AHarb
Member
- Location
- Atlanta, GA
Hello,
I work for an EMC and we currently use Cooper hydraulic reclosers with Kearney KS fuses. A coworker and I were looking at the coordination of some of these and noticed there was a coordination issue sometimes at low magnitude faults. An example is we would normally use a Kearney KS 20A fuse below a Cooper 70L (2A, 2B) recloser. I've attached a plot of the coordination with these two devices.
We have also used Kearney QA fuses in the past. For the example above, we looked at replacing the Kearney KS 20 A fuse with a Kearney QA 50 A fuse. This would allow larger loads and maintain better coordination with the slow curve of the 70L recloser. However, at high magnitude faults, the fuse may blow before the recloser trips. So we're losing some coordination at high magnitude faults versus gaining some coordination with low magnitudes faults.
I've attached plots of both for you to view. My question is: Are there any fuses out there that will coordinate better with the Cooper hydraulic reclosers? In a perfect situation, we would want a fuse curve that falls perfectly between the fast and slow curves without ever intersecting.
I appreciate any help.
Thanks.
I work for an EMC and we currently use Cooper hydraulic reclosers with Kearney KS fuses. A coworker and I were looking at the coordination of some of these and noticed there was a coordination issue sometimes at low magnitude faults. An example is we would normally use a Kearney KS 20A fuse below a Cooper 70L (2A, 2B) recloser. I've attached a plot of the coordination with these two devices.
We have also used Kearney QA fuses in the past. For the example above, we looked at replacing the Kearney KS 20 A fuse with a Kearney QA 50 A fuse. This would allow larger loads and maintain better coordination with the slow curve of the 70L recloser. However, at high magnitude faults, the fuse may blow before the recloser trips. So we're losing some coordination at high magnitude faults versus gaining some coordination with low magnitudes faults.
I've attached plots of both for you to view. My question is: Are there any fuses out there that will coordinate better with the Cooper hydraulic reclosers? In a perfect situation, we would want a fuse curve that falls perfectly between the fast and slow curves without ever intersecting.
I appreciate any help.
Thanks.