Hi-Pot & El-Cid

[eyec]

which one to use, when and why?

have a generator off for a scheduled outage and moisture/humidity to high for Hi-Pot. would El-Cid provide condition in place of Hi-Pot?

 

[ScottyUK]

El-CID is a tool for detecting defects within the stator core. Hi-pot is normally confined to winding testing. Were you proposing to Hi-pot the core, and what were you expecting to achieve?

 

[eyec]

a hi pot was scheduled as a "let's take a look at the condition of the windings while the unit is down".

as an alternative to not doing anything i was thinking at least an ElCid might give us info on the core if it can be done under high moisture/humidity conditions.

 

[ScottyUK]

Suggest you talk to one of the specialist generator test contractors - Doble Powertest in the UK, for instance - and get their opinion.

An RSO is another test which you could reasonably carry out, although when you ask about El-CID in high humidity, you may as well ask 'em about an RSO too.

Out of interest, where are you?

 

[eyec]

thanks for the info. the rotor is not being removed so testing is limited at this time. bus couplers were recommended for online monitoring but no decision has been made.

i am currently working for a client in the US that has plants accross the country.

 

[jbartos]

Suggestion: Visit

http://www.vpuc.com/minutes/r102300.htm

for:
The additional test (EI CID) is to verify the condition of the insulating material on the stator (unit was installed in 1954).

 

[jbartos]

Suggestion: Visit

http://www.engnetglobal.com/search/companylist.asp?brandid=1207&brandprodid=2581

http://www.adwel.com/elcid.html

etc. for more info on EL CID.

 

[eyec]

thanks for the info. someone figured while to TG was down they would do something. the main concern was WHAT, if any, testing could be done under hi moisture/humidity conditions.

there was no other concern for generator problems and none existed before it came down for the scheduled turbine outage.

 

[QCE]

Usually a Power Factor or Insulation Resistance Test would be recommended. I personnelly wouldn't do a High Potential Test even with low humidity. Maybe even a fancy Partial Discharge Test.

EL-CID test would not tell you anything about the insulation only tells you if you have a core problem.

 

[edison123]

Measure the PI (10 min IR/1 min IR), to check the winding dryness before any Hipot/Surge test/Partial discharge test. A humid atmosphere doesn't necessarily mean a winding with moisture.

ELCID test checks the core only.