Relay Coordination Study?
Relay Coordination Study?
(OP)
I am a younger, inexperienced electrical engineer, and have been asked to (at my job) look into requirements of a relay coordination study. I am aware of what a relay coordination study is, but do relay coordination studies (to be accepted by inspectors or utility companies) need to be stamped by a professional engineer ? Or is there ever a scenario in which a non PE (but has his FE and a BS in Electrical engineering) can perform a study?
Thanks!
Thanks!






RE: Relay Coordination Study?
RE: Relay Coordination Study?
If you're in USA, you'll do well to get this and an arc-flash study done at the same time.
old field guy
RE: Relay Coordination Study?
That being said, this is a question in general.. there isn't a specific job or location I am trying to do a study for yet. I have found some articles that mention a typical relay coordination study comes down to One-line diagram (showing conductor, transformer, and other ratings of motors etc), Short-circuit study, current scale selection (show the time coordination is achieved), and other information as well.
My questions about this boil down to two:
1) Are most jurisdictions going to mandate an relay/protective coordination study be signed/sealed by a registered PE?
2) Are there certain items inspectors are always going to want to see with a coordination study? (Like one-line, characteristic curve, etc)
Thanks for any help
RE: Relay Coordination Study?
Here in Ontario, utility-owned substations with a largest voltage <50kV require engineers seal, whereas >50kV does not (don't ask, its a long story).
Customer-owned facilities need a seal when first built, but not necessarily when being upgraded or updated.
Next province over in Quebec or Manitoba, no seal is required, but one must follow 'good utility practices'.
So I do not think that there can be a 'general' answer.
RE: Relay Coordination Study?
If you do this and get it wrong then there are two likely outcomes when the protection scheme is needed to do what it's there for and doesn't work properly:
1. More widespread indiscriminate tripping on the network, greater disruption, loss of customers etc., or:
2. What should trip doesn't, risking damage to plant, equipment or even personnel.
I don't think that many utilities would thank an inexperienced engineer for such an outcome because he felt like having a go at it himself and save the utility a bit of cash!
RE: Relay Coordination Study?
RE: Relay Coordination Study?
Please take tomatge's advice to heart. I think it would be fine if you would work with an experienced engineer on this, but relay settings are not something to undertake on your own. You may understand the principles involved, but there are many nuances and "gotchas" that present opportunities for serious error.
Alan
The engineer's first problem in any design situation is to discover what the problem really is. Unk.
RE: Relay Coordination Study?
RE: Relay Coordination Study?
We are based in Canada, Quebec and we perform protection coordination studies for various clients. By law, such work is to be performed by registered engineers with proper professional insurance coverage.
I would recommend that you first acquire experience before performing studies in house. Doing protection work in house is a good practice since you will have first hand information and could then redo your coordination and arc flash studies when there is any changes. If there is no other eng. in house, you can hire external firms for coaching or require to work with them on a couple of studies. We do a lot of expertise transfer with our clients.
Hope this helps!
Daniel D
RE: Relay Coordination Study?
RE: Relay Coordination Study?
RE: Relay Coordination Study?
Also there is the PE issue, several people asked about your location as that will determine if a PE is required.
RE: Relay Coordination Study?
Possession of the tools, whether software or paper, is only a small part of the process. Gathering system data is a second. Putting the two together, if you've never done one before, is time to get expert assistance. this applies for either method, hand or software.
old field guy
RE: Relay Coordination Study?
RE: Relay Coordination Study?
RE: Relay Coordination Study?
http://www.cdeep.iitb.ac.in/nptel/Electrical%20Eng...
RE: Relay Coordination Study?
Check the following IEEE standard for coordination study: IEEE Std 242-2001, IEEE Buff Book. All the good information/advise in this post is discussed in detail the Buff book.
Good luck!
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