Tiiu ban: Mdi tru&ng vd Ndng lugng ISBN: 978-604-913-013-7<br />
<br />
<br />
XAC DINH VI TRI TOI ifV DAT NGUON PHAN TAN TRONG h\f6l<br />
DlfiN BANG PHlTONG PHAP SLT DUNG HE SO TON THAT<br />
<br />
Le Cong Thinh<br />
Vien Khoa hgc nang lugng<br />
Nha A9, sd 18 - Hoang Quoc Viet, Ciu Giiy, Ha Ndi<br />
Email: Lethinh.ies@gmail.com<br />
Tom tat:<br />
Tdm tdt - Bdi todn ddt ngudn diin phdn tdn (DG - Distributed Generation) vdo<br />
vi tri tdi uu trong lutyi diin mang Igi nhiiu Igi ich vi kinh ti vd ky thuat nhu cdi<br />
thien chdt lucmg diin dp, gidm tdi thiiu tdn thdt cdng sudt trong luoi diin phdn<br />
phdi. Bdi bdo ndy gioi thiiu phuang phdp tinh todn lua chon vi tri tdi uu dgt DG<br />
trong ludi diin theo cdch tinh todn tdn thdt thdng qua hi sd B (loss coefficient hay<br />
B-coefficient) dugc dua ra boi Kron [4]. Kit qud tinh todn thir nghiem vai ludi<br />
phdn phdi 40 nut cho thdy phuang phdp di xudt cd uu diim nhanh vd sai sd kit<br />
qud nhd so vai cdc chuong trinh tinh todn hien nay, phucmg phdp cd thi dp dung<br />
tinh todn lua chon vi tri tdi uu ddt DG trong luoi dien phdn phdi<br />
Abstract:<br />
Abstract - The mathematical problem of placing Distributed Generation (DG)<br />
into optimal position of electrical grid will bring many economic and technical<br />
advantages such as improving voltage quality, minimizing power loss in<br />
distributed system. This article presents the method of computing and choosing<br />
optimal position for placing DG in electrical grid based on loss calculating<br />
method through B-coefficient presented by Kron [4]. Result ofpilot calculation in<br />
distributed grid of 40 nodes shows that the proposed method is quick and its error<br />
is low compared with existing computational program, computing and choosing<br />
optimal position for placing DG can be applied in distributed electrical grid.<br />
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1. GlOfI THIEU<br />
Cac ngudn nang lugng tai tao, phan tan (DG - Distributed Generation) ngay cang phat triln<br />
manh me tren the gidi. C5 My, ngudn DG hoac ngudn phat khac chilm hon 30%) trong sl<br />
nguon dien phat [2]. Theo bao cao ciia Hdi ddng quoc tl He thong dien ldn (CIGRE-<br />
Intemational Council on Large Electric System) ngudn DG hien tai chilm 31% a Dan Mach<br />
va chiem 40% d Ha Lan [2]. Nghien ciiu du bao cua Td chiic Khi Tu nhien (Natural Gas<br />
Foundation) thi ngudn phat mdi DG se chiem 30%) vao nam 2010 [3].<br />
Trong no lire de dat dugc 5%o ngudn nang lugng so cip tir nang lugng tai tao vao nam 2020<br />
cua Viet Nam, cac ngudn dien phan tan nhu: dien gid, dien mat trdi, thuy dien nhd, dien sinh<br />
khdi... dang rat dugc chii y, quan tam phat trien tai Viet Nam.<br />
Bai toan dat ra la, xac dinh diem dau ndi ngudn DG vao ludi dien qudc gia sao cho he<br />
thdng dat dugc chi tieu giam tdn that cdng suat tac dung tren ludi, dam bao cho ludi dien van<br />
hanh kinh te nhat.<br />
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346<br />
Hdi nghi Khoa hgc ky niem 35 ndm Viin Khoa hgc vd Cdng nghe Viet Nam - Hd Ndi 10/2010<br />
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Da cd mdt sd phuong phap tinh toan giai bai toan neu tren nhu phuong phap sir dung do<br />
nhay tdn that cua mit phu tai [6]. Cac mit dugc sap xep theo thii tu do nhay tdn that ciia<br />
chiing, dung lugng cua DG tai mdi mit dd dugc giir va cho tang dan tdi khi tdn that tang. Vi<br />
tri tim dugc la vi tri DG dua ra tdn that giam nhieu nhat tai vi tri do. Do nhay tdn that cua cac<br />
nut thay ddi ciing nhu khi chiing ta tang dung lugng cua DG. Phuong phap sir dung thuat toan<br />
di truyen (GA) giai quyet bai toan tim vi tri tdi uu dat cua DG ciing da dugc nghien ciiu ling<br />
dung [5]. Cac phuong phap tinh tren cd dac diem phii hgp vdi bai toan da muc tieu va giai<br />
phap gan tdi uu cho cac bai toan nhung ddi hdi tinh toan chuyen sau va thdi gian hgi tu lau.<br />
Bai bao nay gidi thieu ket qua nghien ciiu ung dung phuong phap sir dung he so tdn that<br />
"B" (loss coefficient hoac B-coefficient) do Kron [4] de xuat, tinh toan vi tri tdi uu dat DG vdi<br />
muc dich giam tdn that cdng suat tac dung tren ludi dien. Phuong phap nay cd uu diem la don<br />
gian, tinh toan nhanh va sai sd nhd hon so vdi cac chuong trinh sir dung phuong phap tinh<br />
toan khac nhu hien nay.<br />
2. PHUONG PHAP SU* DUNG HE SO TON THAT "B" XAC DINH VI TRI TOI UU<br />
DAT DG<br />
Ham muc tieu cua bai toan duoc viet nhu sau:<br />
<br />
^L=YJ\ A^^{P^Pj+Q,Q^) + B,j{Q,P^-P,Q^) ] -.Min (1)<br />
,=1 y=l<br />
<br />
R.Cos (S,-Sj]<br />
A,=<br />
Vdi (2)<br />
R,^ Sin {5,-5)<br />
B.<br />
vy><br />
Trong dd: Pi va Qi la cdng suit tac dung va cdng suit phan khang mit 'i'; Vi va 5i la dien<br />
ap va gdc pha cua mit 'i'<br />
Rij + Xij = Zij; trong dd Zij la thanh phin ij cua ma tran [Zbus] vdi [Zbus] = [Ybus]-1<br />
<br />
Can bang cdng suat: Z Po, - I Pt. + AP, (3)<br />
/=!<br />
Trong do: APL la tin thit cdng suit tac dung trong he thdng; PGi va PDi la cdng suit<br />
ngudn phat va cdng suat tai tai mit i.<br />
Ddi vdi cac loai nguon DG nhu dien mat trdi se chi cung cip cdng suat tac dung, con ddi<br />
vdi tuabin gid ngudn phat dugc sir dung dl tao ra cdng suat tac dung va trong qua trinh dd se<br />
tieu thu cdng suat phan khang.<br />
Ting dung lugng cdng suit phan khang tir DG (ngudn tua bin gid) don gian cd thi dugc<br />
tinh toan theo bilu thiic (3) nhu sau [1]:<br />
e^^=:-(0.05 + 0.04P^)<br />
(4)<br />
Tir (1) va (3), vilt lai cdng thiic tinh AP^ nhu sau:<br />
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347<br />
Tieu ban: Mdi truong vd Ndng lugng ISBN: 978-604-913-013-7<br />
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'^,j[(PoG,-Poi)Pj+(-0.05-0.0AP^„-Q,,)Qj]<br />
(5)<br />
/=i j=\ + B^[{-0.05~0.04P^,^-Q,,)P^-{P,„-P„)Q^]<br />
<br />
Phuong phap tinh toan dugc thuc hien theo cac budc sau:<br />
<br />
Bat dau Doc dir lieu dau vao Dua ra ton that he thong ban dau<br />
<br />
<br />
Dira ra ton that nho Dua DG vao tirng vj tri nut va tinh toan ton that he thong<br />
nhit khi dat DG Lap lai cho tat ca cac vj tri mit dat DG<br />
Lull ket qua tinh toan cho tirng niit dat DG<br />
<br />
Tai vj tri ton that he thong nho nhat se dua ra vj tri<br />
toi uu ciia moi dung luong DG dat tai vj tri do In ket qua Ket thiic<br />
<br />
3. Ket qua tinh toan thir nghiem<br />
Phuong phap de xuat dugc ap dung tinh toan thir nghiem cho ludi dien phan phdi cd 40 niit<br />
d cap dien ap 22kV (xuat tuyen 473-E2 Ddng Hdi, thudc Dien lire tinh Quang Binh). Tdng<br />
cdng suat tac dung ciia phu tai Ptai = 8.227MW va tdng cdng suat phan khang ciia phu tai<br />
Qtai = 5.745 MVAr. Tdn that cdng suat tac dung ban dau cua he thdng khi chua dat DG la<br />
APbd = 197.988 kW va AQbd = 273.829 kVAr.<br />
hm Cnig Quya Till Cdng Ciu<br />
250 400<br />
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S .13 MDBaGii Kim DL Lit Hinh M? CAuh CTCN Tai. Thuy NTTSBaoNmh<br />
650 650 320 1120 320<br />
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IN<br />
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NM. Ddng Tiu N.M Ngh^ Mnh DTCV sang LOy<br />
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Hinh 1: So do ludi diin xudt tuyen 22kV-E2 Ddng Hdi<br />
Tmdng hgp cac ngudn DG chi cung cap cdng suat tac dung P. Vdi cac cdng suit DG khac nhau,<br />
chiing ta tun dugc cac vi tri khac nhau dat DG dam bao dugc tdi thieu hda tdn thit cdng suit.<br />
- Khi dat DG vdi dung lugng PDG = 4MW thi vi tri tdi uu nhit la "niit 19" tuong ling vdi<br />
tin thit he thing nhd nhit AP = 91.977kW va AQ =127.142 kVAr.<br />
- Khi dat DG vdi dung lugng PDG = 5MW thi vi tri tdi uu nhit la "mit 18" tuong ung vdi<br />
tin thit he thdng nhd nhit AP = 80.297kW va AQ = 110.974kVAr.<br />
- Khi dat DG vdi dung lugng PDG = 6.5MW thi vi tri tdi uu nhit la "mit 16" tuong ling vdi<br />
tin thit he thing nhd nhit AP = 72.113kW va AQ = 99.610kVAr.<br />
- Trong hinh 2 cho ta thiy khi dat DG vdi dung lugng PDG = 6.5MW thi tdn thit he thong<br />
la nhd nhat so vdi cac tmdng hgp khac.<br />
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348<br />
Hdi nghi Khoa hgc ky niem 35 ndm Viin Khoa hgc vd Cdng nghi Viet Nam - Hd Ndi 10/2010<br />
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Ton that cua he thong tai vj tri tCrng niit<br />
• Khi aat P-DG = 4MW<br />
« Khi dat P-DG = 5 MW<br />
<br />
• Khi flat P-DG = 5,5 MW<br />
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Hinh 2: Tdn thdt he thdng khi ddt DG tgi cdc vf tri nut khdc nhau<br />
Di#n ap tai vj tri nut giam tdn that hi thdng nho nh^t<br />
<br />
<br />
<br />
<br />
— Dien Ap ban dau<br />
— Dien Sp khi ast P-DG=4MW t?i vj tri nut 19<br />
004<br />
— Dien Sp khi aat P-De=5MW tgi vi tn' nut 13<br />
093 — Dien cip khi ast P-D6=B.5MW tgi vj tri nut 16<br />
<br />
<br />
<br />
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Hinh 3: Dien dp tgi vi tri niit tdi uu trong cdc trudng hgp khdc nhau<br />
Dd thi d hinh 3 cho ta thay khi dat DG vdi dung lugng PDG = 6.5MW thi chat lugng dien<br />
ap la tdt nhat so vdi cac trudng hgp khac, vdi dien ap thap nhat la 0.9801 p.u.<br />
Bdng 1: Tdn thdt hi thdng khi ddt DG tgi mdt sd nut diin hinh<br />
He thdng ban dau khi chua dat DG<br />
ZPta, IQtai APbd AQbd AP/(ZPta,+AP) AQ/( IQtai +AQ)<br />
TT<br />
(kW) (kVAr) (kW) (kVAr) % %<br />
1 8227 5745 197.988 273.829 2.35 4.55<br />
He thdng sau khi dat DG<br />
PDG AP AQ |AP - APbdl/ APbd |AQ - AQbdl/ AQbd<br />
TT Nut<br />
(MW) (kW) (kVAr) % %<br />
Khi DG vdi cdng suit PDG = 4MW<br />
1 19 4 91.977 127.142 53.54 53.57<br />
2 37 4 92.092 127.279 53.49 53.52<br />
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349<br />
Tiiu ban: Mdi tru&ng vd Ndng lugng ISBN: 978-604-913-013-7<br />
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3 18 4 92.177 127.422 53.44 53.47<br />
Khi DG vdi cdng suit PDG = 5MW<br />
1 18 5 80.297 110.974 59.44 59.47<br />
2 17 5 80.328 111.017 59.43 59.46<br />
3 19 5 80.564 111.348 59.31 59.34<br />
Khi DG vdi cdng suit PDG = 6.5MW<br />
1 16 6.5 72.113 99.610 63.58 63.62<br />
2 15 6.5 72.294 99.862 63.49 63.53<br />
3 17 6.5 72.435 100.061 63.41 63.46<br />
Trudng hgp cac ngudn DG cung cap cdng suat tac dung P va tieu thu cdng suat phan khang<br />
Q: Tinh toan cho cac phuong an: (i) dat DG phat PDG = 3MW va tieu thu QDG = 0.41 MVAr;<br />
(ii) dat DG phat PDG = 4.5MW va tieu thu QDG = 0.86 MVAr; (iii) dat DG phat PDG = 5MW<br />
va tieu thu QDG = 1.05MVAr, vi tri tdi uu dat DG lan lugt la cac niit 19; 18 va 17.<br />
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4. KET LUAN<br />
Ung dung phuong phap sir dung he sd tdn that "B" (loss coefficient hoac B-coefficient)<br />
tinh toan vi tri tdi uu dat DG vdi muc dich giam tdn that cdng suat tac dung tren ludi dien<br />
theo md hinh do Kron de xuat cd uu diem la tinh toan nhanh, cho ket qua kha chinh xac va de<br />
xay dimg chuong trinh tinh trong mdi trudng MATLAB.<br />
Tuy vay, bai toan nay mdi tinh den chi tieu tdn that cdng suat tren ludi khi tim cac diem<br />
dat va quy md cdng suat cua DG trong dieu kien cd dinh cac chi tieu kinh te, ky thuat khac<br />
cua ngudn DG. De giai quyet trgn ven bai toan xac dinh tdi uu diem dat cac DG trong ludi<br />
dien, can nghien ciiu md rdng dua cac chi tieu kinh te, ky thuat khac ciia ngudn DG khi thay<br />
ddi diem dat va quy md cdng suat vao dieu kien dau vao cua bai toan. Day ciing la muc tieu<br />
nghien cuu tiep theo cua de tai.<br />
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TAI LIEU THAM KHAO<br />
1. DTI, 2004, "Network Performance Benefits of Energy Storage for a Large Wind<br />
Farm", Retrieved Febmary 7, 2005.<br />
2. CIGRE, "CIGRE Technical Brochure on Modeling New Forms of Generation and<br />
Storage Tf 38.01.10", November 2000, Retrieved Febmary 3, 2005.<br />
3. P. P. Barker, R. W. De Mello, "Determining the Impact of Distributed Generation on<br />
Power Systems. I Radial distribution systems", in Proc. IEEE Power Engineering<br />
Society Summer Meeting, Vol. 3, Seattle , WA, 16-20 July 2000, pp. 1645-1656.<br />
4. Hadi Saadat, 1999, "Power System Analysis", McGraw-Hill Companies, Singapore<br />
(Book reference).<br />
5. G. Carpinelli, G. Celli, A. Russo, "Distributed Generation Sizing and Siting Under<br />
Uncertainity", Proc. of IEEE Porto Power Tech, 2001.<br />
6. Zhu, J.Z. Hwang, D. Sadjadpour, A. Alstom EAI, Bellevue, WA, USA, "Loss<br />
sensitivity calculation and analysis ".<br />
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