Tutorial 8: Sequence Components and Sequence Networks
8.1 The phase voltages at a bus of an unbalanced power system are
Va 100 , Vb 1 900 , Vc 21350 , find the sequence voltages of
three unbalanced voltages and Prove that:
0
1
2
Va Va Va Va .
Solution:
Va
1
Tutorial 3: Synchronous Generators 1
Equivalent circuit and basic concepts:
IIa
The magnitude of
jX s
generated voltage (or emf)
V
E
E is produced by the field
or excitation current If .
Real power output P is
E=V+IjXs E
converted from mechanical
V: th
TUTORIAL 7: THREE-PHASE POWER SYSTEMS
7.1: Three (30 + j30) identical impedances are connected in Delta and supplied by a
173V 3-phase system through three lines each having impedance of (0.8 + j0.6) . Find:
1) the current magnitude in each of the delta-c
1
Tutorial 4: Synchronous Generators II
1. Relationship among f, n, and p: f
np
120
fnl
f
ffl
2. For a single machine:
Pfl
fnl ffl
P-f or droop curve: P S p (fnl f )
Slope of droop: S P
Pfl
P
3. Real power sharing for parallel machines:
All machines mus
1
Tutorial 6: Symmetrical Faults
1. Thevenin Equivalent of a power system
f
seen from bus f:
Power
Pre-fault voltage at bus f : Vf =Vth
system
Thevenin impedance at bus f: Zff= Zth
Fault current from bus f to ground: If=Vf/Zff
Fault Level or Short cir
Tutorial 9: Fault Analysis
9.1 The one-line diagram for a power system is given in the following figure. The
parameters of the generators and transformers are given as:
G1 and G2: 100MVA, 20kV, X 1 X 2 20%, X 0 6% and X N =5%.
Transformers T1 and T2: 100M