Protective Relay Replacement

[dpc]

I have an application for a microprocessor relay to replace an existing ABB (I-T-E) CircuitShield analog solid-state overcurrent relay. But the owner wants something that will fit in the same cutout. I haven't been able to find anything that wouldn't require some cutting.

The existing cutout is about 3.75 inches tall and 6.63 inches wide. The Basler BE1-851 is close, but would require a wider cutout. Same with the SEL-501.

Any other suggestions for a utility-grade digital overcurrent relay that would fit this opening?

 

[davidbeach]

If you want to replace them one for one, with a CT powered solid state relay that uses a microprocessor for the timing functions, look at the Basler BE1-50/51M relays. Very similar to the BE1-50/51B relays that are plug and play replacements for the GE IAC and Westinghouse/ABB CO relays. For the circuit shield, the entire existing relay is removed and the 50/51M, which includes a new case, is installed in its place. While I am a somewhat biased source of information on this, I believe that 50/51B is the only relatively modern relay that fits the hole of the circuit shield. If you want a true numeric relay, with all the features and benefits they bring, you are going to have to do some cutting. In the Basler line of relays, the best way to go from circuit shield relays to numeric relays would be to go with the H1 case for the numerics and remove the sheet metal between two adjacent circuit shields. The circuit shield hole will be about 3.55" high and the H1 would go into a hole 3.5" high.

 

[dpc]

David,

These are three-phase relays. I already recommended the H1 case option as the best alternative, but I'm getting some push back from them due to the panel cutting required, so I wanted to double-check to see if I was overlooking some other option.

Thanks.

 

[davidbeach]

Nope, those folks that got the shaft and wound up with IFC relays or circuit shield relays are SOL when it comes to upgrading to numeric relays without panel cutting. The best thing to do there is to find something that means you only have to make a simple cut, and the simplest cut would be the dividing metal between two existing holes. If you are replacing 3-phase circuit shields (not aware of them, are they the same size as the single phase?), you may not have the ability to join two holes to make one over sized hole.

 

[jghrist]

Are there reclosing relays installed that could also be replaced by the same microprocessor o/c relay? This might be another place to put the new relay.

 

[dpc]

Yes, the three-phase CircuitShield relays are the same size as the single-phase. No reclosing relays - and it's an ungrounded system so no neutral/ground relays either.

There are not as many of these out there as IAC and CO relays, but maybe enough that someone should think about offering a replacement in a similar form factor.

Of course, ABB still sells new CircuitShield relays (along with the CO relays).