Answer / manisand1

CT resistance = 1.8ohm,
Lead resistance = 4.0 ohm,
Starting current = 195*5/200 = 4.875 Amp
Starting voltage = 4.87(1.8+4)= 28.275 = 28.3 volts
This is to be set to 30Volt,

But please remember that knee voltage should be 60 volt
minimum.

For anymore clarification you can mail me to :-
manisand1@hotmail.com

Answer / puneet prashar

Knee Voltage=2X Earth Fault current(RCT + RW)/CT
Trasformation ratio

Where
RCT= CT impedeance as per manufacture1.02
RW = Wire resistance as per manufactre
say.oo32/metre then RW= 2X 200mtr X .0032

CT transformation ratio= 4000/1=4000
4000/5=800

VKnee= 2X58000(1.02+1.28)/4000 or 800 depending upon ct used

Vknee= 66.7v

Vknee> relay stability Voltage

Relay stability voltage formula will be given by relay
manufacturer as every relar manufacturer has their own formulas

working of diesel generator ?

0 Answers  

---

how to write program by ladder logic in case of PLC operation

3 Answers   Gridco, Sofcon,

---

galloping in transmission line is due to

2 Answers   DVC,

---

tell how current tranfomer works

2 Answers  

---

What is EPBX????

3 Answers   Emerson,

---

Is it necessary to place tap changer in secondary winding or we can use on both sides?

3 Answers  

---

Rotor resistance starter is used to obtain= A increased starting torque B decrease starting current C decrease starting loss D increase efficiency

1 Answers  

---

why we use isolation transformer?

2 Answers   Godrej,

---

What is the latest generation of circuit breakers called?

3 Answers   Epitome, Focus Energy, Jakson, KDC, L&T,

---

why are the a.c.series motors preferred for electric traction

4 Answers  

---

why always electric field is linked with magnetic field???

2 Answers   Bhushan Power Steel, NTPC, Tata Steel Limited,

---

Why generally the Rating of Transformers are in additions of 11 i.e. 11 kVA, 22 kVa, 33 kVA, etc........

8 Answers  

---