Medium Voltage Metal Clad Switchgear

[kingtutley]

OK. This question will probably show just how unprepared I am to do my job, but I'm still going to ask.

I am a recent grad with my BSEE, I won't say from where to protect the name of the institution.

I am working as a consultant for the time being.

I want to know more about MV switchgear. In particular, how they operate, that is the logic behind the function. Don't get me wrong, I understand the basic principles, but I need/want more detailed information. For instance, on one of the single-lines I have in front of me there are auxiliary contacts (52x). I have been tld that these are part of the switchgear. I would like to see where they are ON the switchgear. I understand the basics of relays and how the contacts work, but so much is missing from my understanding. Lockout relays are anothyer issue. I am uncertain if my braod question can find an answer here, but, here's to trying. Does anyone know where I can find a generalized diagram of the switchgear with components labeled and functions thereof defined, an overall single-line showing where each of the electrical components fits in (electrically speaking)?

Now, let the blood-letting begin.

 

[Zogzog]

The physical location would be different depending on the manufacture and vintage of the switchgear, those are some pretty broad questions.

You can go to any OEM's website and download the Installation and Maintenence manual for the switchgear and see a physical layout, that would be a good start.

 

[dpc]

I agree with Zogzog. Focus on one manufacturer and review the available literature from them, especially the brochures with nice photos.

You may some find additional info in the IEEE Red Book and the Electrical Engineers Handbook (Fink and Beatty).

 

[catserveng]

I have found the information from Powell to be very good, you might try this link and see if the application guode from there is what you are looking for,

http://www.powellind.com/main/Uploadpdf/pv_ag.pdf

Hope that helps

 

[kingtutley]

The ideas are good, but I have been down this road. Manufacturers aparently believe this information to be somewhat proprietary.

I am not really interested in any particular manufacturer, but rather an understanding of funtion.

As a for instance, the 86 elements on a main breaker lockout the breaker from reclosing without some manual initiative. Ok, HOW are they locked out? What does this 86 do and how does it do it? What part of the breaker mechanism is actually being blocked/locked? What really has to be done to free the breaker? Where are these parts located within the breaker? (I understand this last one will be vendor specific).

A second 'for instance', at least one of the drawings I am working with shows a charging motor. My research indicates that this is for breaker closing/reclosing. How does this really work? What is it doing?

I attribute many of my questions to unknown "smarts" within the gear. Similar to not knowing the programming behind a cell phone, but I still know how the cell phone works. I don't really know how these pieces of switchgear really work. Don't know if that makes it any clearer.

 

[dpc]

There is nothing proprietary in metal-clad switchgear. It hasn't changed much in the past 35 years, other than the change from air breakers to vacuum.

For 86 function, look up Lockout Relay.

The information is generally available. If you have specific questions, you will get answers here.

Cheers,

Dave

 

[Zogzog]

Dpc,

Actually some of the OEM's are now only giving technical documents to the end users.

Kingtutly - The physical operation of an 86 relay differs from manufacturer and vintage so again you need to be more specific. A charging motor charges the closing springs, it is a small motor, like a drill motor, that turns a cam and charges the springs, but dosent close the breaker. It is necessary (Or a solenoid) for remote closing however.

 

[waross]

Here are your device numbers;

http://en.wikipedia.org/wiki/ANSI_Device_Numbers

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[oldfieldguy]

kingtutley--

So you're a new engineer. Here's my advice in reference to your question:

Find out who's working over or commissioning some of the gear you're interested in, and get out there in proximity to it. Look. Ask questions. If you can get with a NETA testing contractor, their technicians can often give you a really good exposure to the 'nuts and bolts' of power equipment to go with the foundation you received in getting your engineering degree.

Don't be embarrassed by your lack of knowledge. Most of the field technicians will be all too happy to get you on the right track and will be happy to help you learn. The last thing they need is another engineer with no idea what's in the real world.

You might have to get yourself in contact with an electrical contractor or a large production facility or an electrical utility or a testing company to find what you need, but I think you'll be better for it.

good luck

old field guy

 

[dpc]

Most of the field technicians will be all too happy to get you on the right track...

No kidding - they'll still be trying do that after you've worked 30 years -

 

[kingtutley]

That is actually what I am trying to do. Thanks. If I can come up with a specific question, I'll post it, but at this point I don't really know enough about this to ask an intelligent specific question.

 

[Zogzog]

Tut, where are you located?

 

[kingtutley]

I'm in Chattanooga, tn.

 

[Zogzog]

I know the guys at a switchgear testing company in Hermitage, TN, maybe you can touch base with them.

 

[kingtutley]

That would be great. Thanks you. I really appreciate that.

 

[Zogzog]

http://www.p-g-t-i.com/

Ask for Mose, see if he would allow you to come along on some testing jobs as an "Intern" to learn what you are looking for.

 

[kingtutley]

Does he know you as Zogzog? Can I drop a name so he knows I'm not just some bozo? Not that you know me by any other status.

 

[Zogzog]

No need (He dosent know Zogzog), just tell them what you want to do and I am sure they will be happy to help you (Unless you work for thier competetion) most NETA companies believe an educated customer is a good customer.

 

[rheikaus]

Tut - You've come to the right place. This group of professionals is helpful, knowledgeable, and patient. I was in your shoes not too long ago, and reading posts on this site continues to enlighten me.

Switchgear is not as complicated or mysterious as it seems as a new engineer. It is basically circuit breakers and buswork, not all that much different from the panelboard in your house. It starts to get more complicated when you add in transformers and protective relaying, but keep in mind that it is simple in its' purpose: to distribute power and provide protection.

I agree with the above replies.
1. Read some manuals. Also, this series below is pretty good:

http://www.eaton.com/EatonCom/Markets/Electrical/Learning/LearningontheGo/101BasicsSeries/index.htm

2. Tag along with a commissioning guy. Commissioning is where you learn it all; relays aren't set right, breakers aren't racking properly, and bus is not aligned when the gear lands at site. Troubleshooting and repair is the best way to get comfortable with the equipment.

3. Continue to read this site and anything else you can get your eyes on.

Good luck, and welcome to the field. They don't teach this stuff in most engineering schools -- they didn't in mine. It's a great field though. You lucked out.