Previous in Forum: Regenerative Braking   Next in Forum: Voltage Drop & Cable Sizing
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
15 comments
Rate this Comments: Nested
garuda777
Active Contributor

Join Date: May 2011
Posts: 18

Leakage Current of Hi-Pot Test

03/29/2014 4:33 AM

Dear all,

In my project we had some MV cables and the design voltage of that cables are 6.6 KV.

During the hipot test time we applied 11 KV to that cables and we got the leakage current is zero value.

anybody can explain that why the leakage current was zero and that test was valid or not?
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
JohnDG
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 9684
Good Answers: 468
#1

Re: Leakage current of hi-pot test

03/29/2014 8:15 AM

Provided that the test equipment was working correctly and being used correctly, the test was valid.

A reading of zero means that the leakage current was below the measuring range of the meter - and therefore obviously below the maximum permissible leakage.

On the test record sheet, if there is a space to record the leakage current, write "<x", where x represents the smallest unit displayed by the instrument.

__________________
 "Love justice, you who rule the world" - Dante Alighieri
Register to Reply Score 1 for Good Answer
No more "Almost" Good Answers.
lyn
Guru

Join Date: Oct 2008
Posts: 42376
Good Answers: 1692
#2

Re: Leakage Current of Hi-Pot Test

03/29/2014 11:40 AM

Perhaps, if you knew what the test was and why it is performed you wouldn't have to ask. It is unclear to me why one would perform a test when they don't know what the test is for.

What is HIPOT Testing (Dielectric Strength Test)? | EEP
Register to Reply Off Topic (Score 4)
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32119
Good Answers: 838
#15
In reply to #2

Re: Leakage Current of Hi-Pot Test

11/27/2023 8:47 AM

Quite.

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply Off Topic (Score 5)
SimpleMind
Guru

Join Date: Sep 2009
Posts: 1055
Good Answers: 88
#3

Re: Leakage Current of Hi-Pot Test

03/29/2014 2:51 PM

If you came up with an insulator of ZERO leakage current, you're on your way to a Nobel prize. It's all about measurement resolution and accuracy. S.M.

__________________
 Life is complex. It has a real part and an imaginary part.
Register to Reply
lyn
Guru

Join Date: Oct 2008
Posts: 42376
Good Answers: 1692
#4

Re: Leakage Current of Hi-Pot Test

03/29/2014 3:43 PM

garuda777,

All of your posts indicate a complete lack of knowledge of the subject at hand, usually electrical.

Your posts also indicate that you are not a student, but rather someone who is taking a client's money under false pretenses, if not downright lies, as to your competence.

If this hurts your feelings, it should!
Register to Reply Score 2 for Off Topic
truth is not a compromise
Guru

Join Date: Apr 2011
Posts: 7989
Good Answers: 285
#5
In reply to #4

Re: Leakage Current of Hi-Pot Test

03/29/2014 8:29 PM

Lyn: mean for all the right reasons.

__________________
 Eternal vigilance is the price of knowledge. - George Santayana
Register to Reply Score 2 for Off Topic
lyn
Guru

Join Date: Oct 2008
Posts: 42376
Good Answers: 1692
#6
In reply to #5

Re: Leakage Current of Hi-Pot Test

03/29/2014 8:41 PM

I think we all go out of our way to help the people who deserve it.

Register to Reply Score 2 for Off Topic
beentheredonethat
Commentator

Join Date: Sep 2011
Location: Durban South Africa
Posts: 75
Good Answers: 2
#7

Re: Leakage Current of Hi-Pot Test

03/30/2014 12:06 AM

You may find that the cable is actually rated as 11/6.6 kV
Register to Reply
TonyS
Guru
United Kingdom - Member - New Member

Join Date: Aug 2010
Location: Resting under the Major Oak
Posts: 4347
Good Answers: 181
#8

Re: Leakage Current of Hi-Pot Test

03/30/2014 12:35 AM

11KV between what points? Phase to phase you need more than 11KV for reliable withstand tests.

__________________
 The reports of my death are greatly exaggerated.
Register to Reply
3
4wsilver
Power-User

Join Date: May 2013
Posts: 351
Good Answers: 22
#9

Re: Leakage Current of Hi-Pot Test

03/30/2014 12:39 AM

11 KV seems awfully low for a hi-pot test of 6.6 KV equipment. Was the connection point clean conductor? Was the ground properly made? The meter could also be faulty or the test improperly performed. Was this with the other phases grounded and voltage applied to one phase? That is the way it is usually done, and I would expect the test voltage to be higher. 11 KV is somewhat between a high voltage meggar test and a hipot test. The instrument should be verified occasionaly with a know high resistance test device to prove it is reading correctly. I suspect it was not. If it was you should get a reading of current at least while the capacitance builds up and then it should drop to a lower value if it is a DC test. If it is an AC test, the initial will not be as high and it certainly should draw a current with some value due to capacitive coupling, although not as much, at the end of the test. I would suspect either a broken test set or a poor quality one that does not have the correct ranges available. Although not many people do it due to the expense of the equipment, I much prefer the use of power factor test equipment for the insulation, which gives separate values for the resistance, capacitance, and can more accurately tell the predicted life of the insulation structure. It also is considered non-destructive testing like a meggar. The use of a Hipot is considered destructive testing. It will find problems that exist, but after showing a failure, you cannot put the equipment back in service until the point of failure is determined and corrected.
Register to Reply Good Answer (Score 3)
No more Good Answers. Go to first "Almost" Good Answer
Wal
Guru

Join Date: Jun 2011
Location: Phnom Penh
Posts: 4019
Good Answers: 102
#11
In reply to #9

Re: Leakage Current of Hi-Pot Test

03/30/2014 2:10 AM

Echo.

Let's say the OP did perform the test correctly and from experience and learning the OP is doubting the zero reading.....

The OP can check if his instrument is working by measuring the leakage current of a known sample of "poor dielectric" , say a 1MΩ resistor.

At 11kV injection the instrument should read close to 11mA......

__________________
 Difficulty is not an obstacle it is merely an attribute.
Register to Reply
StandardsGuy
Guru
Popular Science - Cosmology - Let's keep knowledge expanding Engineering Fields - Retired Engineers / Mentors - Hobbies - HAM Radio - New Member

Join Date: Dec 2006
Location: North America, Earth
Posts: 4484
Good Answers: 106
#10

Re: Leakage Current of Hi-Pot Test

03/30/2014 12:49 AM

If you doubt the equipment, send it in for calibration or do the performance tests youself from the operating and service manual.

__________________
 “I would rather have questions that can't be answered than answers that can't be questioned.” - Richard Feynman
Register to Reply
IQ
Guru

Join Date: Feb 2013
Posts: 2004
Good Answers: 31
#12

Re: Leakage Current of Hi-Pot Test

03/30/2014 5:12 AM

If you obtained zero leakage on the Hi Pot (Pressure Tester)

1..you obviously have an issue to contend with.

2..You did not test properly.

3..The equipment is not calibrated correctly

4..Your measuring scale is too high

or the leads were not connected to the cable and the test was not in fact conducted on the cable.

Test again and test to the standard for voltages to apply as a 6.6kV cable, if XLPE, with an 11kV applied voltage will show leakage.

What is the cable type? What is the embossing voltage rating on the outer sheath? What is the run length? (11/6.6kV does not mean this is a 'dual' voltage cable). Is this single core or 3 core?

Myself being the client, I would not accept your test results. And, I would be witnessing your set up and testing regime.
Register to Reply
subhash wad
Active Contributor

Join Date: Jun 2011
Posts: 13
#13

Re: Leakage Current of Hi-Pot Test

03/30/2014 9:49 AM

are you using 1 amp meter for current?

sbwad
Register to Reply
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32119
Good Answers: 838
#14

Re: Leakage Current of Hi-Pot Test

11/27/2023 8:46 AM

Yes. The person that designed the <...test...> can, and certainly should have done in the design phase of the <...test...>.

A <...test...> without the pass/fail boundary having been determined beforehand isn't a <...test...>; it's a measurement.

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Register to Reply 15 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

4wsilver (1); beentheredonethat (1); IQ (1); JohnDG (1); lyn (3); PWSlack (2); SimpleMind (1); StandardsGuy (1); subhash wad (1); TonyS (1); truth is not a compromise (1); Wal (1)

Previous in Forum: Regenerative Braking   Next in Forum: Voltage Drop & Cable Sizing

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Electrical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (49 right now)
Show Members
Advertisement