90A

Tit din tnh ton c gi tr:

Ftt =IN3Jkt

= 72, 901, 1 = 66, 27mm2

Vy ta chn dy AC - 70 c Icp = 265AKhi ngng mt mch ca ng dy, mch cn li phi truyn ti lng cng

sut gp i v dng in chy trn mch bng:

IN3 sc = 2.IN3 = 2.72, 90 = 145, 8A

V IN3 sc = 145, 8 < k1.k2.Icp = 0, 88.265 = 233, 2A nn tit din chntha mn iu kin pht nng cho php.

Tnh ton cc ng dy cn li tng t nh i vi ng dy trn. Kt quc tng hp trong bng 2.2.

Bng 2.2: Tit din tiu chun ca cc ng dy trong phng n 1

ng S S Ibt Ftt Ftc Icp Isc k1.k2.Icpdy l (MVA) (A) (mm2) (mm2) (A) (A) (A)

N - 2 2 169,37+j82,03 246,93 224,49 240 610 493,87 536,802 - HT 2 129,37 + j62,66 188,62 171,47 240 610 377,23 536,80HT - 7 2 120 + j58,12 174,95 159,05 240 610 349,91 536,80N - 1 1 20 + j9,69 116,64 106,03 95 330 0 290,40N - 3 2 25 + j12,11 72,90 66,27 70 265 145,80 233,20N - 4 1 25 + j12,11 145,80 132,54 120 380 0 334,40N - 5 2 30 + j14,53 87,48 79,52 70 265 174,95 233,20N - 6 2 30 + j14,53 87,48 79,52 70 265 174,95 233,20

Sau khi tm c tit din dy dn tiu chun, tin hnh tnh cc thng s tptrung R, X, B/2 ca ng dy theo cng thc 2.5.

Kt qu tnh cc thng s ca tt c cc ng dy trong mng c cho trongbng 2.3.


Bng 2.3: Thng s cc ng dy phng n 1

ng Loi ` r0 x0 b0.106 R XB2 .10

4

dy dy (km) (/km) (/km) (S/km) () () (S)N - 2 AC - 240 60 0,13 0,401 2,74 3,90 12,03 1,642 - HT AC - 240 50 0,13 0,401 2,74 3,25 10,03 1,37HT - 7 AC - 240 40 0,13 0,401 2,74 2,60 8,02 1,10N - 1 AC - 95 80 0,33 0,414 2,75 26,40 33,12 1,10N - 3 AC - 70 53,85 0,46 0,425 2,68 12,39 11,44 1,44N - 4 AC - 120 63,25 0,27 0,408 2,79 17,08 25,80 0,88N - 5 AC - 70 44,72 0,46 0,425 2,68 10,29 9,50 1,20N - 6 AC - 70 50 0,46 0,425 2,68 11,50 10,63 1,34


2.2.3.1. Tn tht in p

p dng cng thc 2.7, ta c:Tn tht in p phn trm trn ng dy N - 1 bng:

UN1% =PN1RN1 +QN1XN1

U2m.100 = 20.26, 4 + 9, 69.33, 121102 .100 = 7, 01%

V ph ti 1 l h tiu th loi III, c cung cp bng ng dy n nn khing dy s c, ph ti b ngng cung cp in. Do , khng tnh tn tht in pphn trm ch s c i vi cc h tiu th loi ny.

Tn tht in p phn trm trn ng dy N - 5 ch lm vic bnh thngc gi tr:

UN5 bt% =PN5RN5 +QN5XN5

U2m.100 = 30.10, 29 + 14, 53.9, 51102 .100 = 3, 69%

Khi xy ra s c ngng mt mch th tn tht in p phn trm trn ng dyN - 5 bng:

UN5 sc% = 2.UN5 bt% = 2.3, 69 = 7, 38%

Tnh tn tht in p phn trm trn cc ng dy cn li tng t nh ngdy trn, kt qu tnh ton c cho trong bng 2.4.


2.2.3.2. Tnh tn tht cng sut

p dng cng thc 2.9, ta c:Tn tht cng sut trn ng dy N - 1 bng:

PN1 =P 2N1 +Q2N1

U2m.RN1 =

202 + 9, 6921102 .26, 4 = 1, 08MW

Tin hnh tnh tn tht cng sut cho cc on ng dy cn li, kt qu tnhton c cho trong bng 2.4.

Bng 2.4: Tn tht in p phn trm, tn tht cng sut phng n 1

ng dy Ubt% Usc% P(MW)N - 2 3,40 6,81 2,852 - HT 2,17 4,33 1,39HT - 7 1,61 3,22 0,96N - 1 7,01 0 1,08N - 3 3,70 7,41 0,79N - 4 6,11 0 1,09N - 5 3,69 7,38 0,94N - 6 4,13 8,25 1,06

Tng 10,15

T kt qu trong bng 2.4, ta c:

- Tn tht in p phn trm ln nht ch vn hnh bnh thng phngn 1 bng:

Umax bt% = UN1 bt% = 7, 01%

- Tn tht in p phn trm ln nht trong ch s c phng n 1 c gi tr:

Umax sc% = UN6 sc% = 8, 25%

- Tng tht cng sut tc dng trong phng n 1 bng:

P = 10, 15MW






Dng cng sut chy trn on ng dy N - 3 c gi tr:

SN3 = S3 + S4 = (25 + j12, 11) + (25 + j12, 11) = 50 + j24, 22MVA

Dng cng sut chy trn ng dy 3 - 4 bng:

S34 = S4 = 25 + j12, 11MVA



UN3 = 4, 34`+ 16.P

n= 4, 34

53, 85 + 16.502 = 92, 46kV

- in p tnh ton trn on ng dy 3 - 4 c gi tr:

U34 = 4, 34`+ 16.P

n= 4, 34

41, 23 + 16.25 = 91, 16kV

Kt qu tnh in p trn cc on ng dy v chn in p nh mc chomng in c th hin trong bng 2.5.




N - 2 169,37 + j82,03 60 163,252 - HT 129,37 + j62,66 50 142,95 220HT - 7 120 + j58,12 40 137,24

N - 1 20 + j9,69 80 86,80

110N - 3 50 + j24,22 53,85 92,463 - 4 25 + j12,11 41,23 91,16N - 5 30 + j14,53 44,72 73,23N - 6 30 + j14,53 50 73,91


Kt qu chn tit din dy dn v tnh thng s cho cc ng dy c tnghp trong bng 2.6 v 2.7.



N - 2 2 169,37 + j82,03 246,93 224,49 240 610 493,87 536,802 - HT 2 129,37 + j62,66 188,62 171,47 240 610 377,23 536,80HT - 7 2 120 + j58,12 174,95 159,05 240 610 349,91 536,80N - 1 1 20 + j9,69 116,64 106,03 95 330 0 290,40N - 3 2 50 + j24,22 145,80 132,54 120 380 291,59 334,403 - 4 1 25 + j12,11 145,80 132,54 120 380 0 334,40N - 5 2 30 + j14,53 87,48 79,52 70 265 174,95 233,20N - 6 2 30 + j14,53 87,48 79,52 70 265 174,95 233,20


Tnh tn tht in p trn ng dy N - 3 - 4

- Trong ch lm vic bnh thng:



ng Loi ` r0 x0 b0.106 R XB2 .10

4

dy dy (km) (/km) (/km) (S/km) () () (S)N - 2 AC - 240 60 0,13 0,401 2,74 3,90 12,03 1,642 - HT AC - 240 50 0,13 0,401 2,74 3,25 10,03 1,37HT - 7 AC - 240 40 0,13 0,401 2,74 2,60 8,02 1,10N - 1 AC - 95 80 0,33 0,414 2,75 26,40 33,12 1,10N - 3 AC - 120 53,85 0,27 0,408 2,79 7,27 10,99 1,503 - 4 AC - 120 41,23 0,27 0,408 2,79 11,13 16,82 0,58N - 5 AC - 70 44,72 0,46 0,425 2,68 10,29 9,50 1,20N - 6 AC - 70 50 0,46 0,425 2,68 11,50 10,63 1,34

Tn tht in p phn trm trn ng dy N - 3 c gi tr:

UN3 bt% =PN3RN3 +QN3XN3

U2m.100 = 50.7, 27 + 24, 22.10, 991102 .100 = 5, 20%

Tn tht in p phn trm trn ng dy 3 - 4 bng:

U34 bt% =P34R34 +Q34X34

U2m.100 = 25.11, 13 + 12, 11.16, 821102 .100 = 3, 98%

Nh vy, tn tht in p phn trm trn ng dy N - 3 - 4 ch lm vicbnh thng c gi tr:

UN34 bt% = UN3 bt% + U34 bt% = 5, 20 + 3, 98 = 9, 18%

- Trong ch s c:

i vi ng dy N - 3 - 4, s c xy ra nng n nht l ngng lm vic mtmch trn ng dy N - 3, tn tht in p phn trm trn ng dy c gi tr:

UN3 sc% = 2.UN3 bt = 2.5, 20 = 10, 40%

V vy, tn tht in p phn trm trong ch s c i vi ng dy N - 3- 4 bng:

UN34 sc% = UN3 sc% + U34 bt% = 10, 40 + 3, 98 = 14, 38%

Tn tht in p, tn tht cng sut c tnh ton tng t nh phng n 1.Kt qu c tng hp trong bng 2.8.




ng dy Ubt% Usc% P(MW)N - 2 3,40 6,81 2,852 - HT 2,17 4,33 1,39HT - 7 1,61 3,22 0,96N - 1 7,01 0 1,08N - 3 5,20 10,41 1,853 - 4 3,98 0 0,71N - 5 3,69 7,38 0,94N - 6 4,13 8,25 1,06

Tng 10,84


Umax bt% = UN34 bt% = UN3 bt% + U34 bt%= 5, 20 + 3, 98 = 9, 18%


Umax sc% = UN34 sc% = UN3 sc% + U34 bt%= 10, 41 + 3, 98 = 14, 39%

- Tng tht cng sut tc dng trong phng n 2 bng: P = 10, 84MW




Kt qu tnh in p trn cc on ng dy v chn in p nh mc chomng in cho trong bng 2.9.





N - 2 169,37 + j82,03 60 163,252 - HT 129,37 + j62,66 50 142,95 220HT - 7 120 + j58,12 40 137,24

N - 3 25 + j12,11 53,85 69,15

110N - 4 25 + j12,11 63,25 93,41N - 5 50 + j24,22 44,72 91,525 - 1 20 + j9,69 44,72 82,88N - 6 30 + j14,53 50 73,91






N - 2 2 169,37 + j82,03 246,93 224,49 240 610 493,87 536,802 - HT 2 129,37 + j62,66 188,62 171,47 240 610 377,23 536,80HT - 7 2 120 + j58,12 174,95 159,05 240 610 349,91 536,80N - 3 2 25 + j12,11 72,90 66,27 70 265 145,80 233,20N - 4 1 25 + j12,11 145,80 132,54 120 380 0 334,40N - 5 2 50 + j24,22 145,80 132,54 120 380 291,59 334,405 - 1 1 20 + j9,69 116,64 106,03 95 330 0 290,40N - 6 2 30 + j14,53 87,48 79,52 70 265 174,95 233,20


ng Loi ` r0 x0 b0.106 R XB2 .10

4

dy dy (km) (/km) (/km) (S/km) () () (S)N - 2 AC - 240 60 0,13 0,401 2,74 3,90 12,03 1,642 - HT AC - 240 50 0,13 0,401 2,74 3,25 10,03 1,37HT - 7 AC - 240 40 0,13 0,401 2,74 2,60 8,02 1,10N - 3 AC - 70 53,85 0,46 0,425 2,68 12,39 11,44 1,44N - 4 AC - 120 63,25 0,27 0,408 2,79 17,08 25,80 0,88N - 5 AC - 120 44,72 0,27 0,408 2,79 6,04 9,12 1,255 - 1 AC - 95 44,72 0,33 0,414 2,75 14,76 18,51 0,61N - 6 AC - 70 50 0,46 0,425 2,68 11,50 10,63 1,34






ng dy Ubt% Usc% P(MW)N - 2 3,40 6,81 2,852 - HT 2,17 4,33 1,39HT - 7 1,61 3,22 0,96N - 3 3,70 7,41 0,79N - 4 6,11 0,00 1,09N - 5 4,32 8,64 1,545 - 1 3,92 0,00 0,60N - 6 4,13 8,25 1,06

Tng 10,27





- Tng tht cng sut tc dng trong phng n 3 bng: P = 10, 27MW









N - 2 169,37 + j82,03 60 163,252 - HT 129,37 + j62,66 50 142,95 220HT - 7 120 + j58,12 40 137,24

N - 3 50 + j24,22 53,85 92,46

1103 - 4 25 + j12,11 41,23 91,16N - 5 50 + j24,22 44,72 91,525 - 1 20 + j9,69 44,72 82,88N - 6 30 + j14,53 50 73,91






N - 2 2 169,37 + j82,03 246,93 224,49 240 610 493,87 536,802 - HT 2 129,37 + j62,66 188,62 171,47 240 610 377,23 536,80HT - 7 2 120 + j58,12 174,95 159,05 240 610 349,91 536,80N - 3 2 50 + j24,22 145,80 132,54 120 380 291,59 334,403 - 4 1 25 + j12,11 145,80 132,54 120 380 0 334,40N - 5 2 50 + j24,22 145,80 132,54 120 380 291,59 334,405 - 1 1 20 + j9,69 116,64 106,03 95 330 0 290,40N - 6 2 30 + j14,53 87,48 79,52 70 265 174,95 233,20


ng Loi ` r0 x0 b0.106 R XB2 .10

4

dy dy (km) (/km) (/km) (S/km) () () (S)N - 2 AC - 240 60 0,13 0,401 2,74 3,90 12,03 1,642 - HT AC - 240 50 0,13 0,401 2,74 3,25 10,03 1,37HT - 7 AC - 240 40 0,13 0,401 2,74 2,60 8,02 1,10N - 3 AC - 120 53,85 0,27 0,408 2,79 7,27 10,99 1,503 - 4 AC - 120 41,23 0,27 0,408 2,79 11,13 16,82 0,58N - 5 AC - 120 44,72 0,27 0,408 2,79 6,04 9,12 1,255 - 1 AC - 95 44,72 0,33 0,414 2,75 14,76 18,51 0,61N - 6 AC - 70 50 0,46 0,425 2,68 11,50 10,63 1,34






ng dy Ubt% Usc% P(MW)N - 2 3,40 6,81 2,852 - HT 2,17 4,33 1,39HT - 7 1,61 3,22 0,96N - 3 5,20 10,41 1,853 - 4 3,98 0,00 0,71N - 5 4,32 8,64 1,545 - 1 3,92 0,00 0,60N - 6 4,13 8,25 1,06

Tng 10,96






P = 10, 96MW









N - 2 169,37 + j82,03 60 163,252 - HT 129,37 + j62,66 50 142,95 220HT - 7 120 + j58,12 40 137,24

N - 3 25 + j12,11 53,85 69,15

110N - 4 25 + j12,11 63,25 93,41N - 5 30 + j14,53 44,72 73,23N - 6 50 + j24,22 50 92,076 - 1 20 + j9,69 50 83,48






N - 2 2 169,37 + j82,03 246,93 224,49 240 610 493,87 536,802 - HT 2 129,37 + j62,66 188,62 171,47 240 610 377,23 536,80HT - 7 2 120 + j58,12 174,95 159,05 240 610 349,91 536,80N - 3 2 25 + j12,11 72,90 66,27 70 265 145,80 233,20N - 4 1 25 + j12,11 145,80 132,54 120 380 0 334,40N - 5 2 30 + j14,53 87,48 79,52 70 265 174,95 233,20N - 6 2 50 + j24,22 145,80 132,54 120 380 291,59 334,406 - 1 1 20 + j9,69 116,64 106,03 95 330 0 290,40


ng Loi ` r0 x0 b0.106 R XB2 .10

4

dy dy (km) (/km) (/km) (S/km) () () (S)N - 2 AC - 240 60 0,13 0,401 2,74 3,90 12,03 1,642 - HT AC - 240 50 0,13 0,401 2,74 3,25 10,03 1,37HT - 7 AC - 240 40 0,13 0,401 2,74 2,60 8,02 1,10N - 3 AC - 70 53,85 0,46 0,425 2,68 12,39 11,44 1,44N - 4 AC - 120 63,25 0,27 0,408 2,79 17,08 25,80 0,88N - 5 AC - 70 44,72 0,46 0,425 2,68 10,29 9,50 1,20N - 6 AC - 120 50 0,27 0,408 2,79 6,75 10,20 1,406 - 1 AC - 95 50 0,33 0,414 2,75 16,50 20,70 0,69






ng dy Ubt% Usc% P(MW)N - 2 3,40 6,81 2,852 - HT 2,17 4,33 1,39HT - 7 1,61 3,22 0,96N - 3 3,70 7,41 0,79N - 4 6,11 0 1,09N - 5 3,69 7,38 0,94N - 6 4,83 9,66 1,726 - 1 4,38 0 0,67

Tng 10,41






P = 10, 41MW

2.7. So snh cc ch tiu k thut

thun tin khi so snh cc phng n v mt k thut, cc gi tr tn tht inp phn trm cng nh tng tn tht cng sut ca cc phng n c tng hp bng 2.21.

T kt qu tnh ton bng 2.21, ta chn ba phng n 1, 3 v 4 tin hnh sosnh kinh t.


Bng 2.21: So snh ch tiu k thut cc phng n

Phng n1 2 3 4 5

Umax bt% 7,01 9,18 8,24 9,18 9,21Umax sc% 8,25 14,39 12,56 14,39 14,04P (MW) 10,15 10,84 10,27 10,96 10,41

2.8. Kt lun chng 2

Trong chng 2, tc gi tin hnh la chn in p nh mc ca mng in,tit din dy dn trong tng phng n. ng thi tnh cc thng s tp trung R, Xv B/2 ca cc on ng dy.

Ngoi ra, tc gi cn tnh tn tht in p, tn tht cng sut ca tng phngn, so snh chng vi nhau v chn ba phng n 1, 3 v 4 tin hnh so snh kinht.


Chng 3

SO SNH KINH T VCHN PHNG N TI U

Khi tnh ton, thit k mng li in cn phi m bo yu cu v kinh t v kthut. Mc d trn thc t hai yu cu kinh t v k thut thng mu thun nhau,mt li in c ch tiu k thut tt, vn u t v chi ph vn hnh cao.

Ngc li, li in c vn u t, chi ph vn hnh nh th tn tht cao, cutrc li in phc tp, vn hnh km linh hot, an ton thp. V vy vic nhgi tnh ton ch tiu kinh t, k thut ca mt li in s m bo cho vic t chtiu v k thut, hp l v kinh t.

3.1. Ch tiu kinh t

n gin so snh cc phng n, c th tin hnh ch i vi nhng phn tkhc nhau ca s mng in. Nhng phn t chung ca cc s c th khngcn so snh.

V pha in p 220 kV ca cc phng n so snh l ging nhau nn ta khngcn tnh kinh k i vi cc mch ny.

3.1.1. Vn u t xy dng mng in

Tng vn u t ca mi phng n c xc nh theo cng thc:

K = Kd +Kt

45

trong :

- Kd - tng vn u t v xy dng ng dy (VN)

- Kt - tng vn u t v cc trm bin p (VN)

V cc phng n c cng in p nh mc do n gin khng cn tnhgi thnh ca cc my bin p trong cc trm h p. Do , tng vn u t ca miphng n so snh c xc nh theo cng thc:

K = Kd = Ki

trong :

- Kd - tng vn u t xy dng ng dy ca mng in (VN)

- Ki - vn u t cho ng dy th i (VN)

Ki = k0i.`i.x (3.1)

trong :

+ k0i - sut u t cho 1km ng dy (/km)

+ `i - chiu di on ng dy th i (km)

+ x = 1 nu l n, x = 1, 6 nu l kp

Ta c bng gi thnh 1km ng dy trn khng mt mch in p 110kV nhsau:

Bng 3.1: Gi thnh 1km ng dy trn khng mt mch in p 110kV

Loi dy AC - 70 AC - 95 AC - 120 AC - 150 AC - 185 AC - 240

k0i.106208 283 354 403 441 500

(/km)

3.1.2. Chi ph vn hnh hng nm

Chi ph vn hnh hng nm l ch tiu kinh t - k thut quan trng ca mngin v cn thit vn hnh cc thit b cng nh mng in trong mt nm. Chiph vn hnh hng nm c hnh thnh t nhng khu hao hao mn, cc chi ph v


sa cha thng xuyn v phc v mng in, cng nh chi ph v cc tn tht innng hng nm.

Nh vy, chi ph vn hnh hng nm c tnh theo cng thc:

Y = avh.K + A.c (3.2)

trong :

- avh - h s khu hao hng nm v hao mn v phc v. Ly avh = 4%

- K - tng vn u t v xy dng ng dy trong mng in (VN)

- A - tng tn tht in nng hng nm trong mng in (kWh)

- c - gi tin tn tht in nng c = 800 /kWh

Tng tn tht in nng ca mng in trong mt nm c tnh theo cng thc:

A = Pi max.

trong :

- Pi max - tn tht cng sut trn ng dy th i khi ph ti cc i

- - thi gian tn tht cng sut cc i, c tnh theo cng thc:

= (0, 124 + Tmax.104)2.8760

trong Tmax l thi gian s dng cng sut cc i.

Nh vy, vi Tmax = 5000h th thi gian tn tht cng sut cc i bng:

= (0, 124+Tmax.104)2.8760 = (0, 124+5000.104)2.8760 = 3410, 93h

3.1.3. Chi ph tnh ton hng nm

Chi ph tnh ton hng nm Z ca mng in c tnh theo cng thc:

Z = atc.K + Y (3.3)

trong :


- atc - h s tiu chun thu hi vn u t atc =1Ttc

trong Ttc l thi gian

tiu chun thu hi vn u t. Ly Ttc = 8 nm nn ta c:

atc =1Ttc

= 18 = 0, 125

- K - tng vn u t v xy dng ng dy trong mng in

- Y - chi ph vn hnh hng nm




- Vn u t xy dng ng dy N - 1 bng:

KN1 = k0N1 .`N1.x = 283.106.80 = 22640.106 ()

- Vn u t xy dng ng dy N - 6 bng:

KN6 = k0N6 .`N6.x = 208.106.50.1, 6 = 16640.106 ()

Tin hnh tnh vn u t cho cc on ng dy cn li tng t nh trn, ktqu c cho trong bng 3.2.

Bng 3.2: Vn u t xy dng ng dy phng n 1

ng Loi ` k0 Kidy dy (km) (106/km) (106)

N - 1 AC - 95 80 283 22640N - 3 AC - 70 53,85 208 17921,83N - 4 AC - 120 63,25 354 22388,93N - 5 AC - 70 44,72 208 14883,27N - 6 AC - 70 50 208 16640

Tng 94474,02

T bng 3.2, ta thy rng tng vn u t xy dng ng dy phng n 1 bng:

K = Ki = 94474, 02.106



T bng 2.21, ta thy rng tng tn tht cng sut trn ng dy phng n 1c gi tr:

P = 10, 15MW

Nh vy, tn tht in nng hng nm trong mng in phng n 1 bng:

A = P. = 10, 15.3410, 93 = 34620, 94MWh

p dng cng thc 3.2, ta c chi ph vn hnh hng nm ca mng in phngn 1 c gi tr:

Y = avh.K+A.c = 0, 04.94474, 02.106+34620, 94.103.800 = 31475, 71.106


p dng cng thc 3.3, ta c chi ph tnh ton hng nm Z ca mng in phngn 1 bng:

Z = atc.K + Y = 0, 125.94474, 02.106 + 31475, 71.106 = 43284, 96.106

Cc ch tiu kinh t ca mng in phng n 1 c tng hp trong bng 3.3.

Bng 3.3: Ch tiu kinh t mng in phng n 1

P A K Y Z(MW) (MWh) (106 ) (106 ) (106 )10,15 34620,94 94474,02 31475,71 43284,96



Tin hnh tnh vn u t cho cc on ng dy tng t nh phng n 1,kt qu c cho trong bng 3.4.


K = Ki = 94937, 08.106




N - 3 AC - 70 53,8516 208 17921,828N - 4 AC - 120 63,25 354 22388,93N - 5 AC - 120 44,72 354 25330,185 - 1 AC - 95 44,72 283 12656,14N - 6 AC - 70 50 208 16640

Tng 94937,08



P = 10, 27MW


A = P. = 10, 27.3410, 93 = 35030, 25MWh


Y = avh.K+A.c = 0, 04.94937, 08.106+35030, 25.103.800 = 31821, 68.106



Z = atc.K + Y = 0, 125.94937, 08.106 + 31821, 68.106 = 43688, 82.106




Tin hnh tnh vn u t cho cc on ng dy tng t nh phng n 1,kt qu c cho trong bng 3.6.



P A K Y Z(MW) (MWh) (106 ) (106 ) (106 )10,27 35030,25 94937,08 31821,68 43688,82



N - 3 AC - 120 53,8516 354 30501,573 - 4 AC - 120 41,23 354 14595,79N - 5 AC - 120 44,72 354 25330,185 - 1 AC - 95 44,72 283 12656,14N - 6 AC - 70 50 208 16640

Tng 99723,69


K = Ki = 99723, 69.106



P = 10, 96MW


A = P. = 10, 96.3410, 93 = 37383, 7928MWh


Y = avh.K+A.c = 0, 04.99723, 69.106+37383, 7928.103.800 = 33895, 98.106




Z = atc.K + Y = 0, 125.99723, 69.106 + 33895, 98.106 = 46361, 44.106



P A K Y Z(MW) (MWh) (106 ) (106 ) (106 )10,96 37383,79 99723,69 33895,98 46361,44

3.5. So snh cc ch tiu kinh t, chn phng n tiu

Cc ch tiu kinh t - k thut ca c ba phng n so snh c tng hp trongbng 3.8.

Bng 3.8: Tng hp cc ch tiu kinh t - k thut ca cc phng n so snh

Phng nCc ch tiu

Umax bt Umax sc K.106 Y.106 Z.106

(%) (%) () () ()

1 7,01 8,25 94474,02 31475,71 43284,963 8,24 12,56 94937,08 31821,68 43688,824 9,18 14,39 99723,69 33895,98 46361,44

T bng 3.8, ta c th thy rng cc phng n u m bo yu cu v mt kthut. Tuy nhin, phng n 1 c chi ph tnh ton hng nm (chi ph quy i) nhnht nn s l phng n hp l nht v kinh t. V vy, ta chn phng n 1 lmphng n ti u.


3.6. Kt lun chng 3

Trong chng 3, tc gi tin hnh tnh ton vn u t xy dng mng in,chi ph vn hnh v chi ph tnh ton hng nm ca tng phng n ni in. ngthi, tc gi cng so snh kinh t - k thut ca cc phng n v chn phngn 1 l phng n ni in ti u.


Chng 4

LA CHNMY BIN P,S TRM BIN P VS NI IN

4.1. Chn s lng v cng sut my bin p

Trm bin p l mt phn t rt quan trng ca h thng in, n c nhim vtip nhn in nng t h thng, bin i t cp in p ny sang cp in p khcv phn phi cho cc mng in tng ng. V vy, vic la chn cc my bin pcn m bo tnh cht cung cp in lin tc v yu cu v kinh t, k thut.

4.1.1. Chn s lng v cng sut my bin p trong cc trmtng p ca nh my in

Nh my nhit in c s ni in nh hnh 4.1.

4.1.1.1. My bin p hai cun dy trong s b my pht - my bin p haicun dy

Nhng my bin p ny mang ti bng phng nn khng c nhu cu iu chnhin p pha h. Nh vy, ch cn iu chnh in p pha cao p v c iu chnhtrc tip bng t ng iu chnh kch t ca my pht.

54

Hnh 4.1: S ni in nh my in

iu kin chn my bin p l:

SmB SmF = PmFcos =1000, 8 = 125MVA

trong :

- n - s t my pht trong nh my

- SmF - cng sut nh mc mt t my pht

- Std - cng sut t dng ca nh my in

- PmF - cng sut pht tc dng nh mc ca mt t my

Nh vy, ta chn my bin p TDq - 125000/110 c cc thng s cho trongbng 4.1.

4.1.1.2. My bin p t ngu

i vi my bin p t ngu th li t cng nh ba cun dy ni tip, trung vh u c thit k theo cng sut tnh ton:

Stt = .SmB


Bng 4.1: Thng s ca my bin p trong s b

SmCc s liu k thut S liu tnh ton

(MVA)Um Un Pn P0 I0 R X Q0

Cao H (%) (kW) (kW) (%) () () (kVAr)125 121 10,5 10,5 520 120 0,55 0,33 11,1 678

trong - h s c li.

= UC UTUC

= 220 110220 = 0, 5

Cng sut ca my bin p t ngu c chn theo iu kin:

SmTN SmF

= PmF. cos =

1000, 5.0, 8 = 250MVA

Vy ta chn my bin p ATDqTH - 250000/220/110 c thng s c chotrong bng 4.2.

Bng 4.2: Thng s k thut ca my bin p t ngu

SmUm Un Pn P0 I0 Q0

(MVA)(kV) (%) (kW)

(kW) (%) (kVAr)C T H C-T C-H T-H C-T C-H T-H

250 230 121 15,75 11 32 20 - 520 - 145 0,5 1250

Ghi ch: Trong phm vi n li in, tc gi khng tin hnh kim tra quti my bin p.

4.1.2. Chn s lng v cng sut ca my bin p trong cctrm h p

chn c my bin p ta phi cn c vo cng sut, in p ca h thngv ca ph ti. i vi mng in thit k, cp in p ca cc h tiu th l 22kV(ngoi tr ph ti 2 v ph ti 7), cp in p ca ng dy l 110kV, ngoi ra cnc ng dy cp in p 220kV ni nh my in vi h thng in qua ph ti 2v ng dy t h thng in n ph ti 7.


V ph ti 2 v ph ti 7 c cp in p 220kV nn khng tin hnh chn mybin p cho hai trm ny.

S lng my bin p ph thuc vo tnh cht ca h tiu dng.

- i vi h tiu th loi I: yu cu cung cp in lin tc, cht lng in nngm bo nn trm bin p ca cc ph ti ny ta s dng hai my bin p bapha hai dy qun lm vic song song. Khi mt my bin p b s c th mybin p cn li vn c kh nng cung cp in cho ton b ph ti lc cc i.

Xut pht t iu kin qu ti cho php bng 40% trong thi gian ph ti cci, cng sut ca mi my trong trm c xc nh theo cng thc:

SmB Smaxkscqt

=P 2max +Q2max

kscqt(4.1)

trong :

+ Smax - cng sut ca ph ti ch cc i

+ kscqt - h s qu ti ca my bin p trong ch s c, kscqt = 1, 4

+ Pmax, Qmax - cng sut tc dng, phn khng ca ph ti ch cci

- i vi h tiu th loi III: mc yu cu cung cp in khng cao nn m bo v mt kinh t ta ch cn s dng mt my bin p ba pha hai dyqun. V vy, trng hp ny ta khng xt n qu ti my bin p.

Cng sut ca my bin p c xc nh theo cng thc:

SmB Smax =P 2max +Q2max (4.2)

+ Smax - cng sut ca ph ti ch cc i

+ Pmax, Qmax - cng sut tc dng, phn khng ca ph ti ch cci

S liu v cng sut ca cc ph ti ch cc i c ly trong bng 2.1.p dng cng thc 4.2, ta c cng sut ca my bin p trong trm 1 bng:

SmB1 P 21 max +Q21 max =

202 + 9, 692 = 22, 22MVA

Vy, ta chn my bin p TPDH - 25000/110.Tin hnh tnh ton tng t cho cc trm cn li, kt qu c cho trong bng

4.3.Thng s ca cc my bin p va chn c cho trong bng 4.4.


Bng 4.3: S lng, cng sut my bin p trong cc trm h p

TrmLoi ph Smax Stt SmB Kiu my

S lngti (MVA) (MVA) (MVA) (my)

1 III 20 + j9,69 22,22 25 TPDH - 25000/110 13 I 25 + j12,11 19,84 25 TPDH - 25000/110 24 III 25 + j12,11 27,78 32 TPDH - 32000/110 15 I 30 + j14,53 23,81 25 TPDH - 25000/110 26 I 30 + j14,53 23,81 25 TPDH - 25000/110 2

Bng 4.4: Thng s ca my bin p trong cc trm h p

Kiu mySm Um Un Pn P0 I0 R X Q0

(MVA) C H (%) (kW) (kW) (%) () () (kVAr)TPDH

25 115 22 10,5 120 29 0,8 2,54 55,9 20025000/110

TPDH32 115 22 10,5 145 35 0,75 1,87 43,5 240

32000/110

4.2. Chn s cc trm

m bo cung cp in lin tc cho cc ph ti, n gin, linh hot, thuntin trong thao tc, an ton trong vn hnh ng thi m bo tnh kinh t cho ccphng n ta phi la chn cc s thch hp.

4.2.1. S trm tng p ca nh my nhit in

S l vo ra trong nh my nhit in:

- Cp in p 220kV c s mch:

+ Mch my bin p: c 2 mch n t my bin p t ngu.

+ Mch ng dy: c 2 mch lin lc vi h thng qua ph ti 2 (mt lkp)

Vy cp in p 220kV c tng s mch l 4, ngoi ra y l trm rt quantrng do ta dng s ba my ct trn hai mch (s mt ri). S c th hin trn hnh 4.2.


- Cp in p 110kV c s mch:

+ Mch my bin p: c 4 mch (2 mch t my bin p t ngu, 2 mcht my bin p hai cun dy)

+ Mch ng dy: c 8 mch gm 3 l kp v 2 l n

Vy cp in p 110kV c tng s mch l 12, do ta dng s hai hthng thanh gp c thanh gp vng

S trm tng p ca nh my nhit in c cho trong hnh 4.2.

~

110 kV

~

220 kV

~ ~

Hnh 4.2: S trm tng p nh my in

4.2.2. S trm bin p trung gian

y l trm rt quan trng v ngoi nhim v cung cp in cho ph ti 2 n cnlm nhim v lin lc gia nh my in v h thng. Do vy ta chn s hai hthng thanh gp cho trm ny.

S ni in ca trm trung gian c cho trong hnh 4.3.


Hnh 4.3: S ni in trm trung gian

4.2.3. S trm bin p gim p

4.2.3.1. Ph ti loi I:

m bo cung cp in mt cch lin tc cho ph ti loi I, ta s dng s cu. S ny c t my ct hn s mch nhng tin cy cung cp in vn cao,c s dng ti cc trm c hai ng dy v hai my bin p, thc cht l hai bng dy - my bin p c lin h vi nhau bng cu ni dng my ct in.

Trong s cu my ct c th nm pha ng dy hoc my bin p, tythuc vo v tr my ct m ta c hai loi s cu: s cu trong v s cungoi.

- S cu ngoi: my ct cu pha ng dy, my ct mch pha my binp.

Trong s ny, v pha ng dy khng c my ct m ch c dao cch ly.Khi sa cha hay s c mt my bin p, hai ng dy vn lm vic bnhthng. Ngc li, khi s c mt ng dy th mt my bin p b mt intm thi. S ny thch hp vi ng dy ngn, xc sut s c t, cc trm


bin p c ph ti bin ng ln, thng xuyn ng ct my bin p trongvn hnh.

- S cu trong: my ct cu pha my bin p, my ct mch pha ng dy.

Trong s ny, my ct nm pha ng dy, pha cao p ca my binp khng t my ct. Vi s ny, u nhc im hon ton ngc li sovi s cu ngoi v n thch hp vi cc trm bin p t

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