Answer Posted / 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.

Please clarify 1. Icw: rated short circuit working withstand capacity 2. Icu: Rated ultimate breaking capacity 3. Ics: Rated service short circut withstand capacity 4. other specification of ACB

2799

---

What is a signal flow graph?

1131

---

why dimmerstate always connected in star connection? what will happen if it connected in delta?

2113

---

I Need standard operation procedure(SOP)for 500kva Oil type transformer oil filtration & Procedure for IR value checking.

2941

---

1.Can we use 6.6/11KV 300sq mm xlpe 3core cable for LT use (415 Volt). 2. If we use it for LT then what is the current rating

1833

---

What kind of maintenance is conducted for Transformer

2366

---

What does bode plots shows?

1226

---

why we use condenser in the thermal power plant, althrough the same vapour will be again heated

4986

---

What are root loci?

1153

---

explain working principle of earth leakage relay

3762

---

How can you calculate the size of the down conductor cable for the lightning protection system. Is 70mm2 cable can replace 95mm 2 bare copper cable when the copper tape size is 25Wx3 thk mm.

5444

---

where lt & ht capacitor used

2279

---

What are approaches to tackle sedimentation problem of reservoir?

1076

---

In the ACB breaker capacity is 2000Amp but this each phase taken 1250 But total beldibg load is 600amp or 700amp watt is the problem

2016

---

Single phase and threephase power calculation

2181

---