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.

Two CTs 1600/1 and 35/1 are in series. while checking the ratio test of a CT(1600/1),same 1600A will also pass through the CT having ratio 35/1. Will it be harmfull to the ct(35/1),if yes , what will happen.CT secondary is shorted

3 Answers  

---

whytransformers rating in KVA?

3 Answers   Chettinad,

---

what are the reasons of low voltage during start the DG?

1 Answers   Godrej, Tata Power,

---

WHAT IS THE USE OF PIG TAIL IN WINDOW CT ?

0 Answers  

---

What is mean by sinewave.

0 Answers  

---

solar energy light efficiency & disadvantages?

0 Answers  

---

Iam deepthi.i completed my b.tech from electrical engineering.i want to prepare for civil services.i dont have much knowledge about these exams,but i have great zeal of cracking exams.plz provide me suggestions to which options i can select for optionals

7 Answers  

---

what is meant by brushed alternator & its working principle ?

0 Answers  

---

What will be in Mahagenco Trade Test Exam? I want to know the same.

0 Answers   MahaGenco,

---

why we somewhere use ryb phase sequance, somewhere use uvw, and somewhere abc??

4 Answers  

---

What is primary and backup protection?

0 Answers  

---

Can we use both Electrical & mechanical interlock between tow breakers? if yes how, please explain

0 Answers  

---