Answer / ram niveth

REF is a backup protection for transformer incipient
faults.
if differential fails REF comes on line.
if both protections are used , usually REF time setting
will be less than differential setting

Answer / shipra

restricted earth faukt protn is for unprotected zone of
neutral to earth.
Diffetential protn will work only if the falt is with in
zone of CT so that it can get a differential current. If
there is a fault between neutral CT and earth the fault
will be feeded and no diffential current will be there as
it is balaced through primary side, secndary side & nutral.

Answer / erharisheee51

RESTRICTED EARTH FAULT PROTECTION IS GENERALLY PROTECT FROM
THE DEFFERENTIAL CURRENT WITH IN THE GENERATOR CORE , WHERE
AS DIFFERENTIAL PROTECTION IS USED FOR OVERALL DIFFERENTIAL

Answer / pradeep

mainly there is some drawbacks in differential protection.
the protection is mostly surrounding at the certain region.
for example, if the transmission line length is 10km
means,we locate differential protection in between the
transmission line we can't able to protect the outerside of
the transmission line. so that we go for earth fault
protection. earth consist the infinite resistance.

how much distance is required for earth pit to earth pit in substation???

3 Answers   Divis Laboratories,

---

What is NGR . What is the purpose of 10 sec ,60 sec rating of NGR.

0 Answers   KOTC,

---

Load break swicth maintenance procedure.

0 Answers   KSEB, L&T, Siemens,

---

what is the meaning of bus bar, in electrical panels.

13 Answers   HLG Habtoor Leighton Group,

---

sir i want previous entrance exam papers for written test

0 Answers   Vizag Steel,

---

---

what voltage to be select in megger for insulation resistance testing to L.V , H.T cables,motors and transfomer?and ohms valve should be giga ohms only or what?

1 Answers   Deevya Shakti Paper Mills,

---

How to desaturate a saturated CT of PS Class?

4 Answers   Electrical,

---

Why transformer use to generator neutral earthing purpose ?

1 Answers  

---

Distinguish between neutral earthing and equipment earthing?

7 Answers  

---

What is the diff. between single compression and double compression gland

0 Answers   ASL,

---

what is the difference between synchronous generator & asynchronous generator

4 Answers   Reliance,

---

i have to use generator in my project,which gen. i can use?

1 Answers  

---