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Protection relays coordination

Protection relays coordination

Protection relays coordination

(OP)
Hello folks,

I would like to know if there are softwares helping with protection relay settings coordination? For instance I work in a power plant and our generator is protected by two numerical protection relays from different suppliers(MICOM and SEL). I am trying to verify that the overexcitation limitation (AVR) is well coordinate with the two generator protection relays in order to determine that the limitation is active prior the two protection relays since those will trip the unit.

The only solution I have found so far is using Excel and drawing the curves which is really time consuming.

Thank you

RE: Protection relays coordination

SKM and ETAP are good packages.

RE: Protection relays coordination

Almost all the power system study software now comes with the relay coordination package. Additional names are EDSA, CYME etc.

However, based on my experience, these softwares are good for the over current relay coordination (ground fault included), by drawing very nice curves. You can measure the exact discrimination time interval. If you have any targeted discrimination interval, you can just pull the curves like a rubber band and then see what is the corresponding setting.

For any other settings, I did not find these softwares that useful. But as a marketing strategy every software supplier has some gimmicks to show.

Like, ETAP shows the real time sequence of operation etc. These are not for the working engineers. Only to butter the managers who are the decision makers!

RE: Protection relays coordination

Old school: Engineering graph paper works just as well. Get a copy of the curves from the vendors, and graph them on the graph paper. French curve templates will help. Or, if you're in luck, the vendors curves will be on the same size charts, and you can just place the paper on top of each other and, with a strong light behind, verify the curves.

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RE: Protection relays coordination

Quote:

Engineering graph paper works just as well.

Speaking from a lot of experience, I don't agree with this at all. For coordination of overcurrent devices using time-current curves, I would never want to go back to doing this manually. However for this particular issue, creating the curves manually and overlaying them may be the most efficient approach.

But agree with other comments, that the commercial products I'm aware of are focused on overcurrent coordination. For generator protection, there are too many different approaches to try to standardize in a single software product.

RE: Protection relays coordination

dpc: Yes, you are correct...while graph paper is a valid option, I should not have stated it 'works just as well'. The software packages are much, much better, but just thought if that's not an option, go with the old school method.

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