Extras din proiect
Sa se analizeze stabilitatea la mici perturbati si stabilitatea tranzitorie pentru sistemul electroenergetic cu trei noduri sistem a carui schema e data in figura de mai jos:
Fig.1 Schema monofiara a SEE cu 3 noduri studiat
Fig.2 Schema echivalenta monofazata a SEE cu 3 noduri analizat
Etapa I
Calculul marimilor relative a parametrilor de retea si a marimilor de stare
Se alege o marime de baza si anume puterea aparenta :Sb=660MVA, iar tensiunea de baza se alege pentru fiecare treapta de tensiune astfel:
Ubg=Ub1=24KV;
Ub2=Ub3=400KV;
• Relatiile de calcul a parametrilor de retea in marimi relative:
• Relatiile de calcul a marimilor de stare in unitati relative:
• Relatia si modul de calcul a tensiunii electromotoare in unitati relative:
unde :
in care: Xd=207%
Sng=776.47MVA
• Relatiile de calcul a admitantelor transversale in unitati relative :
unde Ys=Pc1-jQc1/U12 admitanta sarcinii;
Program in Matlab:
j=sqrt(-1);
Ub1=24;
Ub2=400;
Ub3=400;
Sb=660;
Xd=207;
Pg=660;
Pg1=528;
Qg=50;
cosfig=0.85;
Pc1=45;
Qc1=33.75;
y11=0.13944724- j*9.14089023;
y22= 0.00388189 -j*0.06548073;
y33= 0.00338425 -j* 0.03165603;
y12=0.00829392 - j*0.54812011;
y21=y12;
y23= 0.00338425-j*0.03233623;
y32=y23;
u1=24;
u2=399.9562;
u3=400;
U1=u1/Ub1
U1complex=U1*(cos(0.1822)+j*sin(0.1822))
U2=u2/Ub2
U2complex=U2*(cos(0.0902)+j*sin(0.0902))
U3=u3/Ub3
Sng=Pg/cosfig;
Xg=(Xd/100)*(Sb/Sng);
Y11=y11*Ub1^2/Sb
Y22=y22*Ub2^2/Sb
Y33=y33*Ub3^2/Sb
Y12=y12*Ub1*Ub2/Sb
Y21=Y12;
Y23=y23*Ub2*Ub3/Sb
Y32=Y23;
ys=(Pc1-j*Qc1)/24^2;
Ys=ys*Ub1^2/Sb;
Y10=Y11-Y12+Ys
Y20=Y22-Y21-Y23
Y30=Y33-Y32;
Pgur=Pg1/Sb
Qgur=Qg/Sb
Ig=(Pg2-j*Qg2)/conj(U1)
E=U1+j*Xg*Ig
In urma executiei programului in matlab obtinem urmatoarele rezultate:
- Marimile de stare in u.r
U1 =1
U1complex =0.9834 + 0.1812i
U2 = 0.9999
U2complex =0.9958 + 0.0901i
U3 =1
Pgur =0.8000
Qgur =0.0758
- Parametri de retea in u.r
Y11 =0.1217 - 7.9775i
Y22 =0.9411 -15.8741i
Y33 =0.8204 - 7.6742i
Y12 =0.1206 - 7.9727i
Y23 =0.8204 - 7.8391i
Preview document
Conținut arhivă zip
- Sisteme Electrice.doc