Sup Do Dien AP Trong Luoi Co DG

Science & Technology Development, Vol 14, No.K2- 2011

Trang 80

NGHIN CU CC C TRNG SP IN P TRONG LI IN C KT

NI NH MY IN GI

Trnh Trng Chng

Trng i hc Cng nghip H Ni

TM TT: S lng cc nh my in gi ang ngy cng gia tng nc ta, tng cng sut

lp t tnh n cui nm nay d kin t 50 MW. Vi mc gia tng ngy cng ln vo h thng in,

trong cng tc quy hoch v vn hnh cn thit phi c cc nghin cu v nh hng ca chng n

cc h thng in, do c im ca ngun in ny kh khc bit so vi cc ngun in truyn thng

khc, trong cc cp in p phn phi khi kt ni vi in gi s c nhng nh hng ng k nht.

Ni dung chnh ca bi bo ny l kho st mc n nh ca li in kt ni cc ngun in gi ti

nt kt ni chung (PCC) khi thay i lng cng sut tc dng v phn khng ca my pht in gi

cho n khi din ra hin tng sp in p xc nh cc iu kin lm vic gii hn. Gii hn lm

vic n nh ca in gi c nghin cu da trn cc tiu chun n nh, t xc nh cc khu yu

cn quan tm: nhnh, nt... xut gii php nng cao n nh v lm vic tin cy ca h thng

cung cp in (HTCC).

T kho: sp in p, in gi, n nh tnh

1. GII THIU

Kh nng lm vic n nh ca nh my

in gi (WP) trong cc H thng cung cp

in (HTCC) ph thuc cc iu kin nh:

cng ngh my pht in gi, dung lng v

cng ngh thit b b cng sut phn khng ca

in gi, " mnh" ca li in m chng

kt ni...Vn ny c t ra lin quan n

s pht trin ngy cng mnh m, a dng ca

WP v cc li in. Vi cc nt nm gn WP,

in p c th s c nguy c gim thp v dao

ng mnh, dn n sp in p. c rt

nhiu nghin cu v nh hng ca WP n n

nh in p v cht lng in nng trong

HTCC [5, 7, 8], tuy nhin cc nghin cu

cha thc s cp n cc c trng n nh

v gii hn vn hnh ca cc phn t ng vai

tr quan trng trong HTCC. Trong bi bo

ny tc gi tp trung nghin cu cc ch tiu

nh gi mc n nh in p, t xc

nh cc khu "yu", v xut bin php nng

cao n nh in p trong h thng in c kt

ni WP.

2. MT S CH TIU NH GI N

NH IN P NT

i vi HTCC, vic nh gi c xy

dng trn gi thit thanh ci ngun cung cp c

cng sut v cng ln. Gi thit ny c ngha

khi xy dng m hnh ca in gi, theo cc

nh hng "nhiu" nh: chp chn in p (do

hiu ng ct thp), dao ng in p (do thay

i tc gi)...pht sinh t tuabin gi khng

TAP CH PHAT TRIEN KH&CN, TAP 14, SO K2 - 2011

Trang 81

nh hng nhiu n s hot ng bnh thng

v cht lng in p ca h thng in v ph

ti. phn tch ch vn hnh mt n nh

ca chng c th s dng cc tiu chun v sp

in p nh: phn tch nhy, phng

php lin tc, phn tch gi tr ring, phn tch

tro lu cng sut....Trong bi bo ny, tc gi

s tp trung nghin cu ng dng cc tiu

chun thc dng, xy dng min n nh in

p trn mt phng cng sut nh gi gii

hn sp in p trong cc HTCC c kt

ni WP.

2.1. Ch s st p L (L - indicator)

Mt h thng in 2 nt nh hnh 1, trong

c mt nt ngun (G) v mt nt ti (L).

c phng trnh vit dng ng nht, cng

sut ti nt L vn c tnh theo chiu i vo

nt G nhng mang du m. Ch s L c nh

ngha nh sau [1]:

1121

112

101YV

S

YV

S

V

VLD

DD

==+=

(1)

Trong trng hp tng qut mt h thng

in c nhiu nt ngun v nhiu nt ti, cc

nt ny c th hin 1 trong 2 dng: nt PV

(i vi cc nt ngun) v nt PQ (i vi cc

nt ti). in p ti nt th j nh hng bi

cng sut v in p ca ngun in tng

ng v cch biu din l tng t vi trng

hp hnh 1.

Hnh 1. H thng in 2 nt

Ch s n nh in p ti nt ti th j

c cho bi:

' '0

22 '

1.

j j jj

j jjj j jj

U S SL

U YU U Y

= + = = (2)

iu kin n nh ca h thng l Lj


Trang 82

'

1

kmm mN

kjjj k

YU UY

=

=

(4)

vi: Uk l in p pha ti nt k; Um l in

p pha ti nt m; Ykm l tng dn gia nt k v

nt m; Ykj l tng dn gia nt k v nt j; m l

nt c ni vi nt k. Gi tr ca VCPI nm

trong phm vi t 0 n 1, nu VCPIi ca mt

nt no bng 1 th nt xem nh mt n

nh in p. Gi tr VCPI kh thun li cho

vic xc nh cc nt "yu" trong HT.

2.2. Cc ch tiu nh gi n nh in

p nt khi tnh bng chng trnh

2.2.1. Cc ch tiu chung

a. d tr n nh theo kch bn in

hnh

Mt trong nhng kch bn thng hay xy

ra: l s gia tng t l cng sut ph ti cc nt,

phn b vo cc my pht theo c tnh iu

chnh tnh. Nu trong ch hin hnh tng

cng sut ti l P0, n gii hn ti c tr s l

Pgh th h s d tr c nh ngha bi [6]:

%1000

0

=P

PPK ghdt (5)

Ch tiu ny c th d dng xc nh c

bng cc chng trnh tnh ton gii hn n

nh.

b. d tr n nh theo cc kch bn

quan tm

+ Kch bn theo cc yu cu vn hnh

H thng c th vn hnh theo cc phng

thc khc nhau theo yu cu huy ng cng

sut. tm gii hn n nh cn lm thay i

t t cc thng s t ch hin hnh sang

phng thc mi. H s d tr n nh c dng

[6]:

%1000

0

i

ighidt P

PPK

= (6)

y cng sut Pi l thng s quan tm,

thay i trong phng thc vn hnh mi.

+ Kch bn nguy him nht

V l thuyt, t mt trng thi hin hnh

c mt kch bn nguy him nht l kch bn

i theo ng ngn nht n bin gii min n

nh. Nu bit ng i ngn nht ny c th

nh ngha h s d tr [6]:

%1000

0

i

ighidt L

LLK

= (7)

Li l thng s c trng cho hng i ngn

nht n gii hn n nh. Trong trng hp

chung, vic xc nh hng i nguy him nht

l bi ton kh phc tp, v th ch tiu ny

thng s dng cho cc trng hp ring.

c. Min n nh cc nt

Gi s xy dng c ng c tnh gii

hn n nh hp vi h trc ta xc nh

c min lm vic cho php trn mt phng

cng sut nh hnh 2.

Hnh 2. Min n nh trn mt phng cng sut

y O(Q0,P0) l mt im lm vic n

nh (cng sut nt ti). Cn c vo khong


Trang 83

cch t O n ng gii hn cho php xc

nh c d tr n nh, oa l d tr

cng sut tc dng khi gi Q khng i, oc l

d tr cng sut phn khng khi gi P

khng i v ob l d tr n nh khi gi h

s cng sut khng i. xc nh c

ng c tnh gii hn ti mt nt ph ti, c

th s dng phn mm tnh ton gii tch mng

in v phng php lm nng ch . Gi c

nh gi tr P, tng dn Q cho n khi h thng

chuyn t trng thi n nh sang trng thi

mt n nh, ti xc nh c mt im

trn c tnh gii hn, thay i P v tnh ton

tng t s tm c tp hp im nm trn

c tnh gii hn, ni cc im ny li xc nh

c min lm vic cho php ca cng sut

ph ti theo iu kin gii hn n nh. Da

theo cc ch tiu nh gi gii hn n nh, s

tm c ch xc lp, min lm vic cho

php theo gii hn n nh tnh.

2.2.2. Cc ch tiu ring

Ngoi cc ch tiu phn tch mc n

nh chung cho h thng, phn tch cc yu

t nh hng n tnh n nh ngi ta cn a

ra cc ch tiu ring [6].

a.H s st p cc nt ( nhy dao ng

in p)

%100U

UU%k

0

gh0U

= (8)

trong U0 v Ugh tng ng l tr s in

p nt ch ang xt v ch gii hn.

Vi cng mt kch bn nt c kU% ln l cc

nt yu.

b.H s bin thin cng sut nhnh

%100P

PP%k

0

0ghP

= (9)

vi P0 v Pgh tng ng l tr s cng sut

truyn ti trn nhnh ch ang xt v

ch gii hn. Vi cng kch bn nhnh c

kP% ln l nhnh nguy him.

2.2.3. Nhn xt chung

Ch tiu tng hp nh h s d tr (kdt)

theo kch bn in hnh c th dng nh

gi mnh ca ton li v phng din n

nh, c ngha kim tra ring cho tnh hung

tng ti t ngt hay c t bin cng sut pht

ca in gi (ng/ct tuabin ra khi li). Tuy

nhin cc ngun in gi c cng sut thng

khng ln, kh c th gy ra t bin cho h

thng, do vy vic s dng ch tiu ny nh

gi cho h thng c kt ni ngun in gi s

cho ngha c trng cho tin cy n nh

khng tht r rng.

Cc ch tiu ring kU, kP t ra ph hp hn,

n cho php xc nh nhanh cc nt yu, nhnh

yu xut bin php ci to. Mi phng

thc vn hnh v mc pht cng sut khc

nhau ca in gi s a ra mt gi tr ch tiu

xc nh. Ch tiu n nh in p nt Lj c

s dng nhiu i vi cc h thng in nhiu

dng ngun pht khc nhau, rt ph hp i

vi li in phn phi; cho php xc nh gi

tr gii hn ti a ca ti hay kh nng pht

cng sut cc i ca WP vo h thng. Min

n nh l ch tiu ring c th cho bit mt nt

c th pht hay nhn ti a bao nhiu cng

sut. Do vy kho st min n nh theo khng

gian cng sut nt cng c th a ra nhiu


Trang 84

thng tin c li nh gi mc n nh h

thng. Ch tiu ny c th c p dng trong

cc h thng in c kt ni my pht khng

ng b nh WP, theo s cho bit kh nng

pht trin ph ti ca HTCC.

3. M HNH CNG SUT CA WP

Trong trng hp chung, cc nt kt ni

WP c th c m t nh mt nt PQ hay nt

PV, cng sut pht ph thuc in p. Trong

[3] m t cng sut pht ca WP di dng:

2

W 2. .P n sp ip zpn n

U UP P C C CU U

= + + (10)

y cc h s Csp, Cip, Czp biu din t

trng thnh phn P(U) ca WP khi coi chng

tng ng vi cng sut hng, dng in hng

hay tng tr hng; Udm, Pdm l cc gi tr nh

mc ca in p, cng sut tc dng. RU l h

s hiu chnh ph thuc cc iu kin khc

nhau.

Thng thng khi c dao ng tc gi

v in p li in thay i th cng sut pht

cng dao ng. T khi bt u khi ng

tuabin (khi cha t n gi tr nh mc) cng

sut pht bt u tng dn, in p my pht

cng thay i t gi tr khi im Ub2 ln n

gi tr Ub1, trong in p Ub1 l gi tr m

tc gi v cng sut pht xp x gi tr nh

mc. Trong khong gi tr [Ub1; Ua1] tuabin gi

lm vic n nh, cc gi tr in p v cng

sut t gi tr nh mc. Khi tc gi vt

qua gi tr "cut out", ng vi gi tr in p

U>Ua1 th tuabin s c ct ra khi li in.

in p U trn hnh 3 cng c xem xt khi U

l in p pha li in. Nu gi tr ny st

gim s lm gim cng sut pht tc dng P(U)

ca in gi v tng lng cng sut phn

khng m my pht s nhn t li in.

Hnh 3. c tnh cng sut ca WP ph thuc in

p

Do vy trong thc t mt h s hiu chnh

RU s c thm vo m hnh pht cng sut

ca in gi P(U) theo tc gi v in p

my pht. ng vi ng c tnh cng sut

tuabin gi, nu U>Ua1 hay U < Ub1 th RU s c

gi tr nm trong khong t 1 n 0 tu theo gi

tr ca vn tc gi ("cut in" hay "cut out") v

tng ng s c cc gi tr cng sut Pdm ca

WP. Vi mt tp hp nhiu tuabin gi trong

WP cung cp cng sut nh mc Pm th RU c

gi tr xp x bng 1. Trong a s cc trng

hp, thc nghim cho kt qu: Ua1 = 1,2pu;

Ua2 = 1,3pu; Ub1 = 0,7pu; Ub2 = 0.1 pu. Theo

hnh 3, trong [3] xc nh quan h gia RU

v in p U nh sau:

2

11

1 2

1 1

2

11

1 2

max 1 ;0

1

max 1 ;0

bb U

b b

b b a U

aa U

a a

U UU U RU U

U U U R

U UU U RU U

< = =

> = (11)

Pm

P

U Ub2 Ub1 Ua1 Um Ua2


Trang 85

Cc thng s Ua1, Ua2, Ub1, Ub2 c ngha

quyt nh n h s hiu chnh RU, cng vi

cc h s Csp, Cip,, Csq, Ciq biu din s thay i

cng sut pht ca my pht (WP), trong :

Cip + Csp + Czp = 1. Theo phng trnh cng

sut c biu din bi:

( )22. . . . , , , , ,n U sp U ip zp n U sp ip zp nn n

U UP P R C R C C P R C C C UUU U

= + + =

(12)

Tng t cng c th xy dng c mi

quan h gia Q ca in gi vi in p ca

li in nh sau:

( )22. . . . , , , , ,n U sq U iq zq n U sq iq zq nn n

U UQ Q R C R C C Q R C C C UUU U

= + + =

(13)

y Ciq + Csq + Czq = 1. Nh vy ng vi

mt tc gi xc nh s tm mt gi tr in

p v cng sut pht tng ng ca in gi.

Biu thc (12) v (13) c tnh tng qut, th

hin c nhiu tnh hung lm vic ca in

gi khi tc gi v in p thay i. Gi UPCC

l in p ti nt kt ni my pht WP vi li

in (hnh 4) v Zkn = Rkn +jXkn l tng tr

ng dy kt ni, m l t s bin p. Nu b

qua tn tht nng lng v tn tht in p ca

MBA ta s tm c quan h gia cng sut

WP vi in p li in nh sau:

( / )PC C luoiPC C kn kn

U U mP jQU R jX

+ = + (14)

Hnh 4. M hnh kt ni WP vi h thng cung cp

in

Theo (14) thy rng khi in p ti im

kt ni suy gim mnh th lc ny WP s hot

ng nh mt ng c khng ng b v nhn

cng sut t pha h thng v, iu ny d gy

mt n nh in p v nh hng ln n kh

nng pht cng sut ca chng. Gii php

thng p dng trng hp ny l s dng cc

thit b c iu chnh nh SVC, STATCOM

[8].

4. NG DNG TNH TON

Li in khu vc Ninh Thun nm 2015

c mt WP cng sut 20 MW ni li in 22

kV, sau kt ni vi li in 110 kV nh

hnh 5 [4]. My pht s dng l loi my in

khng ng b ngun kp DFIG (ca hng

VESTAS-an Mch). Cng sut nh mc mi

tuabin my pht l 2 MW kt ni vi li in

phn phi 22 kV qua my bin p 0,69/22 kV -

2MVA. S hiu cc nt cho trong hnh 5. c

tnh cng sut my pht theo tc gi cho

trong hnh 6.


Trang 86

Hnh 5. Li in Ninh Thun nm 2015

0

500

1000

1500

2000

2500

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

m/s

Cng

sut

, kW

Hnh 6. c tnh cng sut ca my pht DFIG

(VESTAS) - 2 MW

Gi thit tt c cc tuabin gi ti thi im

tnh ton u nhn c mt nng lng gi

nh nhau. Mt khng kh bng 1,125 kg/m3,

cao ct thp 60m. Vi bin thin tc gi

trung bnh Ninh Thun t 10 m/s n 16 m/s

th di gi tr ny cng sut pht khong 1,5

MW. Khi tc gi nm trong khong 16 m/s

n 25 m/s th UMF = Ua1 = 1,2 pu v cng sut

pht n nh mc 2,03 MW. Khi tc gi

vt qu 25m/s, tuabin gi s c ct ra khi

li in.


Trang 87

nh gi n nh in p nt qua cc

ch tiu

T m hnh cng sut ca my pht in

gi, ti gi tr tc gi v = 16 m/s ng vi

ng c tnh cng sut, xc nh c cng

sut pht ca mi my pht trong ch xc

lp (RU = 1). Ch c bn l WP ch pht

cng sut tc dng P theo m hnh (12), tin

hnh xc nh gi tr in p gii hn ti mi

nt, theo tm c ch s VCPI tnh theo

cng thc (3) thng qua gi tr in p v tng

dn nt. Theo kt qu tnh ton trong hnh 7

(nt 1 l nt cn bng); c th nhn thy cc

nt 18, 99, 100 v t 101 n 110 l cc nt c

ch s VCPI ln, y l cc nt yu trn

phng din n nh in p. Mt s nt cng

c ch s VCPI kh cao: nt 17, nt 20 - y l

nhng nt nm ln cn nt kt ni WP.

Kt qu tnh ton ch s n nh in p

nt L cho nt 100 hnh 8 cho thy: nt ny s

mt n nh ti gi tr cng sut 22,5 MW (lc

ny L = 1), in p gii hn Ugh = 0,61pu. Khi

nt kt ni cc my pht in gi mt n nh

cng lm nh hng ng k n ch lm

vic ca cc nt khc, thng s ch th L mt

s nt ln cn c xu hng gia tng. Trong

hnh 8 cng m t nh hng ca ch s L nt

100 n nt 19 (thay i thng s nt 100 cho

n khi mt n nh, trong khi gi nguyn cng

sut nt 19). Ti gi tr sp in p ca nt

100, thng s ch th L ca nt 19 tng t gi tr

ban u L = 0,05 ln gi tr L = 0,2, kt qu

biu din trn hnh 8.

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 30 32 34 99 100Nt s

VC

PI

Hnh 7. Ch s VCPI cc nt ca li in Ninh

Thun

0

0,2

0,4

0,6

0,8

1

1,2

10 11 12 13 14 15 16 17 18 19 20

P, MW

pu

L-100

U-100

L-19

Hnh 8. nh hng ca qu trnh mt n nh in

p nt 100 n nt 19

Vi thng s ch vn hnh nm 2015,

tng ph ti ca P0 ca Ninh Thun l 251MW.

Gi thit tng ng thi ph ti cc nt (cng

t l), cng sut my pht tng theo h s iu

chnh tnh s tm c ch gii hn tng

ng vi Pgh. S dng chng trnh CONUS

(B mn H thng in - i hc BK HN), m

t cng sut pht ca WP theo cng thc (12)

v (13) kt hp vi m hnh li in Ninh

Thun nm 2015 tm c h s d tr n nh

bng 57,7%. Bng 1 l kt qu tnh ton ch s

st p ca cc nt ti ca li in Ninh Thun.

T bng ny thy rng cc nt c ch s st p

khc nhau, ngoi ra cn th hin tr s in p

nt trc khi h thng mt n nh. Kt qu

ny cng ph hp vi kt qu xc nh cc nt


Trang 88

yu bng ch s L. Nt kt ni vi WP (nt 99)

c ch s st p ln nht, cc nt khc (t nt

100 n nt 110) l nt kt ni my pht in

tuabin gi vi li in a phng (thanh ci

22 kV trm Phc Ninh) u c ch s st p >

20%. C th hiu cc nt yu v phng

din n nh in p (nt nh du "*").

Bng 1. Ch s st p cc nt

Bng 2. nhy bin thin cng sut nhnh

Trong bng 2 trnh by kt qu xc nh

nhy bin thin cng sut nhnh pht hin

cc nhnh yu trong iu kin c WP. Kt qu

cho thy cc nhnh kt ni vi WP u rt d

mt n nh nu xy ra bin ng t ngt ca

ph ti hay khi tng cng sut truyn ti ca

nhnh kt ni. Qua bng 2 cho thy nhnh 12 -

18 v nhnh 3-12 c cc h s kP% ln nht v

cch bit so vi cc nhnh khc, y l nhng

nhnh "yu" v mt n nh tnh, cn c bin

php ci to nng cao mc n nh.

Mt b b tnh cng sut 10 MVAR gi

thit lp t ti nt 99, gii php ny c so

snh vi trng hp cu trc li li in gn

khu vc WP. Gii php cu trc li li in

c thc hin l: do v tr a l ca trm bin

p Vnh Ho v trm bin p Ninh Phc i

qua khu vc WP, do thay th ng dy lin

lc gia 2 nt ny bng cch: xy dng ng

dy 110 kV kt ni 2 trm bin p ny vi trm

bin p 110 kV Phc Ninh (nt PCC) to

thnh cc mch kp. Ti nt PCC s c 4 xut

tuyn lin lc vi h thng, trong hnh 9 trnh

by hiu qu cc gii php nng cao n nh

ca li in Ninh Thun.


Trang 89

Khng c WF

-20

0

20

40

60

80

100

-10 0 10 20 30 40 50

Q

P

C WF

0

20

40

60

80

100

120

-20 -10 0 10 20 30 40

Q

P

C WF, c b

-20

0

20

40

60

80

100

120

-20 -10 0 10 20 30 40 50

Q

p

C WF, cu trc li li in v c b

-20

0

20

40

60

80

100

120

140

-20 -10 0 10 20 30 40 50

Q

P

Hnh 9. Min n nh nt 99 trn mt phng cng sut trong cc phng n

Kt qu tnh ton cho thy h s d tr n

nh ca h thng tng t 57,7% (trng hp

c bn) ln 75,7% khi c t b b tnh. ng

cong bin thin in p cc nt trong h thng

cng c ci thin r rt, min n nh in

p nt 18 c tng thm ng k. Trong

trng hp c bn khi khng b cng sut

phn khng nu tin hnh ci to nhnh 12 -18

bng cch thay dy dn AC 185 bng dy dn

ACSR 330, mc d tr n nh h thng tng

thm 6,8%, t gi tr 64,5% nh hnh 10, ng

thi in p cc nt c ci thin, h s st p

nt 99 gim t 22,19% xung cn 19,69%.

Mc mang ti cc nt tng t gi tr k = 1,57

ln k = 1,63.


Trang 90

a)

b)

Hnh 10. Min n nh in p cc nt trc (a) v sau ci to (b)

Trong bng 3 trnh by kt qu xc nh

cc thng s ch ti nt s 18 trong cc iu

kin: khng c kt ni WP (iu kin A); c

kt ni WP nhng khng t thit b b (iu

kin B) v c kt ni WP, ng thi c t b

b tnh 10 MVAR (iu kin C).


Trang 91

Bng 3. Thng s nt 18 trong cc iu

kin vn hnh khc nhau

iu

kin

in p

khi im

U0, kV

in p

gii hn

Ugh, kV

Ch s st

p nt, %

D tr n

nh h

thng,%

A 111,37 90.03 19,1 104,2

B 109.69 95,36 13,06 57,7

C 113,23 98,92 12,64 75,7

C th thy khi c s tham gia ca ngun

in gi, in p ti nt kt ni cng nh cc

nt khc c ci thin, tuy nhin mc d tr

n nh in p thp hn do kh nng pht

cng sut phn khng hn ch ca WP. Khi c

s tham gia ca WP v khi t t b, in p

vn hnh v in p gii hn c nng ln

nhng c gi tr kh gn vi in p khi im

v in p gii hn. iu ny cng c th c

gii thch bng m t ton hc l: Tr s dung

dn ca t in s c tnh cng thm vo tr

s phn t tng dn Y. Nh vy khi xt v

quan h ton hc s lm gim tnh tri ca ma

trn tng dn nt, tc l lm gim kh nng xc

nh nghim in p m phng trng thi xc

lp ca h thng.

Mt c im cng d nhn thy l: khi

m t in gi nh mt ngun pht cng sut

tc dng th khi cng sut pht cng gia tng s

ng ngha vi vic cng sut phn khng m

WP nhn v t h thng cng tng, iu ny s

gy gim in p cc nt ln cn v lm tng

nguy c mt n nh in p. Nh vy ch s L

thc cht l ch tiu ring nh gi mc n

nh in p nt nhng vn c th xem xt Nt

kt ni vi WP c ch s st p ln nht, k n

l cc nt kt ni my pht in tuabin gi vi

li in a phng. iu ny hon ton ph

hp thc t l: khi gia tng cng sut ti nt

PCC, lng cng sut phn khng m my pht

nhn t pha h thng tng ln [7, 8], cc nt

ln cn c nguy c b gim thp in p. c

bit nguy him khi c s c ngn mch ti nt

thanh ci 22 kV, in p ti y s b suy gim

mnh, lm mt cn bng cng sut phn khng

trong WP, nu khng c gii php ngn chn s

dn n sp in p.

5. KT LUN

Bi bo phn tch cc ch tiu nh gi

n nh in p trong h thng cung cp in,

t la chn ch tiu trong trng hp h

thng cung cp in c cc ngun in gi

tham gia. Vi cc ch tiu la chn ny cho

php xc nh c cc nt yu, nhnh yu

trong h thng in c kt ni nh my in

gi s dng loi my pht khng ng b v

xut cc bin php nng cao n nh in p.

Cc WP cng sut ln khi kt ni h thng

in, trong qu trnh vn hnh c gy nh

hng nht nh n n nh in p ca li

in. Vic mt n nh in p ca chng c

th gy nh hng n mt s nt ln cn. Vic

ng dng cc tiu chun n nh in p nt

nh gi mc n nh ca h thng in c

kt ni ngun in gi ng vai tr quan trng

trong qu trnh thit k, ci to hay quy hoch

mng in, trong c cc khu yu cn quan

tm: cc nt kt ni (PCC), cc nhnh c ni

vi nh my....Gii php b cng sut phn

khng lun c ch trng b vo phn

cng sut m WP nhn v t pha h thng,

gp phn nng cao cht lng in p.


Trang 92

STUDY OF VOLTAGE COLLAPSE CHARACTIRISTICS IN GRID CONNECTED

WIND POWER PLANT

Trinh Trong Chuong

HaNoi University of Industry

ABSTRACT: The scale of wind power plants is increasing continuously in Vietnam. The

installed capacity of the largest wind farm is about 50MW by the end of this year. Therefore, power

system planners will need to study their impact onthe power system in more detail. Wind energy

conversion systems are very different in nature from conventional generators. Therefore dynamic

studies must be addressed in order to integrate wind power into the power system. The impact of this

wind power on voltage distribution levels has been addressed in the literatures. The majority of this

work deals with the determination of the maximum active and reactive power that is possible to be

connected on a system load bus, until the voltage at that bus reaches the voltage collapse point. This

article introduces the methods of research standards, evaluation criteria of stable electricity supply; it

identifies the centers of loads and focuses on the branch is "weak" in small signal stability to improve

operational efficiency, reliability in electricity power supply.

Key words: voltage collapse, wind power, small signal stability

TI LIU THAM KHO

[1]. P. Kessel; Estimating the Voltage

Stability of a Power System; IEEE

Transactions on Power Delivery, Vol.1,

No. 3, July (1986).

[2]. Stefan Johansson; Voltage collapse in

power systems-The influence of generator

current limiter, on-load tap-changers and

load dynamics; Licentiate thesis Chalmers

University of Technology (1995).

[3]. I.A. Hiskens; Voltage stability

enhancement via model predictive control

of load; Intelligent Automation and Soft

Computing, Vol. 12, No. X, pp. 1-8,

(2006).

[4]. Feasibility Assessment and Capacity

Building for Wind Energy Development in

Cambodia, Philippines and Vietnam;

RIS - November (2006).

[5]. J.G. Slootweg; Wind Power:

Modelling and Impact on Power System

Dynamics; PhD thesis ; Technische

Universiteit Delft; (2003).

[6]. Bekob B.A; epexoe ekmpom exahueckue npoecc

ekmpueckux cuctemax; Bea

koa, Mockba, (1981).

[7]. Trinh Trong Chuong; Power quality

Investigation of Grid connected Wind

turbines; GMSARN International Journal;

No 3 (2009), pp 1 - 6.


Trang 93

[8]. Trinh Trong Chuong; Voltage quality

Improving of Phuoc Ninh (Vietnam) Wind

farm by using Static Synchronous

Compensator; The International

Conference on Electrical Engineering

2008, No. O-055.


Trang 94

MC LC CC CNG TRNH NGHIN CU

Trang Phm Vn Trung

V Vn Cng

L Khnh in

Nguyn Vn Nang

Phan nh Tun

Nguyn Thanh Nam

Nghin cu kh nng bin dng ca tm composite nn nha

nhit do khi gia cng bng SPIF

5

Phan nh Tun

Nguyn Thin Bnh

L Khnh in

Phm Hong Phng

ng dng cng ngh ISF gia cng mu chi tit v t

13

Nguyn Thnh Huy

o c Cng

V Thanh Thu

Bi T An

Hp cht siu dn st t UCoGe

21

Nguyn Hu Niu

Phan Thanh Bnh

Hunh Su

Tnh cht c hc ca compozit nn nha polypropylen c

gia cng bng si da (Sisal) Vit Nam

29

inh c Anh V

Paid - mt khung sn cho vic thit k v m phng vi

mch bt ng b

37

Phm Trn V

Biu din v so snh ng h s c nhn trong cc mng

khoa hc

46

Trn Ngc Thnh So trng mu da trn Cuckoo Hashing ng dng cho Nids 53

Hunh Hu Lc

Lu Quc Hi

inh c Anh V

Nhn dng ch vit tay dng rt trch thng tin theo chiu v

mng nron

62

Dng Tun Anh Tng quan v tm kim tng t trn d liu chui thi gian 71

Trnh Trng Chng

Nghin cu cc c trng sp in p trong li in c

kt ni nh my in gi 80


Trang 95

CONTENTS Page

Pham Van Trung

Vo Van Cuong

Le Khanh Dien

Nguyen Van Nang

Phan Dinh Tuan

Nguyen Thanh Nam

Deformation ability of single point incremental forming for

themo-plastic composite materials

5

Phan Dinh Tuan

Nguyen Thien Binh

Le Khanh Dien

Pham Hoang Phuong

Applying the ISF technology to produce the car part models

13

Nguyen Thanh Huy

Dao Duc Cuong

Vu Thanh Thu

Bui Tu An

On discovery of the ferromagnetic superconductor UCoGe

21

Nguyen Huu Nieu

Phan Thanh Binh

Huynh Sau

Mechanical properties of the Viet Nam sisal fibre reinforced

polypropylene composite

29

Dinh Duc Anh Vu

PAID A novel framework for design and simulation of

asynchronous circuits

37

Pham Tran Vu Dynamic profile representation and matching in distributed

scientific networks

46

Tran Ngoc Thinh CPM: Cuckoo-based pattern matching applied for NIDs 53

Huynh Huu Loc

Luu Quoc Hai

Dinh Duc Anh Vu

Modified direction feature and neural network based

technique for handwriting character recognition

62

Duong Tuan Anh An overview of similarity search in time series data 71

Trinh Trong Chuong

Study of voltage collapse charactiristics in grid connected

wind power plant

80

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