, 2004.
1: : Sn=31,5 MVA; mt =121/10 kV/kV; Pcu=200 kW ( ); Pfe = 86 kW ( ); uk=10,5%; io=2,7%. , . : ) ; b) . : Ip Ztp Iop Up Ytp Usp Up Isp Ip Iop Ytp Usp Ztp Isp
*) Ip Zp Iop Up Ytp Usp Zsp Isp
**) Ztp- , Ytp- , Zp- , Zsp- . ***)
: *) , **) , ***) . ( ) . : , :
1
Y t = G Fe jB =Yt jX RFe
1 1 j ; RFe X2 100 U n . I o (%) S n
RFe =
2 Un , PFe
X =
Zt , ( ) .Zt Rt U Rt = Pcu n S n , 2
jXt
Z t = Rt + jX t ;
2 u (%) U n ; Zt = k 100 S n
X t = Z t2 Rt2 .
(Un=Unp) . (Un=Uns) . ( ). , , : Z p Z sp = Z tp 2 , Z s Z ps =Z ts . 2
e . .
Un (kV) a) 121 10 b)
RFe () 170244 1162,8
GFe (S) 5,87410-6 8,610-4
X () 17214,6 117,58
B (S) 5,8110-5 8,510-3
Rt () 2,95 0,0201
Xt () 48,8 0,333
2
2: Sn =1 MVA; mt =10/0,4 (kV/kV); i0 =1,4 %; uk =5,5 % :) ; ) ; ) 50% .
: . (a) . , ( ). . . , . . , .
Ip
j Xt
Isp
Xt - ( + ), Rt - , X - ,
j X Up Iop
RfeUsp
Rfe - ( ). , , .
) (Isp=0) (Q0) ( ).2 I (%) I Un 1,4 = 3U n I 0 = 3U n I n 0 = S n I o (r. j ) = S n 0 = 1 = 0,014 Mvar. 100 In 100 X
Q0 =
3
b) , (Q0), (Q) , Xt . (Qpn) :2 Q pn = 3 X t I n = 3 X t 2 2 I nU n
U
2 n
= Xt
2 Sn
U
2 n
= Xt
Sn U2 n
Sn =
Xt x (%) S n = X t (r. j.) S n = t Sn . 100 Z baz
(xt(%)) (uk(%)) :u k (%) = Uk 100 = Un 3Z k I n Z S Z 100 = k 2 n 100 = k 100 = z k (%) = Rt (%) 2 + X t (%) 2 X t (%) Un Z baz Un
(Qpn) .Q pn = u k (%) 5,5 = 0,055 Mvar . S n = 1 100 100
(Qn) :
Qn = Q0 + Q pn = 0,014 + 0,055 = 0,069 Mvar .
c) , (Qp) :
Qp = 3X t I 2 = 3X t (
u (%) I 2 I n ) 2 = 3 X t 2 I n = 2 Q pn = 2 k Sn , 100 InI ). In
I ( = S =0,5Sn (Q50%) :Q 50% = Q o + Q p 50% = S n
i 0 (%) u (%) 5,5 1,4 + 2Sn k = 1 + 0,5 2 = 0,02775 Mvar. 100 100 100 100
50% - 40,22% .
4
400 (kV / kV ) , 220 xt = 10% , S n = 400 MVA , x . =320 MW - I II . I U1 = 400 kV. P=320 MW U =? U1= 400 kV 2 U2 II I II - I, Q2=0. Q2=? .
3:
: mt =
: x , . . .
P1=P Q1=Q U1
jXt
P2=P Q2=0 U2p=U2p 0 0
U2p II .
Q
- (, ) , . , . U1 U2p , , I Xt ( II ). , U1 U2p I II. :
S 1 = P1 + jQ1 = 3U 1 I ; P1 = P,
*
Q1 = Q = 3 X t I 2 .P3 U2p2 1
S 2 = P2 = P = 3 U 2 p I I = I =
.
S1 S 1 = P + Q = 3 U 1 I2 2
P2 P2 U = P2 + X t 2 2 U U2p 2p
2
5
:4 2 U 2 p U 12U 2 p + X t2 P 2 = 0.
. : Ubaz=U1=400 kV Sbaz=Snt=400 MVA. :4 2 u 2 p 1 u 2 p + 0,12 0,8 2 = 0
4 2 u 2 p u 2 p + 0,0064 = 0.
: u 2 p = 0,99356 r. j. , :U 2 p = u 2 p U baz = 0,99356 400 = 397,42 kV .
II :
U2 =
U2p mt
=
397,42 220 = 218,58 kV . 400
U2 220 kV> U2> 218,58 kV, () II, I. U2 U2=220 kV I II.
6
4: , , B, ( ). Yd5, (Uab, Ubc, Uca) A c . UA UB B a : Yd5; Sn = 4 MVA; mt = 35/10,5 (kV/kV); Io(%) = 1%; UC C b Xt(%) = 8%. . : , 300 , . 5, 5300=1500. , Yd5 . . UA
UbcUb
Uc 150o Ua
Uca
mt Uca 3 m UB = t Uab 3 m UC = t Ubc 3UA =
Uab UC
UB
, , ( D , y ). . ( ) , Yd5. Yd5.
7
AUA UB
c a b
B C
UC
( ) B. , () ( ) . :
UB =A
35 3
kV 0 0
B
C
uB = N p
c
/2
a
b
/2
d d ( / 2) ; u A = uC = N P . dt dt d d ( / 2) uab = N s ; uca = ubc = N s . dt dt u u B N p mt ; u bc = u ca = ab . = = 2 u ab N s 33 UB = mt 3 10,5 35 = 10,5 kV 35 3
U ab =
U ca = U bc =
U ab 10,5 = = 5,25kV . 2 2
, , .
8
5: , Sn=4 MVA; mt=35/10(kV/kV); Io(%)=1%; Xt(%)=10%; Yd9 , . () : ) ; b) () (); c) (). .UA UC UB PA PB PC B A C c b a
: ) , :I 0 A = I 0 B = I 0C = I 0 = I 0 (%) I (%) S n 1 4000 In = 0 = = 0,67 A . 100 100 3U n 100 3 35
b) , . . U b B C , I A0 A , I b A0 , Ua, :c
A = N p = N p
N pI e
b A0
= Np
N pI3 2
b A0
=
2N I 3
2 p
b A0
b
/2
a
/2
. : N p - ,
, - ( ). 2 Np , L =
9
b (I0) ( I A0 ). :
UA =
Un3
= A =
2 N p I0
= L I 0 .
:2 b 2 N p I A0 2 b UA = = A = = L I A 0 . 3 3 3
Un
b , I A0 I0, . :
b I a0 =
3 I 0 = 1,5 0,67 = 1A . 2
c) , . . UC U A B C c c I 0C I 0A .I n 0 = I 0 A + I 0Cc c
c
A
b
A+C
a
C
( ).A UA C UC 1 N p I 0C 2 N p c 1 c ( I 0 A I 0C ) = AA AC = 3 = 3 2 2 3 2 2 2 2 Np c 1 c 2 1 c c ( I 0 A I 0C ) = j L ( I 0 A I 0C ) = j N p A = j 3 2 3 2 c c N p I 0C 1 N p I 0 A 2 N p c 1 c ( I 0C I 0 A ) = CC CA = 3 = 3 2 2 3 2 2 2 2 Np c 1 c 2 1 c c ( I 0C I 0 A ) = j L ( I 0C I 0 A ) = j N p C = j 3 2 3 2 N p I 0Ac c
10
UA UC :
I 0A = j
c
2U A + U C
L
=j
U A U B
L
=j
U AB
L ;
I 0C = jc
U U B 2U C + U A U =j C = j BC ; L L L
:
I 0 n = I oA + I oC = 3
c
c
U A +U C U = j3 B . j L L
B C :
I 0 A = I 0C =c c
Un = 3 I 0 = 3 0,67 = 1,16 A L
:
I 0n = 3
U nf
L
= 3 I 0 = 3 0,67 = 2,01 A
.
UA
I0n I 0C I 0Ac c
UC
U
11
6: Dy, Sn=100 MVA, mt=110/10 (kV/kV) io= 0,5%. A UA UB B Dy11, U C C , .
:A 1 Dy11. . , , ( ). 2.
a UCAUa
UA
UAB330o Ub
UC
b cUc UB
C UBC 1
B
A UA UC UB B C
b c
2
3 , , 3.I0 A
I0 B I0 C
3
12
4 5: A
B
110kV I0BC
C
A IA I0AB B UBC C IB IC=IA
IB IA
B
IA=IC
4 a b 5 5 ( B): c n
B = BB + BA + BC , - IB , : N pIB3 2
BB =
, :
N p - , - ( ). , . , (), , :
BA = BC =
1 N pIA . 2 3 2
:
13
2 2 2 Np Np 1 N pIA B = N p B = 3 +2 = ( I A + I B ) 3 = I 0 BC 3 . 2 3 2 2 2 2
2 N pIB
Un, :
U n = B =
2 Np 3 2
I 0 BC I 0 BC =
Un
2 Np 3 2
( 3) : I0 = I o (%) I (%) S n 0,5 100 10 3 In = o = = 2,624 A , 100 100 3U n 100 3110
( ) :
I0
2 Np Un Un 3U n = = L = = . 2 I 0 Np 3 L
:I 0 BC = Un = Un 2 3U n 3 I 0 = 3 2 3 I 0 = 0,866 I 0 = 0,866 2,624 = 2,27 A .
N3 2
2 p
14
7: : Dy, 630 kVA, mt=10/0,4 (kV/kV) . : sprega ; Un=0,4 kV; Pn=160 kW. 0,4 kV, , , . . A UA UC UB B C b cR R R
: , ( ):2 2 3U n 3 0,4 2 Un R= = = 3 . Pn = 3 0,16 R Pn
10 kV 0,4 kV :Ia = Ib = Ic = Pn 160 10 3 = = 230 , 94 A ; 3U n 3 400
I A = I B = IC =
I c 0,4 = 230,94 = 9,238 A . mt 10
a , b c ( ), , , Ubc, :N IA=I A UA UC UB IB=I B IC=2I C 0 I I I I N Ia=0 b Ib=I c Ic=I Ubc R R R
I 2R R, :
15
Re =
2R R 63 = = 2 . 2R + R 6 + 3
b c , b c:
I"=
U bc 400 = = 200 A, I b = I c = I " = 200 A, I a = 0 A. Re 2
, , .: N ' I ' = N " I " . , . , :
I'=
1 N" 1 0,4 I"= I"= 200 = 4,619 A . N' 3 mt 3 10
. , , 10 kV , 0,4 kV :
I A = I ' = 4,619 A,
I B = I ' = 4,619 A I C = 2 I ' = 2 4,619 = 9,238 A .
, , .
16
8: . 35 X c IA , ako je U= kV , X=1 . C 3 b : B X Snt=4 MVA; mt=35/10 (kV/kV); xt=10% . A X IA=? U : . .IC=0 C IB=0 B A U IA=? Ic=0 Ic=0 Ia Ia
