Electroswitch Smart Nameplate for coil monitoring

[teachme2009]

I have recently become interested in adding coil monitoring to my utility's lockout relays. This seems like a simple but necessary thing to monitor, but I don't have a simple answer for it. While researching it, I came across a few options--one from Areva, one from ABB, and one from Electroswitch. All I am looking for is an alarm to SCADA in order to alert us of the condition, so I think that the Electroswitch Smart Nameplate on the lockout relay would be sufficient. It has a contact to alarm if the coil circuit is open. It also provides a true continuity check for the coil. Between this and a loss of DC relay I feel this will provide us with good coverage on our lockout relays. Does anyone have experience with this setup? Is there a better way that I am overlooking? While I don't like to do make work or over complicate things, I also don't want to be the one explaining that our protection didn't operate because of a failed lockout relay that could have been found and repaired before a fault. Any tips or insight is greatly appreciated.

 

[trosepe]

I have used the Electroswitch unit for several years now and have had excellent results. I have seen one coil open and the switch annunciated the open as designed. The assembly is very robust.

 

[davidbeach]

The simplest approach is to put a relay input in series with the coil you want monitored. Enough current will bleed through the input to test the continuity of the coil without activating it. Done all the time for trip coil monitoring.

 

[teachme2009]

Thank you for the replies.

davidbeach -- when you say to put a relay input in series with the coil, are you referring to an input on a microprocessor relay (i.e. SEL) or a simple "ice cube" type relay?

 

[dpc]

An even simpler approach is to put an indicating light in series with the coil and mount it above the LOR. This has been common practice for the last 80 year or so.

Of course, this only works when someone is there to see that the light is out, etc, etc, but it is very simple to implement.

"The perfect is the enemy of the good." -- Voltaire

 

[cranky108]

I would trust a protective relay input above that of an ice cube relay.

The light idea also works, but a device called a RAW relay from E-max also provides a contact.

 

[dpc]

I don't have any problem with the Electroswitch approach - I think it should work fine.

"The perfect is the enemy of the good." -- Voltaire

 

[cranky108]

Are you only concerned about the lockout coil, or the whole circuit?
Measuring at the lockout will tell you that the lockout coil is good. However, if you measure at the protective relay location, you will also be measuring more of the whole circuit.

Probally more of a concern for long circuit paths.

 

[teachme2009]

I am mainly concerned just with the coil itself. The devices which trip the lockout handle are all located in the same panel, other than sudden pressure on the transformer. I think we will go with monitoring the contact on the electroswitch on newer installations and I'll investigate the RAW relay for older installations. Thanks for the feedback and tips.