Relay Logic

[Pam60]

Hi All,

I just started a new position at a intermediate level in a electric utility. To my surprise the environment is completely different than I expected, it is probably more
cold hearted than a consulting environment but that is besides the point now I just have to deal with it for a better pension plan and medical benefits and 35 hrs week. It is a LDc actually.

Here is the issue, I have been asked to study SEL relay and unfortuntely I have been using GE relays all this time. Now my job will be to go with P&C techs to go substations and see the relay logic they have done on their own and see if it makes sense.
What I was wondering, people like your self, how would this work. Most of the feeders are 13.8 or 5 kV outgoing feeders and I have to make sure it fits the protection philosophy.

What is the relation betweek P&C tech and an engineer and how much I need to listen to them. I dont want them to take me for a ride.
I just have few years of experience and little shaken by this upfront assignment.

I would appreciate any comments to handle a situation like this.

Thanks

 

[davidbeach]

Sounds like a great assignment, no better way to learn about your new system. Every utility structures things a bit differently, so there is no telling what the relationship might be like, but you can always improve it. Use the techs as your eyes and ears; find out what they like and don't like about the present system. Sounds like the company doesn't have a database of relay settings, so that would seem to be your first goal - download the settings from every relay. Spend a day or day and a half a week in the field and the rest of the time in the office analyzing the settings, checking them against available fault currents and the like. Develop standard logic and issue revised settings as necessary. SEL logic seems to be pretty straight forward, particularly if you aren't faced with the SEL-451 as a distribution relay. (But then I've been working with SEL relays for over 6 years now.)

 

[Pam60]

Thanks davidbeach. Great advise.

In case of GE UR relays, their manual take you directly to Enervista Settings one by one and explain you the meaning of each settings and a brief example the way it should be.

I will be working with SEL 451 but There are four manuals for SEL 451 on website, what SEL is trying to prove by this rather than by just giving one standard settings, operation and installation manual.

How do I figure this out ?

 

[alehman]

SEL relays can be a bit intimidating at first, I suppose partially because they they try to be very flexible. You need to dive in and spend some quality time with the manuals. Some of their manuals are subdivided into sections so you don't have to download the whole thing. That may be what you're seeing.

Once you learn the language, they are all somewhat similar. I've heard their classes are very good, if that's an option for you. Phone support is also good. My introduction to SEL was the 300G generator relay. Talk about intimidating! It took a few weeks to get my head around it.

This really sounds like a great opportunity. Remember though that you are the "new guy" for a while, so listen carefully to what other have to say. Once you get a handle on the situation you can start offering feedback.

Alan
“The engineer's first problem in any design situation is to discover what the problem really is.” Unk.

 

[davidbeach]

Ouch, I wouldn't want start with the 451, but some times one doesn't get to pick and choose. First a bit of good news; the instruction manual (IM) consists of the user guide (UG), reference manual (RM), and the application handbook (AH). So all you need is the IM.

Use SEL's AcSELerator software rather than trying work with a terminal program. There is help for every setting in AcSELerator. I'd also spend time with the RM portion. SEL's field application engineers can also be quite helpful.

 

[jghrist]

The IM will have examples of logic for different applications. The SELogic is very flexible and is not that difficult, especially if you start with schemes that are covered in the IM. AcSELerator software has a module that allows you to create SELogic equations by creating logic diagrams. I haven't used this because I've done logic with other relays that have to be done by creating logic diagrams. I find writing the SELogic equations directly to be a lot easier than manipulating graphics.

 

[cranky108]

The SEL 451 should be simple set up for distribution application, unless the person who set it up had an ego complex. Just take it line by line, and look up each element.

Most likely they should be set up simularly.

 

[davidbeach]

The graphical logic in AcSELerator is not available for the 400 series relays; sure wish it was though.

 

[marks1080]

When dealing with techs remember that people are people. I've met techs that know more than engineers and vice-versa. do not approach people with the attitude that you are an engineer and they are techs so you are above them. Treat them with respect and it might be returned. If it isn't, don't worry, just try to make sure the job gets done correctly. If something goes wrong the engineer will usually take responsibility over the techs.

If you don't understand something don't pretend that you do. Take the time to learn the concepts and how the relay works. The SEL can be very tricky, but like anything else, it is managable when you take the time to understand it.

 

[kworkman]

Being new to relays of any type is always very challenging. A bit like learning a new language. Some great advice given here.

The SEL 400 products are the most advanced we (I work for SEL) make. Unlike most of our other relays, they're capable of not only logic programming, but full math programming in a very free-form fashion. As mentioned above, this is mainly to meet the needs of some of our power users out there.

Luckily, for most basic functionality, you don't have to get into that kind of detail. Our Application engineers will be able to help you wade through it the first time or two.

If you're looking for training, as mentioned, we have a division of SEL called SEL University (SELU). I am one of the instructors in SELU. We don't have a class specifically on the SEL-451. We do have an APP 421 course that covers the SEL-421 relay in detail. The SEL-421 is identical to the SEL-451 in logic and programming capability, however is deisgned for transmission, so the course will focus a bit more on distance protection, etc. It would give you great experience with the relay interface and settings process though. I think the next offering of that course is in March. (I'm not trying to break forum policy and sell here, just trying to let you know what is out there and how it might help.)

Good luck, and be sure to follow the great advice given here by our peers on the engineer/technician relationship. The more friends you have in the long run, the better.

 

[Ohmly]

It sounds fairly similar to my role too.
My advice (for what it is worth) is to know what is important and make sure the proposed logic fulfils this requirement.
Test the settings yourself if you have access to the necessary equipment.
I have a view that it doesn't matter what your position is, treat everyone as if they know what they are talking about until they prove otherwise.
What I have found is most people in the protection game are not looking to take you for a ride.
Anyone who has been involved in a protection mishap knows just how bad the feeling is, and would not want this to happen to others.
Only arrogant people may be taken for a ride - just don't be one of them and you should be fine.
It is funny - at our company we used SEL relays for a while before starting to use the UR relays - and most of us find the SELs easier to use!

 

[racobb]

As you have already seen here, most if not all believe the SEL relays to be very powerful with extremely good functionality, and that in itself breeds complexity.

The factory is great and so are their field techs located all over the country.

My advice would be to decide what you need from the particular relay, do your homework, and absolutely do not hesitate to call support.

At least from my experience they are superb!

The biggest thing for me with the relays is making sure I get the I/O logic correct. You have to select your trip output logic carefully, and if not careful it can be overlooked and have you scratching your head trying to figure out what is wrong.

Good luck with it!

Alan