Answer / k.prakashchandra

Which relay ? SEFR or back -up EFR ? Are the gens connected
to grid ? Whether all the gens trip simultaneously ?
Whenever there is a momentary heavy earth fault in the
outgoing feeder,all the gens trip on back-up EFR with
instantaneous trip indication,though the line does not
trip.So ,it is advised to disable instantaneous fault trip
i.e. high-set of the back-up EFR.

Answer / k.prakashchandra

Another probability. If there is any earth fault before the
GT primary bushings ,the gen may trip on SEFR if voltage
based( open delta) relay is used.Then you have to check
cable,termination glands and the stator winding for earth
fault either by meggering or better by applying rated voltage.

Answer / biplab

check the stator insulation with megger of each gen........

Answer / ronnie

this might be the result accumulation of moisture near the
earthing bit during evening time.which causes the generator
to trip showing earth fault....

A 3-PHASE TRANSFORMER IS USED TO STEP-DOWN THE VOLTAGE OF A 3-PHASE, 11KV FEEDER LINE. PER-PHASE TURNS RATIO IS 12.FOR A PRIMARY LINE CURRENT OF 20A, CALCULATE THE SECOUNDRY LINE VOLTAGE, LINE CURRENT AND OUTPUT KVA FOR FOLLOWING.A)STAR- DELTA.B)DELTA-DELTA.

0 Answers   Ispat, Red Bull,

---

Can Anyone Answer anyone of these ? Q1) why direct SOLUTION of Load Flow Studies in Not Possile ? Q2)Why majority of Buses in power system are load buses Q3)Why one of the buses in Power system is taken as reference bus (slack or swing) Bus ? Q4)Bus Admittance Matrix is a sparce (means it contains some zero elements ) matrix , give reason

0 Answers  

---

What is rotary phase converter?

0 Answers  

---

For these 2 devices what their power ratings are ? 1) single phase : AC 220V & starting amps 3Amps (i.e. starting torque) and the stabilized amps 2A ... For deep freezer 2) single phase : AC 220V & starting amps 2.7Amps (i.e. including the starting torque of a CRT monitor) and the stabilized amps 1 Amps thanks

1 Answers  

---

What is the function of the auto reclosure relay?

1 Answers  

---

---

What is the deffirant between EARTH, GROUND AND NUTRAL

4 Answers  

---

what do you call the last pole on a overhead line near a substation

2 Answers  

---

# 4 hi friends i m from electrical branch and seeking for tech. + apti. both papers of hpcl plz get it available as soon as possible my email id is sumit_lig189@yahoo.co.in

0 Answers   HPCL,

---

what is positive,negative and zero sequence in power system?

4 Answers  

---

What is the diffrence between an ELCB(earth leakage circuit breaker) and RCCB(residual current circuit breaker)?which has higher degree of safety and why?

2 Answers  

---

Classify milling machines.

0 Answers   Ashok Leyland,

---

What is meant by shunt current?

1 Answers   ABC,

---