Wind farm application
Wind farm application
(OP)
Do people use current limiting fuses in conjunction with switchgear to be able to tackle higher fault currents in Wind Farm applications? If so, are there any disadvantages that make them not very palatable?
Thanks
Thanks






RE: Wind farm application
RE: Wind farm application
Rafiq Bulsara
http://www.srengineersct.com
RE: Wind farm application
In other words, you cannot reduce the calculated available SCC, because you are using a current limiting device upstream. This method is not accepted by any recognized standards. I presume that is what you meant my "tackling" "higher" fault currents.
Rafiq Bulsara
http://www.srengineersct.com
RE: Wind farm application
The breaker or contactor has to be rated for the maximum short circuit current.
RE: Wind farm application
Single phasing is a good point, but probably can be taken care of using a relay to operate the switchgear when this occurs.
RE: Wind farm application
RE: Wind farm application
The typical application is to protect under rated equipment when system additions raise the short circuit levels. We ahve applied them in parallel with a reactor. If a high fault current occurs, the limiter opens and places the reactor in the circuit.
They are probably too expensive for your application.
RE: Wind farm application
ht
RE: Wind farm application
On the other hand, you've never answered my original question, what higher fault currents? You simply don't have that much fault current on the 690V side of the tower transformers, less than 44kA, and the fault current on the high side is heavily influenced by the connection to the transmission system rather than any contribution from the towers.
RE: Wind farm application
This question is not for a problem I am trying to fix at a wind farm. It is more out of curiosity.
So if there is a chance of 50kA fault levels which are possibly very very rare, can a current limiting fuse in conjunction with the 25kA rated switchgear solve the problem than paying a premium for 50kA switchgear.
RE: Wind farm application
RE: Wind farm application
The Clip technology is a different than a standard current limiting fuse. Instead of a thermal fuse element, it has a solid state sensor that measures current and rate of change of current. It only triggers if the fault current is close to or above the setting, say 22 kA for your hypothetical 25 kA equipmetn. Current interruption is done by triggering shaped charge explosives that severe a bus bar, transferring the current to a current limiting fuse.
This technology avoids some of the issues of series rating, but now all.
Is this "legal"? Depends on the AHJ in your area. If the equipment has to be UL listed or equivalent, there will be a problem. Also, depending on your layout, you might need one for every generator pad mount transformer which makes it not economical.