Is there a limit?

[Mbrooke]

Is there a limit to how many reclosers can be coordinated in series?

 

[davidbeach]

In theory, perhaps not; in practice, absolutely.

 

[Mbrooke]

What would govern the limit in practice?

 

[mgtrp]

To maintain coordination, your current and time dial settings would get a little ridiculous/impractical.

 

[Mbrooke]

The setting must allow longer fault durations at the reclosers in the beginning of the feeder?

 

[luffy2011]

Relatively longer to satisfy necessary CTI, but should not exceed the time as per damage curve of protected device. Consequently, if there are too many, it will be impractical to achieve coordination. But as to the limit, I haven't read any standard and you can install as many as you want but could be impractical at some point.

How many units are you planning to coordinate?

http://www.powerqualityworld.com

 

[Mbrooke]

Right now its about 6 units but varies upon contingencies. The number is so high because this is a recloser loop scheme. Basically the feeder is broken up into 250 to 1000 customer chunks. Every segment has a normally closed source recloser and a alternate tie recloser.

 

[luffy2011]

That's interesting. Anyway, if ever you encounter a coordination problem, I think you can consider using sectionalizers depending on the intended application.

 

[Mbrooke]

Have you heard of such being done?

 

[luffy2011]

Nah.. In our case, it's already difficult to coordinate more than 4 reclosers. And that's where sectionalizers come in.

http://www.powerqualityworld.com

 

[Mbrooke]

Looks like some of the reclosers will need a sectionalizing responce built in rather than time over current.