1. A 34.64kV, 50MVa synchronous generator having a direct axis reactance of 13.
5Ω and
quadrature axis reactance of 9.33Ω is operating at 0.8 pf. Write a MATLAB program to
determine the excitation emf, regulation. Also plot the power angle curve. (Xd~=Xq)
Output:
Ef = 3.0000e+004
reg = 50.0024
2. A 34.64kV, 50MVa synchronous generator having a direct axis reactance of 10Ω and
quadrature axis reactance of 10Ω is operating at 0.8 pf. Write a MATLAB program to
determine the excitation emf, regulation. Also plot the power angle curve. (Xd=Xq)
Output:
Ef = 2.7203e+004
reg = 36.0171
3. Write a MATLAB program to calculate the Sag of a transmission line for: Poles at
unequal height using the given data:
Height of Tower A = 70 m
Height of Tower B = 95 m
Span length (L) = 400 m
Tension in the conductor (T) = 1100 kg
Weight of the conductor per unit length (w) = 0.8 kg/m
Output:
Sag at lower support (S1): 4.7310 m
Sag at higher support (S2): 29.7310 m
Distance from lower support to lowest point (x1): 114.0625 m
Distance from upper support to lowest point (x2): 285.9375 m
4. A 220kV 3Φ transmission line is 40km long. The resistance per phase is 0.15Ω/km and
inductance per phase is 1.3263mH/km. The shunt capacitance is negligible. Use short
transmission line model to find regulation and efficiency when line is supplying a 3Φ load
of 381MVA at 0.8 pf lagging at 220kV. Write a MATLAB code to calculate the
parameters.
Output:
Is =7.9989e+002 -5.9992e+002i
vsl = 2.4910e+005 +2.1478e+004i
eff = 94.4252
reg = 13.6462
5. Analyze the performance of a 300 km long transmission line using the rigorous method.
The line has a series impedance of (0.1 + j0.5) Ω/km and a shunt admittance of j0.001
S/km. Given a sending end voltage of 220 kV and a sending end current of 100 A.
Calculate the propagation constant, characteristic impedance, ABCD parameters, and
determine the receiving end voltage and current. Implement the solution using MATLAB
and verify the results through hand calculations.
Output:
Receiving End Voltage (Vr): 244497.31 + j70965.00 V
Receiving End Current (Ir): 5832.83 + j5929.65 A
ABCD Parameters:
A = 1.1042 + j0.3177
B = 15.6863 + j10.8032
C = 0.0260 + j0.0268
D = 1.1042 + j0.3177
6. A 150km, 3Φ overhead transmission line has a resistance of 48.7Ω/ph, inductive reactance
of 80.2Ω/ph and capacitance 8.42nF/km. It supplies a load of 13.5MW at a voltage of
88kV and 0.9 pf lagging. Using the nominal T-Method, find regulation and efficiency.
Write a MATLAB code to calculate the parameters.
Output:
Product of AD-BC=1
Is = 87.5759 -21.1964i
vsl = 9.9881e+004 +9.5311e+003i
eff = 91.2127
reg = 15.8545
7. A 150km, 3Φ overhead transmission line has a resistance of 48.7Ω/ph, inductive reactance
of 80.2Ω/ph and capacitance 8.42nF/km. It supplies a load of 13.5MW at a voltage of
88kV and 0.9 pf lagging. Using the nominal π-Method, find regulation and efficiency.
Write a MATLAB code to calculate the parameters
Output:
Is = 87.4784 -21.3568i
vsl = 1.0003e+005 +9.5354e+003i
eff = 91.1949
reg = 16.0260
8. Write a MATLAB program to determine sequence components for unbalanced three phase
voltage Va= 200∠0° , Vb= 200∠245° , Vc= 200∠105° .
Output:
Zero-sequence voltage (Va0): Magnitude = 21.61 V, Angle = 10.60°
Positive-sequence voltage (Va1): Magnitude = 197.81 V, Angle = -3.32°
Negative-sequence voltage (Va2): Magnitude = 20.15 V, Angle = 158.24°
9. Write a MATLAB program to determine sequence components for unbalanced three phase
three- wire system with current Ia= 0∠0° , Ib= 33.33∠0° , Ic= -33.33∠0° .
Output:
Zero-sequence current (Ia0): Magnitude = 0.00 A, Angle = 0.00°
Positive-sequence current (Ia1): Magnitude = 19.24 A, Angle = 90.00°
Negative-sequence current (Ia2): Magnitude = 19.24 A, Angle = -90.00°
10. Write a MATLAB program to determine sequence components for unbalanced three phase
four- wire system with current Ia= 30∠0° , Ib= 30∠240° , Ic= 30∠120° .
Output:
Zero-sequence current (I0): Magnitude = 0.00 A, Angle = 135.00°
Positive-sequence current (I1): Magnitude = 30.00 A, Angle = -0.00°
Negative-sequence current (I2): Magnitude = 0.00 A, Angle = 56.31°
11.
Write a MATLAB program to determine sequence components for unbalanced three phase
voltage Va= 120∠0° , Vb= 130∠225° , Vc= 240∠115° .
Zero-sequence voltage (Va0): Magnitude = 48.48 V, Angle = 120.29°
Positive-sequence voltage (Va1): Magnitude = 162.57 V, Angle = -6.42°
Negative-sequence voltage (Va2): Magnitude = 29.21 V, Angle = -125.84°
12. SLG FAULT ON BUS.5 : NAME Bus5
--------- -------- --------- -------- ---------------- ------------- --------- --------- --------- --------
CURRENT (AMP/DEGREE) MVA
SEQUENCE (1,2,0) PHASE (A,B,C) SEQUENCE (1,2,0) PHASE (A,B,C)
A deg A deg MVA MVA
--------- -------- --------- -------- ---------------- -------------
1294.330 -89.999 3882.989 -89.999 246.603 739.809
1294.330 -89.999 0.000 0.000 246.603 0.000
1294.330 -89.999 0.000 0.000 246.603 0.000
Ia0 = 1294.330∠-89.99 A , Ia1=1294.330∠-89.99 A , Ia2 = 1294.330∠-89.99 A
Fault current (If) = 3*|Ia0| = 3882.99 A
IA = Ia0+Ia1+Ia2 = 3882.9∠-89.99 A
IB =Ia0+a^2*Ia1+a*Ia2 = 0 A
IC =Ia0+a*Ia1+a^2*Ia2 = 0 A
Result :- Fault current is obtained at BUS-5 for SLG fault = 3882.99 A
%--------------------------------------------------------------------------------------------------------------------------------------%
13. LL FAULT ON BUS.5 : NAME Bus5
--------- -------- --------- -------- ---------------- ------------- --------- --------- --------- --------
CURRENT (AMP/DEGREE) MVA
SEQUENCE (1,2,0) PHASE (A,B,C) SEQUENCE (1,2,0) PHASE (A,B,C)
A deg A deg MVA MVA
--------- -------- --------- -------- ---------------- -------------
2283.484 -89.999 0.000 0.000 435.062 0.000
2283.484 90.001 3955.110 -179.999 435.062 753.550
0.000 0.000 3955.110 0.001 0.000 753.550
Ia0 = 0 ∠0 A , Ia1 = 2283.484 ∠-89.999 A , Ia2 = 2283.484 ∠90.001 A
Fault current (If) =√3*|Ia1| = 3955.1103 A
IA = Ia0+Ia1+Ia2 = 0 A
IB =Ia0+a^2*Ia1+a*Ia2 = 3955.11∠-179.99 A
IC =Ia0+a*Ia1+a^2*Ia2 = 3955.11 ∠0.00 A
Result :- Fault current is obtained at BUS-5 for LL fault = 3955.1103
14. LLG FAULT ON BUS.5 : NAME Bus5
--------- -------- --------- -------- ---------------- ------------- --------- --------- --------- --------
CURRENT (AMP/DEGREE) MVA
SEQUENCE (1,2,0) PHASE (A,B,C) SEQUENCE (1,2,0) PHASE (A,B,C)
A deg A deg MVA MVA
--------- -------- --------- -------- ---------------- -------------
2665.007 -89.999 0.000 -89.998 507.752 0.000
1734.469 90.001 4057.673 159.881 330.461 773.091
930.538 90.001 4057.698 20.121 177.291 773.095
Ia0 = 930.538 ∠90.001 A , Ia1 = 2665.007 ∠-89.999 A , Ia2 = 1734.469 ∠90.001 A
Fault current (If) =3*|Ia0| = 2791.614 A
IA = Ia0+Ia1+Ia2 = 0.07 ∠-90.00 A
IB =Ia0+a^2*Ia1+a*Ia2 = 4057.68 ∠159.88 A
IC =Ia0+a*Ia1+a^2*Ia2 = 4057.72∠20.120 A
Result :- Fault current is obtained at BUS-5 for LLG fault = 2791.614 A
%----------------------------------------------------------------------------------------------------------------------------------%
15. LLLG FAULT ON BUS.5 : NAME Bus5
--------- -------- --------- -------- ---------------- ------------- --------- --------- --------- --------
CURRENT (AMP/DEGREE) MVA
SEQUENCE (1,2,0) PHASE (A,B,C) SEQUENCE (1,2,0) PHASE (A,B,C)
A deg A deg MVA MVA
--------- -------- --------- -------- ---------------- -------------
3870.328 -89.999 3870.328 -89.999 737.397 737.397
0.000 0.000 3870.328 150.001 0.000 737.397
0.000 0.000 3870.328 30.001 0.000 737.397
Ia0 = 0 ∠0 A , Ia1 = 3870.328 ∠-89.999 A , Ia2 = 0 ∠0 A
Fault current (If) =Ia1 = 3870.32 ∠-89.999 A
IA = Ia0+Ia1+Ia2 = 3870.32 ∠-89.999 A
IB =Ia0+a^2*Ia1+a*Ia2 = 3870.31 ∠150.001A
IC =Ia0+a*Ia1+a^2*Ia2 = 3870.31 ∠30.00 A
Result :- Fault current is obtained at BUS-5 for LLLG fault = 3870.32 ∠-89.999 A
%--------------------------------------------------------------------------------------------------------------------------------------%
16. SLG FAULT ON BUS.1 : NAME Bus1
--------- -------- --------- -------- ---------------- ------------- --------- --------- --------- --------
CURRENT (AMP/DEGREE) MVA
SEQUENCE (1,2,0) PHASE (A,B,C) SEQUENCE (1,2,0) PHASE (A,B,C)
A deg A deg MVA MVA
--------- -------- --------- -------- ---------------- -------------
56271.015 -90.000 168813.044 -90.000 1072.107 3216.320
56271.015 -90.000 0.000 0.000 1072.107 0.000
56271.015 -90.000 0.000 0.000 1072.107 0.000
17. LL FAULT ON BUS.2 : NAME Bus2
--------- -------- --------- -------- ---------------- ------------- --------- --------- --------- --------
CURRENT (AMP/DEGREE) MVA
SEQUENCE (1,2,0) PHASE (A,B,C) SEQUENCE (1,2,0) PHASE (A,B,C)
A deg A deg MVA MVA
--------- -------- --------- -------- ---------------- -------------
58628.099 -90.000 0.000 0.000 1117.015 0.000
58628.099 90.000 101546.846 -180.000 1117.015 1934.727
0.000 0.000 101546.846 0.000 0.000 1934.727
18. LLG FAULT ON BUS.3 : NAME Bus3
--------- -------- --------- -------- ---------------- ------------- --------- --------- --------- --------
CURRENT (AMP/DEGREE) MVA
SEQUENCE (1,2,0) PHASE (A,B,C) SEQUENCE (1,2,0) PHASE (A,B,C)
A deg A deg MVA MVA
--------- -------- --------- -------- ---------------- -------------
4681.736 -89.998 0.000 -90.007 891.991 0.000
2218.988 90.001 7025.827 148.280 422.774 1338.600
2462.748 90.003 7025.726 31.724 469.217 1338.581
19. LLLG FAULT ON BUS.4 : NAME Bus4
--------- -------- --------- -------- ---------------- ------------- --------- --------- --------- --------
CURRENT (AMP/DEGREE) MVA
SEQUENCE (1,2,0) PHASE (A,B,C) SEQUENCE (1,2,0) PHASE (A,B,C)
A deg A deg MVA MVA
--------- -------- --------- -------- ---------------- -------------
3870.328 -89.999 3870.328 -89.999 737.397 737.397
0.000 0.000 3870.328 150.001 0.000 737.397
0.000 0.000 3870.328 30.001 0.000 737.397
20. SLG FAULT ON BUS.2 : NAME Bus2
--------- -------- --------- -------- ---------------- ------------- --------- --------- --------- --------
CURRENT (AMP/DEGREE) MVA
SEQUENCE (1,2,0) PHASE (A,B,C) SEQUENCE (1,2,0) PHASE (A,B,C)
A deg A deg MVA MVA
--------- -------- --------- -------- ---------------- -------------
56271.015 -90.000 168813.044 -90.000 1072.107 3216.320
56271.015 -90.000 0.000 0.000 1072.107 0.000
56271.015 -90.000 0.000 0.000 1072.107 0.000
%-------------------------------------------------------------------------------------------------------------------------------------%
