Question

A 125 MVA 11 kV three phase 50 Hz synchronous generator has a synchronous reactance of 1.33 p.u. The generator achieves rated open circuit voltage at a field current of 325 A. The generator is connected to a network with an equivalent line-line voltage of 11 kV and an equivalent impedance of 0.17 pu on the generator base. The generator is loaded to a real power of 110 MW.

a- Find the generated voltage Eaf in p.u. such that the network is operating at unity power factor at the external network equivalent voltage. Find the corresponding field current, the generator terminal voltage and power factor.

b- Assume that the generator is operating at its rated terminal voltage. Find the generated voltage Eaf in p.u., the corresponding field current, the generator terminal current and power factor.

Answer #1

a) A three phase transformer rated at 30 MVA 10 kV(Δ)/1 kV(Y) is
supplying a load at the low voltage side. The load absorbs 5 MVA,
0.7 power factor lagging at line to line voltage 0.9 kV. The
transformer has an equivalent reactance 0.05 Ω/phase. Assuming 10
MVA and 1 kV as base value, draw the per unit diagram for the
system. Find the Line to Line voltage at the primary side of the
transformer.
b) A three-phase synchronous generator...

A 3-phase, 1.2 MVA, Y-connected, 6.6 KV, 6-poles, 60 HZ,
synchronous generator has a synchronous reactance of 30W and
negligible resistance. The generator is connected to an infinite
bus at 6.6 KV and 60 Hz.
a)Determine the excitation voltage (Ea) when the machine is
delivering rated power at o.8 PF lagging.
b)The field excitation current is increased by 10% without
changing the power input from the prime mover. Find the stator
current (Ia), the power factor and the reactive power...

A 3-phase, 5 MVA, kV, 60 Hz synchronous machine has a
synchronous reactance of 10 ohms per phase. The machine is
connected to kV, 60 Hz bus and is operated as synchronous condenser
(synchronous motor at no-load condition)
a. For normal excitation (excitation voltage terminal voltage),
find the line current. Draw the phasor diagram
b. If the excitation is increased to 150% of the normal excitation,
find the line current and reactive power delivered or absorbed by
the bus. Draw...

A 100 MVA, 13.2 kV three phase generator (G) having a
synchronous reactance of 10% is connected to a three phase Y-Y
transformer T1 which feeds a 132 kV 10 miles transmission line
having an impedance per phase of 2 + j5 ?/mile. At the receiving
end of the transmission line is a Y-Y step down transformer T2.
Three loads are connected to the secondary side of the transformer
T2. Loads are as follows:
Load#1 40 MVA at 0.8 pf...

A 50-Hz, two-pole, 825 kVA, 2300 V, three-phase synchronous
machine has a synchronous reactance of 7.47 and achieves rated
open-circuit terminal voltage at a field current of 147 A.
c. For a constant load power of 700 kW, write a MATLAB script to
plot the terminal current as a function of field current. For your
plot, let the field current vary between a minimum value
corresponding to a machine loading of 825 kVA, leading power
factor, and a maximum value...

Use MATLAB:
A three-phase Y-A transformer is rated 225-kV:24-kV, 400 MVA and
has a series reactance of 6.08 Ohms as referred to its high-voltage
terminals. The transformer is supplying a load of 375 MVA, with
0.89 power factor lagging at a voltage of 24 kV (line-to-line) on
its low-voltage side. It is supplied from a feeder whose impedance
is 0.17 + j 2.2 Ohms connected to its high-voltage terminals. The
total load in the system remains constant at 375 MVA....

A three phases, 6 MVA, 22 kV, 60 Hz synchronous machine has a
synchronous reactance of 10 ohms per phase and has negligible
stator resistance. The machine is connected to the 22 kV, 60 Hz bus
and is operated as a synchronous condenser, Neglect rotational
losses 7
a) For normal excitation, find the stator current. Draw the
phasor diagram.
b) If the excitation is increased to 120 percent of the normal
excitation, find the stator current and power factor, draw...

A 3 phase 11 kv,25 mva, 60 Hz salient pole synchronous motor is
running from a 11 Kv, 60 Hz balanced three phase supply the
meachince reactances are Xd=1.2 pu and Xq=0.6 pu ,neglect the
meachanicalloss and armature copper loss the maximum power input is
obtained with no field excitation determine the power factor of
motor

A three-phase, 9,375 kVA, 13.8 kV, 4-pole, 60 Hz, Y-connected
synchronous generator has a synchronous reactance, Xs = 17.9, and
is connected to an infinite bus at rated voltage. If the rotational
and electrical losses are negligivle, what is Ia, Ef, delta, theta,
Tdrive, Phasor diagram, and power flow diagram (label completely
with numerical values for,
A) the machine as a generator; the prime-throttle is opened and
If is adjusted so that the machine delivers rated kVA, 0.8 pf
lagging,...

The test results of a three-phase synchronous generator with the
rated voltage of 6,600V and the capacity of 50 MVA are as follows.
No-load test result: When the terminal voltage was 6,600V, the
field current was 1280A. Short circuit test result: The field
current required to flow the rated current was 1600A.
Find the rated current of this generator
Find the short-circuit ratio. However, the second decimal shall be
rounded off to obtain the first decimal
Find the synchronous reactance....

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 12 minutes ago

asked 20 minutes ago

asked 29 minutes ago

asked 45 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago