Follow Our FB Page << CircleMedia.in >> for Daily Laughter. We Post Funny, Viral, Comedy Videos, Memes, Vines...


An 11kv system consisting of an underground cable to a sub
station about 300 meters away was shut down for about 10
hrs. On energising, it tripped off on earth fault about
10---20 mins later 6 times but since than it is not
tripping.its already 3 weeks now. The SPAJ was found to be
fine. what could be the cause.No test had been done to
determine the cause of the trippings till now because of
demand.

Answers were Sorted based on User's Feedback



An 11kv system consisting of an underground cable to a sub station about 300 meters away was shut d..

Answer / k.prakashchandra

If only you had replaced the breaker cubicle and test
charged you would have come to conclusion.If the all 3 poles
do not close almost at the same time and there is a time
gap, the breaker is likely to trip on EFR due to the
unbalanced current in case of 2 OCR + 1 EFR protection
scheme.In such cases it is advisable to test charge on no
load during the second time and confirm the mechanical fault
which is not consistent & does not occur always.

Is This Answer Correct ?    1 Yes 0 No

An 11kv system consisting of an underground cable to a sub station about 300 meters away was shut d..

Answer / pillay

thanks but I had managed to ON the system and remained
energized with some load for a few minutes (10 -20 mins)
before it tripped again on earth fault , it happened 6 times
on (4/6/2011) and till today (13/07/2011) no problem. we
are using ABB spaj oc/ef relay.

Is This Answer Correct ?    0 Yes 0 No

Post New Answer

More Electrical Engineering Interview Questions

A logic circuit that provides a HIGH output if one input or the other input, but not both, is HIGH, is a(n)?

0 Answers   Ittiam Systems,


which gas is filled in CFL

7 Answers   Lumax,


Why earthing is required, and what effect in earthing result is more than 5 ohm and less than 5 or equal to 0 ohm

2 Answers  


WHY THE SYNCHRORONOUS MOTOR IS NOT SELF STARTING, AND WHY THE STATOR AND ROTOR IS COUPLED?

3 Answers   Essar, GCUF,


why we are called the 4-20ma transducer,not 0-20 ma transducer??

3 Answers  






what about GD square and its important for motor design?

0 Answers   Innovis, MNC,


what is the use of surge suppresser in 33 KV incoming panel. where it must be installed,inseries with incoming cable surge suppresser must be at incoming of the breaker are outgoing of the breaker

1 Answers   Siemens,


What is SF6 Circuit Breaker?

10 Answers   Sodexo,


what is the magnitude of earthing and neutral voltage

2 Answers  


Why Trasformers rated in KVA

13 Answers   College School Exams Tests, HAL, Oil and Gas Jobs,


what is real and reactive power?

2 Answers  


What do you mean by phasors?

0 Answers  






Categories
  • Civil Engineering Interview Questions Civil Engineering (5075)
  • Mechanical Engineering Interview Questions Mechanical Engineering (4444)
  • Electrical Engineering Interview Questions Electrical Engineering (16597)
  • Electronics Communications Interview Questions Electronics Communications (3915)
  • Chemical Engineering Interview Questions Chemical Engineering (1092)
  • Aeronautical Engineering Interview Questions Aeronautical Engineering (214)
  • Bio Engineering Interview Questions Bio Engineering (96)
  • Metallurgy Interview Questions Metallurgy (361)
  • Industrial Engineering Interview Questions Industrial Engineering (258)
  • Instrumentation Interview Questions Instrumentation (2987)
  • Automobile Engineering Interview Questions Automobile Engineering (332)
  • Mechatronics Engineering Interview Questions Mechatronics Engineering (97)
  • Marine Engineering Interview Questions Marine Engineering (123)
  • Power Plant Engineering Interview Questions Power Plant Engineering (170)
  • Textile Engineering Interview Questions Textile Engineering (575)
  • Production Engineering Interview Questions Production Engineering (0)
  • Satellite Systems Engineering Interview Questions Satellite Systems Engineering (106)
  • Engineering AllOther Interview Questions Engineering AllOther (1377)