SEL-351 Feeder protection

[tctctraining]

I have industrial protection background, but never have done settings for a utility protection specifically for this project that I am working on.
A feeder has a recloser and I need to set the breaker to protect the feeder. I apprecite any input on where to start and what to watch for.

Thanks

 

[alehman]

My normal procedure would be to discuss this with the utility's protection engineer. They will usually provide recommended or required maximum overcurrent protection settings for your main.

At the same time I would ask for their time-current curves and attempt to coordinate your main with the utility protection. The recloser may have different TCC's for each reclose attempt.

http://www.sandc.com/webzine/pdfs/ConservativeMethod.pdf

 

[tctctraining]

Well,utility has asked distrubution company to provide them with settings for breaker to provide distribution line protection. I work for consultant hired by distrubution company to setup main breaker for utility.

There is a recloser on the line and main breaker at the TS is SEL-351. So I need to come up with settings for the breaker when recloser is on line and when recloser is off service.

 

[jghrist]

Coordinating with the slow curves of a line recloser is the same as coordinating with any downstream device. The line recloser will trip once or twice on a "fast" curve, then trip on a "slow" curve until lockout. You don't want the main breaker to trip when the recloser trips on its "fast" curve. To avoid this, use "sequence coordination" which is explained in the SEL-351 manual (Close and Reclose Logic section).

 

[cranky108]

jghrist, have you had good luck with "sequence coordination"? I haven't because I have evolving faults which pickup the lower recloser, without counting on the upper recloser.