New utility engineer; looking for a good overview of distribution

[atlbraves49]

I got a job with an Electric Utility company and haven't been given a ton of direction/training, and am finding I'm having to study/train on my own to understand the various parts of the distribution system. I've looked at several websites and powerpoints that give BROAD overviews, but am looking for something that digs a little deeper into the specifics. Especially when it comes to overcurrent and overvoltage protection (arresters, cutouts, fuses, etc).

Are there any good resources you guys can recommend?

And for a quick specific question: When an arrester successfully diverts lightning to ground, protecting the device it's in parallel with, once the lightning surge is over, the arrester returns to its normal high-resistance state? I've read about some arresters blowing a charge out the bottom but am unsure when this actually occurs, and under what circumstances.

 

[DTR2011]

Here is a good place to start. FAQ

 

[DTR2011]

Specifically, the Cooper Book would probably be a good start. Cooper Electrical Distribution System Protection Manual

 

[atlbraves49]

Thanks, that Cooper book is actually one I've been going through right now. Very informative.

 

[magoo2]

As far as your arrester question goes, distribution arresters are usually equipped with an isolator. The isolator is heat activated. It is designed to handle situations where the arrester gets overloaded which could happen if you encounter an overvoltage that exceeds the arrester TOV capability or gets enough lightning activity that some of the blocks short out.

My good buddy Jonathan Woodworth has an excellent site on arresters. Search for Arresterworks. I'm sure he's got material on this.

 

[magoo2]

Many of the isolators use a 22 cartridge. This blows out the bottom and disconnects the line lead from the arrester thus removing it from the circuit.

 

[magoo2]

I should have said the isolator disconnects the ground lead from the arrester.

 

[juleselec]

The book by Bayliss and Hardy is very practical and useful for someone starting out:

http://www.amazon.com/Transmission-Distribution-Electrical-Engineering-Edition/dp/0080969127

 

[111R]

The Lineman and Cableman's Handbook provides good, basic explanations and illustrations.

 

[darrellwilson1020]

A copy of the IEEE Red Book "Electric Power Distribution" would be a useful tool.

 

[atlbraves49]

Thanks for all the book recommendations. I intend to look into them.

Magoo2, when the .22 isolator disconnects the ground lead, after the arrester experiences a surge that overwhelms it (from my understanding), that means the arrester is no longer functional (since it can no longer divert the surge to ground), and that the device it's protecting is now unprotected from overvoltage conditions; correct?

 

[magoo2]

That is correct. The arrester normally fails in a short circuit. Without the isolator, it could cause a fuse to blow or lockout a recloser. The isolator has a time current characteristic that falls below the fuse characteristic.

Once it takes the arrester out of the circuit you have no protection after that.