WorksheetsT & C of UPD Project
Total questions: 15
Worksheet time: 13mins
What should be the minimum IR value of HT & LT winding for Distribution substation :
The thumb rule is 10 Mega ohm/kV
The thumb rule is 5 Mega ohm/kV
The thumb rule is 1 Mega ohm/kV
None
Which type of precaution not required during testing?
Equipments body to be earthed properly
Testing area should not be barricaded
Proper skilled person only allowed for testing
Power supply used for testing should be proper and its better to avoid DG supply for testing
What is DCRM test in Circuit Breaker ?
Dynamic capacitance & resistance measurement
Dynamic contact resistance measurement
Different circuit resistance measurement
None
What is the relevant IEC to perform sheath test after cabling laying
IEC 60229
IEC 60220
IEC 60210
None
In the earth pits the layer of charcoal and salt helps to maintain low resistance for earth fault currents. if climate is too dry then :-
we have to pour the water atleast three month once
we have to pour the water atleast one year once
we have to pour the water atleast six month once
None
Transformer Dyn11 vector connection means :
primary is delta & secondary is star
primary is star & secondary is delta
It does not furnish complete information to predict anything
None
Toroidal type CT
Have primary & secondary on same core
do not contain a primary winding
do not contain a secondary winding
None
what should be the minimum earth resistance to be maintained in Distribution substation.
for grid it should be less than 5 ohm
for grid it should be less than 10 ohm & greater than 5 ohm
for grid it should be less than 15 ohm & greater than 5 ohm
None
What is CBCT?
Core Below Current Transformer
Core Balance Current Transformer
Core Between Current Transformer
None
CBCT is used for earth fault protection for :
Extra High Voltage system
High Voltage system
low and medium voltage system
None
Normal earth fault protection
operate very fast
operate late
Not operate independently
None
REF protection is restricted earth fault protection where the transformer having
star winding without neutral
star winding with neutral
delta winding with neutral
None
what should be the value of neutral earthing of 10 mva power transformer?
neutral earthing should be less than 15 Ohm
neutral earthing should be less than 10 Ohm
neutral earthing should be less than 5 Ohm
None
why specifically SF6 gas is used in CB?
Sulphur hexa flouride gas has good insulation property and arc quenching media
SF6 Gas have no environmental effect
SF6 Gas have no effect on Human Being
what is the highest voltage rating of auto reclosure and sectionalizer in over head line ?
11 KV
24 KV
33 KV
36 KV
