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Làm việc song song của các máy phát điện đồng bộ có đặc tính khác nhau trong trạm phát điện tàu thủy
Làm việc song song của các máy phát điện đồng bộ có đặc tính khác nhau trong trạm phát điện tàu thủy
VCCA-2011
Lm vic song song ca cc my pht in ng b c c tnh khc nhau
trong trm pht in tu thy
Parallel working of synchronous generators having different characterictics
in shipboard
s power station
Nguyn Tin Ban
Trng H Hi Phng
e-Mail: bannguyentien@gmail.com
Tm tt
Li in tu thy l li mm vi cng sut ca
trm pht xp x bng cng sut ph ti, in p v
tn s lun thay i trong qu trnh vn hnh v
khai thc. Trm pht in tu thy thng c
thit k cc cm Diesel Generator (DG) ging ht
nhau v cng sut, c tnh vi mc ch chn c
di rng cho vng lm vic song song trn c tnh
ra, p ng kh nng n nh cho trm trong qu
trnh vn hnh khai thc. Bi bo trnh by vic
nghin cu cc i tng my pht ng b c
cng sut v c tnh ra khc nhau c a vo
lm vic song song trong trm pht in tu thy
cung cp nng lng lu di trong cc ch khai
thc. y l vn k thut kh khn m vic gii
quyt thnh cng s mang li tnh k thut, tnh
kinh t cng nh p ng tnh khai thc an ton
hng hi m Hip hi Hng hi IMO i hi ngy
cng kht khe hn.
Abstract:
The grid on ship is a soft grid, whose capacity is
approximately equal to the capacity of loads, and its
voltage and frequency are varied during the
operation time. Conventionally, groups of Diesel
Generator machines (D-G) with identical capacities
and characteristics are often used in power-station
on ship in order to achieve a large working range
on the load characteristic curve, so that the system
is stabilized. This paper presents a research on
utilizing generators with different characteristics
and capacities working in parallel in power-station
on ship to supply stable power in different working
modes, which is a difficult technical problem.
Successfully solving this problem can bring
technical and economic benefits, as well as satisfy
the strict safety requirements of International
Maritime Organization (IMO).
K hiu
K hiu n v ngha
rad/s tc gc
Gc pha vng quay my
T
net
Nm Moment tng ca my
T
mech
Nm Moment do D to nn
T
elec
Nm Moment in t
P
net
W Cng sut tng
P
mech
W Cng sut c
P
elec
W Cng sut in
J Moment qun tnh
M Nm Moment ng ca my
e A
thay i vng quay
tng i.
q
Lng nhin liu vo D
Ch vit tt
DG Diesel - Generator
M-S Master - Slave
MIMO multi input multi output
M u
Cho n tn thi im hin nay, cc cm DG trong
cc trm pht in tu thy lun c la chn c
cng sut v c tnh bng v ging nhau hon
ton. Cc ng c s cp l diesel lun chn cng
cng sut, cng series ca cng hng, my pht
cng vy. Thc cht l ngi ta mong mun chng
ging nhau nh hai git nc c c mt
vng c tnh cng sut ra tng i ca h trng
kht ln nhau, to nn di lm vic n nh cho trm
trong iu kin ti thay i rt ln (v cng sut v
tnh cht ti). Vi cu trc ca trm nh vy, trong
qu trnh khai thc gp rt nhiu kh khn v tu
thy vi nm ch hot ng, cc ch ny c
tnh ti khc nhau rt ln, s xy ra tnh trng ch
ny my pht gn nh chy khng ti nhng
ch khc th trm li qu ti. Vi cc tu cng
sut trm nh v va, lng chnh lch trong cc
ch khai thc mt my cn c th chp nhn,
nhng tu cng sut ln th iu ny dn n vic
lng ph nhin liu, my mc (b mi mn, gi ci..)
v nhim mi trng rt ln. Mt khc, trn tu
thy, ngoi trm pht chnh, ngi ta cn trang b
cc trm pht d phng, trm pht cng, trm s
c cng sut v c tnh hon ton khc vi trm
pht chnh, m y li l nhng i tng cn v
rt cn kt ni v lm vic song song vi nhau.
Nh vy, khi to nn kh nng lm vic song song
gia cc my c cng sut v c tnh rt khc nhau
thnh cng s m ra mt kh nng ng dng rt
ln, mang li li ch khng nh cho ngnh Hng
hi, ngnh ng tu v cc trm pht a phng c
606
Hi ngh ton quc v iu khin v T ng ho - VCCA-2011
VCCA-2011
tnh cht ging vi li in mm nh trn tu
thy.
Phn chia cng sut trong trm pht
in tu thy
2.1 C s ca vic phn chia cng sut
Cng nh phn tch trn c tnh ngoi U = f (I) ,
khi cc my lm vic song song vi nhau, ng
biu din quan h gia tn s v cng sut tc dng
f = f (P) lun tn ti h s sai tnh k
c
(
o tg k
C
=
).
Nh vy s thay i tn s:
P k f
C
. = A
( 1)
Du (-) trong phng trnh (1) biu th s thay i
ngc nhau ca P v f (cng sut tng th tn s
gim v ngc li). C th vit (1) nh sau:
0 . = A + f P k
C
(2
)
Vit theo n v tng i:
0 .
* *
= A + A f p k
C
(3)
Trong :
;
*
dm
P
P
p
A
= A
dm
f
f
f
A
= A
*
Vit li (3) thnh:
C
k
f
p
*
*
A
= A
(4)
Qua (4) thy rng, nu cho c tnh ca mt my
pht c h s sai tnh k
C
= 0.04; f
*
= 0.01 th ti
s dao ng trong khong p
*
= -1/4 = - 0.25 tc l
dao ng cng sut khong 25%. Nh vy, ch cn
tn s dao ng 1% th cng sut dao ng 25%
trong khi quy phm quy nh chnh lch ti
cho php gia hai my khi lm vic song song
trong phm vi 10%.
Mt trong nhng yu cu t ra khi phn phi cng
sut tc dng l phi m bo ch tiu kinh t,
tiu hao nhin liu c t ra l tit kim nht.
Vi diesel, mi mt my c mt c tnh tiu hao
nhin liu G = f (P) khc nhau ( G: lng nhin
liu tiu hao theo thi gian, cn P l cng sut).
t yu cu v tiu hao nhin liu cn tha mn:
n
n
dP
dG
dP
dG
dP
dG
dP
dG
= = = = ...
3
3
2
2
1
1 (5)
nh gi qua cng sut tc dng:
ndm
n
dm dm dm
P
P
P
P
P
P
P
P
...
3
3
2
2
1
1
= = =
(6)
Cng nh cng sut khng, cng sut tc dng
c thc hin phn phi theo c tnh tnh. Gi s
c ba my pht cng lm vic song song vi c
tnh f = f (P) nh hnh 1, lc u cc my lm vic
vi tn s f
1
ng vi cng sut mi my P
1
,P
2
, P
3
, .
Khi tng ti cho trm, v c sai s nn tn s ca
li s n nh ti f
2
v dao ng cng sut P
1
,
P
2
, P
3.
.
T th thy rng:
1 1
1
c
k
f
tg
f
P
A
=
A
= A
o
2 2
2
c
k
f
tg
f
P
A
=
A
= A
o
(7)
3 3
3
c
k
f
tg
f
P
A
=
A
= A
o
Tng qut:
Ci
i
k
f
P
A
= A
(8)
Tng s cng sut dao ng trong khong dao ng
tn s f:
=
A = A + + A + A + A
n
n
n n
P P P P P
1
3 2 1
...
(9)
)
1
...
1 1
(
2 1 1 Cn C C
n
i
n
k k k
f P + + + A = A
=
(10)
)
1
...
1 1
(
2 1
1
Cn C C
n
i
i
k k k
P
f
+ + +
A
= A
=
(11)
Nh vy :
)
1
...
1 1
(
2 1
1
1
1
Cn C C
C
n
i
i
k k k
k
P
P
+ + +
A
= A
)
1
...
1 1
(
2 1
2
1
2
Cn C C
C
n
i
i
k k k
k
P
P
+ + +
A
= A
(12)
)
1
...
1 1
(
2 1
1
Cn C C
Cn
n
i
i
n
k k k
k
P
P
+ + +
A
= A
Trong :
=
A
n
i
i
P
1
l tng gia s ti ca trm pht
n y c th vit quy lut iu chnh cng sut
tc dng nh sau:
=
= + A
n
i
i C
P P k f
1
1 1 1
; 0 ) ( o
=
= + A
n
i
i C
P P k f
1
2 2 2
; 0 ) ( o
(13)
Hnh 1 C s ca vic phn chia
cng sut tcdng cho cc my khi
lm vic song song
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Hi ngh ton quc v iu khin v T ng ho - VCCA-2011
VCCA-2011
=
= + A
n
i
i n n Cn
P P k f
1
. 0 ) ( o
Vi
1 ...
3 2 1
= + + + +
n
o o o o
(14)
Mt s nhn xt:
Cng sut dao ng ca tng my pht ph thuc
vo tng s cng sut dao dng ca ton trm pht,
Cng sut dao ng ca mi my pht t l nghch
vi h s sai tnh ca n,
H s sai tnh ca mt my pht bng 0 th my
nhn ton ti ca trm, cn nu h s sai tnh ca
tt c cc my pht u bng 0 ( = 0) th h l h
v sai, trng hp ny h khng c kh nng lm
vic c v cc my nhn ti khng n nh.
2.2 Phn chia cng sut cho cc my khc c
tnh trn trm pht in tu thy
Vi my pht ng b khi lm vic song song, vic
phn chia cng sut phi thc hin can thip vo
hai thnh phn: Phn chia cng sut khng Q v
cng sut tc dng P.
2.2.1 Phn chia cng sut khng Q
Cng sut khng Q phi can thip vo dng kch t
ca my pht, nu khng gii quyt tt vic phn
chia Q, dng phn khng s c nh hng ln n
qu trnh lm vic ca h khi ng b, s xut hin
dng cn bng rt ln ( c th ln hn dng nh
mc rt nhiu) trong khi dng ti li rt nh. Vi
vic phn chia Q trong [1] ch ra nhiu phng n
trong trong trng hp lm vic gia cc my
khc c tnh m bi bo ang t vn s la
chn phng n can thip vo dc ca c tnh
tnh.
Hnh 2 thc hin vic to dc cho c tnh ngoi
trn c s phn hi t dng ti ly trn in tr
CCR hnh 2.a. Nh vy, khi dng ti cng tng
hoc cos cng gim ( in p trn cc my pht
cng st ln) th in p U
o
cng ln hnh 2.b lc
dng kch t cng tng tng in p ln ln.
Hnh 3 trnh by vic to dc bng vic thay i
in tr CCR.
2.2.2 Phn chia cng sut tc dng P
Hin nay, b iu tc ca cc diesel lai my pht
c rt nhiu thay i so vi nhng b iu tc s
dng cho cc h DG trc y, cc hng ln
khng cn qu l thuc vo nhng b iu chnh
tc c hc hoc cc b lai gia b iu tc c
hc v in t nh cc h c sn xut thp nin
cui ca th k 20. iu ny cho php thc hin
iu khin cc h DG theo yu cu ph ti ch
khng cn nm trong gii hn iu chnh na v v
th v vic to nn cc c tnh f = f (P) c nhng
thun li hn cho vic ghp ni cc h DG c
nhng tnh cht khc bit nhau lm vic vi nhau
trong h. Tuy nhin, ct li ca kh nng nhn ti
ca cc diesel chnh l kh nng sinh cng ca tng
xilan trong mt my m iu c bit cn thit l
cc xilan phi to nn tc ng trn trc
khuu vi cc lc c hc u nhau cc
chu k sinh cng ca mnh, c nh vy
th kh nng n nh ca h mi c
m bo. Bi bo vit trong phm vi
iu khin h thng vi mi vn v
c hc coi nh c gii quyt trn
vn v k thut. thc hin ha cc
my pht c cc c tnh khc nhau lm
vic cng nhau trong li mm, [1]
ch ra nhiu phng php, tuy nhin phng php
Master Slave ( M-S) l ph hp hn c. Ni dung
ca phng php M-S tm tt nh sau: dng mt
my lm ch (Master) cc my cn li ng vai tr
t (slave). Tnh tin c tnh ca cc slave theo
master ti im lm vic ng vi cng sut mi P
2
.
Phng php ny cn la chn my ch phi c c
tnh ngoi cng trong trng hp ny phi chn
Hnh 4 C s ca vic phn chia cng sut tc
dng cho cc my khi theo phng php
M S
Hnh 2 To dc cho c tnh ngoi
thng qua tn hiu dng ti
Hnh 3 To nn dc khc nhau
nh iu chnh in tr CCR
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Hi ngh ton quc v iu khin v T ng ho - VCCA-2011
VCCA-2011
my c cng sut ln v c sai s tc nh hn.
Hnh 4 trnh by vic dch c tnh theo phng
php ny. y, tn s ca li cng s b thay i
f
2
gim i so vi im f
1
(khi ti cn nh) v vy
cn iu khin sao cho vic gim tn s phi
nm trong phm vi cho php. Thc cht ca
phng php l thay i tham s cho b iu tc
nh tc ng ti servo motor v y cng chnh l
kh nng can thip ca ngi iu khin. Thc ra,
do vic iu chnh theo cc phng php kinh in
trc y thc hin tch knh gia iu chnh tc
v iu chnh in p nn trong vic iu chnh
tc thng thc hin thun ty theo lch vi
cc b iu tc c hc v iu ny thng c nhc
im l chnh xc khng cao, lun tn ti sai
lch tnh ln, h thng tc ng chm, kh nng
cng kch cha hiu qu v nu cc h DG c c
tnh khc nhau th khng lm vic vi nhau c,
lun xy ra cp ti, cng sut ngc v b sa thi
ra khi li.
2.2.3 Xy dng m hnh h thng
Hnh 5 xut m hnh lm vic song song cc
my pht c c tnh khc nhau trong trm pht tu
thy theo phng n M S vi c tnh quan h
gia tn s v cng sut f = f (P) v c tnh ngoi
ca my pht U = f (I). p ng c kh nng
iu khin cc my pht h thng c c tnh cng
sut rt khc nhau. S chc nng c xy dng
hnh 6 trn li ca trm lc c No1.DG v
No2 DG lm vic vi nhau. M hnh ton ca h
c vit:
Quan h gia cng sut in v c trong h DG :
) ( ) ( ) ( t P t P t P
Elec Mech net
= A
(15)
V cng sut:
) ( ) (
0
t P P t P
net net net
A + =
(16)
Trong :
0 0 0 Elec Mech net
P P P =
(17)
Vit li:
)] ( ) ( [ ) ( ) (
0 0
t P t P P P t P
Elec Mech Elec Mech net
A A + =
(18)
Cng sut quan h vi moment:
) ( ) ( ( ) ( ) (
0
t T t T t P t P
Elec Mech Elec Mech
A A = A A e
(19)
Khi tc gc thay i, cng sut c th tnh c:
)] ( )].[ ( [ ) ( ) (
0 0 0
t T T t t P P t P
net net net net net
A + A + = A + = e e
(20)
Phng trnh chuyn ng:
dt
d
J T T T T
Elec Mech Elec Mech
) (
) ( ) (
0 0
e A
= A A +
(21)
Phng trnh vit cho diesel c b iu chnh tc
:
elec d d d
P K
dt
d
T A = A +
A
u q e
e) (
(22)
M hnh ton my pht ng b:
q
d
b
d d
dt
d
I R U e
e
. .
1
. + =
(23)
d
q
b
q q
dt
d
I R U e
e
. .
1
. + + =
(24)
dt
d
T I
D
D D
. 0 + =
(25)
dt
d
T I
Q
Q Q
. 0 + =
(26)
D d d kt d
I I x i + =
(27)
Q q q q
I I x + = .
(28)
D d d d kt kt
I g I x i . .
1
+ =
(29)
d d d kt D D
I x i g I . .
2
+ =
(30)
q q q Q Q
I x I . + =
(31)
M hnh ton b iu chnh in p
KD kt U
I
d I U q U q I U d U
I U
I U
kt
K E i x I K x U K I K x U K
x x
x
u
A
(
+ +
+
=
2
1
2
2
2 2
1
) ( ) (
|
|
(32)
) (
1
N
U U
Tp
K
E
+
= A
(33)
Hnh 5 H thng phn chia cng sut cho cc my c c tnh khc nhau
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Hi ngh ton quc v iu khin v T ng ho - VCCA-2011
VCCA-2011
Mch vng iu khin tc c xy dng
nh hnh 6, vi tn hiu t c ly t b tnh ton
cng sut.
M hnh h thng vi hai my pht lm vic song
song trong li thng qua vic ghp ni trn thanh
ci ( bus bar) ca bng in chnh ( MSB) trong
trm pht in tu thy c xy dng nh hnh 7.
Mch iu chnh tc nhn di dng hm truyn
c xy dng nh trn hnh 8.
T m hnh h thng, xy dng cc b iu khin
theo chun mun ti u, s dng phn mm m
phng Matlab Simulink nghin cu mt s trng
thi in hnh trong h. Kt qu nhn c ng
cong cng sut nh trn cc kt qu ca th tc
thi trn cc hnh 9, 10 v 11.
Hnh 9 m phng h cho hai my nhn 38% cng
sut ca mi my. c tnh nhn c trn h trc
tng i thy rng h phn ng rt tt. Ti giy
m phng th 5, cc my cng cho nhn khong
38% ti (cng sut) nh mc trong my c cng
sut ln ng vai tr Master cn my cng sut nh
ng vai tr Slave, c hai my sau nhng dao ng
qu th n nh vi gi tr ti t. Master c
qu chnh ln hn Slave, iu ny cng hon
ton ph hp vi tnh cht phn ng t nhin ca
h vi cc gi tr t v cc b iu khin
Hnh 10 l kt qu m phng h thng vi hai gi
tr cng sut t cho cc my, ti giy m phng
th nht, cho hai my nhn 38% cng sut mi my
nh phn m phng hnh 9, n giy th 11, cho
my nhn 77% cng sut mi my, kt qu cc
Master v Slave u phn ng kh tt vi gi tr t
v qu trnh qu cng din tin theo kt qu n
nh. Dao ng ca h c qu iu chnh, s ln
dao ng khong 4 chu k v thi gian qu
khong 4 s .
Hnh 11 l kt qu m phng h thng vi hai gi
tr cng sut t cho cc my l khc nhau trong
v my ch (M)c cng sut ln hn nn t gi tr
cao hn. bc m phng u t Master nhn
38% cn Slave nhn 29% cng sut. Thi gian
thc hin step 1 ti giy th nht, step 2 ti giy th
11, cho Master nhn 58% cn Slave cng sut nh
nhn 38%. Kt qu h phn ng cng rt tt vi cc
ch tiu k thut m bo tt trong phm vi yu cu
v k thut ca cc hng ng kim.
Hnh 8 Mch iu chnh tc ca h
Hnh 7 H thng hai my pht c c tnh
khc nhau lm vic song song trn li mm
Hnh 6 Mch vng iu khin tc Diesel
Hnh 9 c tnh qu ca hai my pht khi
nhn t l cng sut nh nhau
Hnh 10 c tnh qu ca hai my pht khi
nhn t l cng sut nh nhau v t phn chia
li khi nhn ti t ngt
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Hi ngh ton quc v iu khin v T ng ho - VCCA-2011
VCCA-2011
Kt lun
Nghin cu a cc my pht ng b c cc c
tnh ( rt) khc nhau vo lm vic song song trong
trm pht in tu thy l mt vic c t ra
kh lu vi cc nh k thut v cc cng ty c sn
phm k thut cung cp trong ngnh Hng hi.
Trc y, khi cc diesel lm vic vi cc b iu
tc kinh in th mong mun ny khng thc hin
c do tnh c th hn ch v kh nng iu
chnh cng nh hng s thi gian qu ln ca h
iu tc c hc.
Hin nay, cc vn k thut tr nn n gin
hn do bc tin ca ngnh cng ngh in t v
tin hc cng vi s pht trin rt ln trong cc
phng php iu khin t ng. Chnh iu kin
hin nay mi m ng cho kh nng tip cn
nhng d n v k thut kh, a dng v a chiu.
Bi bo xy dng m hnh iu khin trn c s
ton hc vi nhng kt qu kh quan. Trong thc
t, vic nghin cu a ra c cc sn phm t
l thuyt ny cn l mt vn khng n gin,
c bit vi c th Vit Nam. Tuy nhin thc
hin c mc tiu ny, tc gi cng cc ng s
c nhng bc nghin cu ng dng u tin v
vch ra tiu ch cng nh l trnh hin thc
ha sn phm. Thc cht y l mt sn phm s c
kh nng ng dng rt cao nu nh p ng c
ch tiu cht lng v cng ngh..
Ti liu tham kho
[1] Thn Ngc Hon; Nguyn Tin Ban.: Trm
pht v li in tu thy. Nh xut bn Khoa
hc v K thut, H Ni , 2008
[2] Nguyn Tin Ban.: iu khin trm pht in
tu thy. Tp ch KH CN Hng Hi, 2006
[3] DEIF: PPM Protection and Power
Management www. DEIF.com
Hnh 11 c tnh qu ca hai my pht khi
lm vic song song , nhn ti t ngt vi t l
cng sut khc nhau
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