Answer / siva

The restriction of current flow from the Earth Faults which
are Caused outside the Circuit of the Protected Equipment is
called Restricted Earth fault relay.

It is act as defense from nuisance!

Answer / jrk

EARTH FAULT CAUSED WITH IN ZONE IS CALLED RESTRICTED EARTH
FAULT.

Answer / sumit

REFP is mainly used for high speed tripping on star connected earthed secondary winding of power transformer

The relay does not operate for fault beyond the protected zone i.e neutral of the transformer.

Fault occurring near neutral is having small current becoz of small voltage which results in low fault current. To attend this fault the relay must be too sensitive to operate .To operate, the relay is set for the earth fault current of the order 15%of the rated winding current which protects restricted portion of the winding.

without any theoretical calculations, can u approximately tell the current rating of a motor(above 30hp)working at 415VAC.

7 Answers  

---

What is the impedence of Transformer?

2 Answers  

---

what is the difference between switchgear and circuit breakers and is there any difference between outdoor and indoor switchgear and circuit breakers , and how would you differentiate between switch yard and substation and grid station . thanks

0 Answers   ABC,

---

How to test and satisfy the conditions of the vector group YNd1 for power transformer?

1 Answers   Areva,

---

what is insulation percentage of motor 3 phase and singlephase

1 Answers   Infotech,

---

What is mean by Power factor

5 Answers   Fenner,

---

why do transformer humm ??????????

2 Answers  

---

mccb service sittings be done?

0 Answers  

---

why 3 phase motors are preferable over single phase motors ?

4 Answers  

---

Latching current is slightly less than ?

2 Answers  

---

What is AVR in Generators and How is it working.

4 Answers  

---

Define peak overshoot.

0 Answers  

---