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Answer #1

Way of transformer neutral earthing are-

1) Solid earthed system - It is used for LV system with low value of fault current.

2) Resistance earthing system- It is used for HV and LV system with high value of fault current. Solid earthing is not used because high value of fault current will cause tripping of all phase and damage to equipment.

3) Resonant earthing system- In this reactor is used between transformer neutral and station earthing. Best example of it is peteson coil.

It is used in power system if capacitive coupling is high that is large amount of cables are used in transformer.

The transformer is protected by a differential relay. The relay
is connected to three phase transformer, 50 MVA, 22 kV/33 kV delta
– star connection. The relay is connected in delta. The current
transformer ratio is 1500/5 Amp at the lower voltage and 1000/5 Amp
at the high voltage. Calculate the primary and secondary current of
the relay and it’s the primary turns. State any assumption.

How does current transformer work? what is its
function?

A Wye-Delta transformer is connected to a 66 kV input
three-phase transmission line. Each transformer is rated at 1000
kVA and has a step-down ratio of 8:1. The bank supplies a balance
load having a power factor of 0.8 lag with a load current of 70 A.
Assume ideal transformer, determine.
The primary line and phase voltages
The secondary line and phase voltages
The secondary line and phase currents
The apparent and active power at the load
Total kVA capacity...

Plate values of a three-phase transformer are given below:
1600 kVA, 15 kV / 0,4 kV, 50 Hz, i0 = 1.2%;
ukN= 6%, idle losses 2450 W, rated power copper losses
14500 W; Dy5 connected..
III) There is 75% load in the power factor with 0.85 inductance
and 0.85 capacity. At what times of the day can capacity loading be
seen? What solution should be applied to prevent voltage
change?
IV) Draw the fastening group. How can this transformer be...

I have a transformer with a maximum capacitance specification
between two discrete windings, how can I design the coil to have
minimum capacitance? What other transformer parameters might this
design requirement effect?

Using a diagram illustrate how a delta/star transformer can be
connected to give standard polarity and standard phase
sequence.

Plate values of a three-phase transformer are given
below:
1600 kVA, 15 kV / 400 V, 50 Hz, io = 1.2%; ukN = 6%, idle losses
2450 W, rated
copper losses of power 14500 W; Dy5.
a) Calculate primary and secondary line and phase currents.
b) Secondary at 75% load in power factor with 0.85 inductance and
0.85 capacity
calculate the voltage separately. Compare and interpret the
results. capacity
at what time of day can the upload be seen? To...

Plate values of a three-phase transformer are given
below:
1600 kVA, 15 kV / 400 V, 50 Hz, io = 1.2%; ukN = 6%, idle losses
2450 W, rated
copper losses of power 14500 W; Dy5.
a) Calculate primary and secondary line and phase currents.
b) Secondary at 75% load in power factor with 0.85 inductance and
0.85 capacity
calculate the voltage separately. Compare and interpret the
results. capacity
at what time of day can the upload be seen? To...

How can graphing methods be used to solve a system of linear
equations, and how can you determine the equations of the two lines
by analyzing the graph?

How can graphing methods be used to solve a system of linear
equations, and how can you determine the equations of the two lines
by analyzing the graph?

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