maintenance requirement for digital relays?
maintenance requirement for digital relays?
(OP)
Hi,
Im doing a small project regarding the maintenance procedure for digital relays for our company, at the moment as per our summary of tasks for digital relays we only test the inputs and outputs cause these relays have the ability for self checks.
Im suggesting for a revision of our summary of task so we can include the testing of the full scheme including the logic behind the operation of that contact.
I need some help from you guys to convince them to include this on our summary of tasks as i have to defend this in front of our bosses... any input would be greatly appreciated...
P.S.
We have encountered at least two relay fails that the self checks didn't pick up for the past 3 years thats why i've decided to have a punt on this one...
Im doing a small project regarding the maintenance procedure for digital relays for our company, at the moment as per our summary of tasks for digital relays we only test the inputs and outputs cause these relays have the ability for self checks.
Im suggesting for a revision of our summary of task so we can include the testing of the full scheme including the logic behind the operation of that contact.
I need some help from you guys to convince them to include this on our summary of tasks as i have to defend this in front of our bosses... any input would be greatly appreciated...
P.S.
We have encountered at least two relay fails that the self checks didn't pick up for the past 3 years thats why i've decided to have a punt on this one...






RE: maintenance requirement for digital relays?
RE: maintenance requirement for digital relays?
The bench test and self-test are a must but they do not check the external wiring to breaker controls.
Rafiq Bulsara
http://www.srengineersct.com
RE: maintenance requirement for digital relays?
Therefore we should ask whenever there is a clame the self test dosen't test everything, what type of relay.
I would expect the inputs, and outputs would not be tested. A meter test, and pulseing the outputs, is a big importance. Also descrete inputs must be tested.
But beyond that, what isen't self tested?
RE: maintenance requirement for digital relays?
RE: maintenance requirement for digital relays?
Solid state relays generally work perfectly if they are set up properly to begin with and nobody "lets the smoke out".
I've been setting and testing them for going on 15 years now and have never seen one that passed initial test fail in service.
RE: maintenance requirement for digital relays?
They are reliable, but our luck has not been quite that good. We have seen a few fail.
RE: maintenance requirement for digital relays?
First off, let's assume you did a very thorough job of checking exterior devices for proper function and you also checked every bit of logic you've programmed, and all that has been working properly. Now you're in service, and problems still come along.
We had relays just quietly die. That got us to start assigning a "common trouble" alarm into the SCADA where heretofore we'd just gone on breaker trip status. We didn't have "critical failure" outputs on the old electromechanical relays. With the new relays you can have several conditions to monitor, some by direct communication to the relay, such as loss of remote device communications, etc., AND you have a set of contacts that tell you that the relay has failed, up to and including loss of power. That contact needs to go to the SCADA and thence to an operator.
I've had more than one case where a test technician inadvertently loaded a different setpoint file into a relay than the one intended.
And as others have pointed out, problems with exterior devices and wiring need to be checked periodically, too.
old field guy
RE: maintenance requirement for digital relays?
RE: maintenance requirement for digital relays?