The one-line diagram of a three-bus power system is shown in
Figure 4. All impedances are
expressed in per unit on a common MVA base. All resistances and
shunt capacitances are
neglected. Information on each component in this system is given
below:
• Each generator is represented by an emf
behind the sub-transient reactance of j0.045
and their neutrals are connected to the
ground.
• Line 1-2 has reactance of j0.88
• Line 2-3 has reactance of j0.65
• Line 1-3 has reactance of j0.4
• The generators are operating on no load at
their rated voltage (1.02 per unit) with their
emf in phase.
a) Construct the bus impedance matrix by adding one impedance
element at a time and
using the matrix elimination technique, when needed.
b) Consider, a three-phase fault, which occur sequentially at bus
1, 2 and 3 through a fault
impedance of Zf=j0.20 per unit. Find the bus location at which
fault current in per unit is
the most severe.
c) Determine the healthy bus voltages for the fault location at bus
3.
A second line is built between Bus 1 and Bus 2 with an impedance of
j0.88.
d) Repeat Questions (a), (b) and (c) for the new power
systems.
e) Compare the bus matrix in this case with the original bus
matrix. What is the implication
of introducing the second transmission line between bus 1 and bus
2?
Figure 4
The one-line diagram of a three-bus power system is shown in Figure 4. All impedances are...
The one line diagram of a three-phase power system is shown in Fig.8. Impedances are marked in per unit on a 100 MW, 400 kV base. The Load at Bus 2 is S2 = 15.93 MW - j33.4Mvar, and at Bus 3 is S3 = 77 MW + j14 Mvar. It is required to hold the voltage at Bus 3 at 400 kV, Angle 0 degs. Working in per unit, determine the voltages at Buses 2 and 1. Q8: The...
The one-line diagram of a simple power system is shown in Figure 1. The neutral of each generator is grounded through a current-limiting reactor of 0.25/3 per unit on a 100-MVA base. The system data expressed in per unit on a common 100-MVA base is tabulated below. The generators are running on no-load at their rated voltage and rated frequency with their emfs in phase. Determine the fault current for the following faults giving Zo = 0.35, Z = 0.22...
2. A single-line diagram of the power system considered is shown in Figure P2a, where negative- and zero-sequence reactances are also given. The neutrals of the generator and A-Y transformers are solidly grounded. The motor neutral is grounded through a reactance Xn = 0.05 per unit on the motor base. The per-unit zero-, positive and negative-sequence networks on a 100-MVA is shown in Figure P26, 13.8-kV base in the zone of the generator. a. Reduce the sequence networks to their...
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symmetrical three phase fault at bus 4 the fault current the bus voltages all the line currents all find y bus ysy ews in fhe Figune 1,gven the per unit bus impedance matri 20 240 0140 0200 0200 a140 02275 0175 0175 Zp 200 G175 0310 0310 0200 0175 0310 0500 20 050 N2 Condinut the yusmai hee feut sccurs at bus 4 at no lead, find The fault current 2 The bus tages and 3The line carent 1during fault...
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