battery sizing profile help

[Sn00ze]

hello.

I have a client who has 4 25kV feeder breakers connected to the 138kV bus via a ganged sw and a single 138kV main line breaker.

when sizing the battery bank he wishes to not do a "worse case" scenario. he wants to open and close ALL breakers after 16 hours.

This is a new one for me, so i would appreciate some insight.


The way i see it I usually size them based on the miunte "duration" which has the longest/biggest current draw. So....

Do you size by saying ALL breakers will trip at once during the first minute? steady load for 958 minutes then close/trip on the last one?

or do you:

trip all at once then spread the closing and second trip/close over 2 minutes per breaker?

 

[bacon4life]

Hopefully the client actually wants an open/close/open cycle; an open/close cycle without being able to open on fault could be catastrophic. For blackstart restoration, we would typically open all of the breakers with the substation dead, energize the transmission line and then close the substation breakers. Particularly during wind storms feeders are likely to have a fault during the first restoration attempt.

All breakers should definitely be able to trip simultaneously. If the battery system provides the energy for charging the stored energy system (i.e. spring/hydraulics), then it is like some of the breakers might do a close/trip cycle while other are still charging.

 

[Sn00ze]

Hi Bacon4life,

The client wishes to be able to close/open TWICE on batteries.

So, you are saying that the profile would see in 1 minute all breakers tripped. the second minute all breakers closed (Sprg charging). and repeat once more for a total of 4 periods?