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Suggestion: Try modeling your system in EMTP with your switch opening and see what kind of transients result. If there are no significant overvoltages, try testing that way.

lol...guys, all it takes is clicking on the person's username to see what else they have posted...tmaly1 is obviously for real...check out the other posts. Don't be goofy!

Thanks, jbartos. Anyone had any field experience with these or are they too new?

Hopefully most of you somewhat recall the discussion on substation batteries I initiated (thread238-83460). I have come across another type of battery that I am not familiar with but seems to be a valid choice for replacement of our lead-acid batteries. I would like to get some other opinions...

Why is the transformer necessary? Was the utility unable to find a cap bank that could operate at the nominal 69 kV voltage? There are inherently large transients associated with cap banks, especially during switching. An EMTP simulation should be done to determine the severity of the...

Where is the location of the fault?

dkle40h, Are you saying you are interested in knowing the highest *transient* voltage that the circuit breaker can handle?

and also where was the fault location?

samreye, Could you describe in a little more detail the events that occurred? What type of relay tripped each feeder?

davrom, what did you mean by this: A note to musicguy1800: go get a bier yourself! ??

Our Liberty 1000's are most commonly used in small substations that are primarily distribution substations. These small subs usually have a 10' x 12' panelhouse that contains all the relays and communication equipment, as well as a small office space. This is where our VRLA's reside...

I have a theory, though it may not be correct. I am a brand-new engineer (guys with experience, please help me out if I'm wrong!!). Couldn't one argue that the short-circuit MVA is going to be the same for a fault on the primary side as on the secondary side? If so, then: MVA,sc-primary =...

This is a three-phase transformer?

This is an interesting question. Anybody know? :)

Thanks for all the info. I will check with the manufacturers regarding ventilation considerations for flooded cell batteries and see if it is possible for us to switch over to those from our VRLA's. If you have anything else to add, don't hesitate to post, I am learning a lot here!

The cells we have are not vented. They are VRLA's. They are also generally confined in spaces without much ventilation.

Are there different operating conditions or environment required for flooded cells vs. VRLA's? (e.g. ventilation, temperature, moisture)

The lead-calcium batteries I am referring to are Liberty 1000 Series Lead Calcium batteries. We have installed them in several different locations, not just one, and in every location they have been installed in, they give us trouble. We own many substations with lead-acid batteries that are...

The utility company I work for has several old lead-calcium substation batteries that are badly in need of replacement. I am doing some research to determine if there is another kind of battery that will provide a longer life and less maintenance. The manufacturer claimed that these batteries...