ALLInterview.com :: Home Page            
 Advertise your Business Here     
Browse  |   Placement Papers  |   Company  |   Code Snippets  |   Certifications  |   Visa Questions
Post Question  |   Post Answer  |   My Panel  |   Search  |   Articles  |   Topics  |   ERRORS new
   Refer this Site  Refer This Site to Your Friends  Site Map  Bookmark this Site  Set it as your HomePage  Contact Us     Login  |  Sign Up                      
Google
   
 
Categories >> Engineering >> Electrical Engineering
 
 


 

 
 Civil Engineering interview questions  Civil Engineering Interview Questions (3111)
 Mechanical Engineering interview questions  Mechanical Engineering Interview Questions (3298)
 Electrical Engineering interview questions  Electrical Engineering Interview Questions (13408)
 Electronics Communications interview questions  Electronics Communications Interview Questions (2381)
 Chemical Engineering interview questions  Chemical Engineering Interview Questions (421)
 Aeronautical Engineering interview questions  Aeronautical Engineering Interview Questions (77)
 Bio Engineering interview questions  Bio Engineering Interview Questions (17)
 Metallurgy interview questions  Metallurgy Interview Questions (80)
 Industrial Engineering interview questions  Industrial Engineering Interview Questions (165)
 Instrumentation interview questions  Instrumentation Interview Questions (2389)
 Automobile Engineering interview questions  Automobile Engineering Interview Questions (106)
 Mechatronics Engineering interview questions  Mechatronics Engineering Interview Questions (38)
 Marine Engineering interview questions  Marine Engineering Interview Questions (45)
 Power Plant Engineering interview questions  Power Plant Engineering Interview Questions (78)
 Engineering AllOther interview questions  Engineering AllOther Interview Questions (1201)
Question
what is the significance of tan delta testing?explain the 
theory?
 Question Submitted By :: Electrical-Engineering
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
Tan Delta is an effective tool in determining the
insulation condition of power cables using a VLF-TD System
Tan Delta measures the resistive component of a cable
system; a perfect cable is all capacitance and has no
resistance. The resistive component is caused by voids in
the insulation, electrical trees, water trees etc. The
resistive element causes the current not to lead the
voltage by 90 (something less) This is difference in angle
(less than 1 ) is the loss angle. The tangent of this loss
angle is the Tan Delta / or the tangent of the loss angle.


Thanks for Marking this Answer
 
Is This Answer Correct ?    21 Yes 3 No
A.r.shah
 
Answer
# 2
Tan Delta is an effective tool in determining the
insulation condition of power cables using a VLF-TD System
Tan Delta measures the resistive component of a cable
system; a perfect cable is all capacitance and has no
resistance. The resistive component is caused by voids in
the insulation, electrical trees, water trees etc. The
resistive element causes the voltage not to lead the
current by 90 (something less) This is difference in angle
(less than 1 ) is the loss angle. The tangent of this loss
angle is the Tan Delta / or the tangent of the loss angle.
 
Is This Answer Correct ?    27 Yes 10 No
Er. Ankush Miglani 9718151073
 
 
 
Answer
# 3
Ideally an insulation (be it across a cable or a electrical
switch gear) should be of infinite resistance. That is
ideally if voltage is applied across insulation no current
should pass through (considering resistive current only).
Now there is another aspect of an insulation. An insulation
is also a capacitor (two plates seperated by dielectric)
and hence there must be some current (opf course ac
current) that will flow if voltage is applied acroos
insulation (this is capacitive current). Now the ration of
the resistive current (which shoud ideally be zero) and the
capacitive current is called loss tangent or tan delta and
is measurable. So if tan delta is measured we are actually
get an idea of the resistive current through the
insulation. A high tan delta indicates high resistive
current and that means insulation is detoriating.
 
Is This Answer Correct ?    17 Yes 2 No
Koushik Goswami
 
Answer
# 4
tan delta testing is usally carried out to check the
healthiness of insulation.so this testing is usally carried
out in cb ,ct, bushings etc ,for all these equipements one
standard value will be there,for breakers this value will
be 0.00073, if any devation in this value we have to
suspect about it insulation healthyness.
 
Is This Answer Correct ?    19 Yes 7 No
Veena Nair
 
Answer
# 5
Ideally an insulation (be it across a cable or a electrical
switch gear) should be of infinite resistance. That is
ideally if voltage is applied across insulation no current
should pass through (considering resistive current only).
Now there is another aspect of an insulation. An insulation
is also a capacitor (two plates seperated by dielectric)
and hence there must be some current (opf course ac
current) that will flow if voltage is applied acroos
insulation (this is capacitive current).& IDEAL CAPACITIVE
CURRENT IS ALWAYS 90 DEG AHEAD THAN VOLTAGE AS PER R-C
CIRCUIT VECTOR DIAGRAM.BUT DUE TO AGING EFFECT &
DETORIATION OF INSULATION , CAPACITIVE CURRENT IS SLIGHTLY
LESS THAT 90 DEG & ONE ANGLE CREATED BET IDEAL CAPA.
CURRENT & ABOVE SAID CURRENT IS CALLED TAN DELTA ANGLE.
HENCE WE CLEARLY SAY THAT TAN DELTA IS the ration of
the resistive current (which shoud ideally be zero) and the
capacitive current is called loss tangent or tan delta and
is measurable. So if tan delta is measured we are actually
get an idea of the resistive current through the
insulation. A high tan delta indicates high resistive
current and that means insulation is detoriating.
 
Is This Answer Correct ?    9 Yes 0 No
M R Bhanderi
 
Answer
# 6
tan angle is the ratio of resistance current and
capacitive current ..it is used to estimate the life of
insulation by comparing periodical tandelta value of the
same insulation..pure insulation has only capacitive
current but with the insulation deteriorationor cavity
formation(may occur due ambient condition temp or cont.
over current flow) resistance is added hence resistive
current increase wich leads to increase in tandelta value..
 
Is This Answer Correct ?    4 Yes 1 No
Manish Yadav
 
Answer
# 7
In general for electrical component, Ten delta means that the tangent value of insulating material. what is tangent value of IM? it is nothing but the dissipation factor. what is dissipation factor? The ratio of Power/ Voltage-Ampear (W/VA). so finally in simple words Tan delta testing is nothing but to find out the health of insulation OR insulating material.The test can be performed on Cables, power TR's or any electrical component.

hope i am able to answer
 
Is This Answer Correct ?    2 Yes 1 No
Mirza Faiz Baig
 

 
 
 
Other Electrical Engineering Interview Questions
 
  Question Asked @ Answers
 
what are the different types and applications of compressors?   1
Technical specification of a wind farm   1
can any one help me? 1.what is corona extinction voltage&corona inception volatage 2.what is mean by CFVV? Kseb 1
how LT meggar works Essar 1
I did oil BDV test of 1600 KVA trafo 20KV/400V as per IEC 156. Result is 1) 58 KV 2) 58 KV 3)40 KV 4) 50 KV 5) 58 KV 6) 18 KV. Avr is 47 KV. Can we say oil is still ok even in the 6th test BDV is 18 KV ?   1
when any relay trips in any ckt then what type of setting is there in motor?what is function of relay in that ckt? Finolex 3
What is the permissible value of earth resistance and as per which standard / act / rule ? HBL-Power-Systems 3
what is meant by armature reaction & where its happen ?   3
can u tell the difference between star-star transformer and delta to delta transformer. Videocon 3
Is corona effect occurs in Induction motor. pl. justify the answer.   4
what is power ratio between star & delta connection of 3 phase induction motor   1
what is wave trap? please explain the working and principle   4
 
For more Electrical Engineering Interview Questions Click Here 
 
 
 
 
 


   
Copyright Policy  |  Terms of Service  |  Articles  |  Site Map  |  RSS Site Map  |  Contact Us
   
Copyright 2013  ALLInterview.com.  All Rights Reserved.

ALLInterview.com   ::  KalAajKal.com