Separate Ground Conductor for Over head Collection Circuit

[Engineer1916]

EngTips Friends,
I have a few 35kV collection circuits coming from a PV farm to a substation. A small portion of the collection circuits will be overhead at a canal crossing. I am trying to determine, do I run separate over head ground conductors for the crossings? Or should I use earth as my ground path for the crossings?

The GSU at the substation is solidly grounded so I have high fault current available.

Any recommendation or references would be highly appreciated.

 

[Kiribanda]

Even if you run a separate O/H ground wire across the canal, there is no guarantee that
100% of the GF current is taken by the O/H ground wire. There is always a split factor.
For the safe side, I recommend an O/H ground wire.

 

[waross]

A sky wire to protect your underground circuits from lightning strikes is a good idea.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[DBL-E]

I agree with the previous comments, but wanted to add that it may be beneficial to request the interconnecting utilities standard. They can provide very specific guidance on the transition connections.

 

[bacon4life]

Is your collector system 3-wire with no ground? Unless the crossing is so much taller than rest of the line that it has significantly more lightning exposure, I am unclear why the canal would impact having a forth wire.

 

[waross]

I visualized buried cable with a ground conductor except for the canal crossing.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[davidbeach]

It depends.

Where bacon and I live there's absolutely no value in a shield wire for a short bit of overhead line; heck there's 500kv overhead around here with no shields. But there's places where even 13kV distribution has a continuous shield wire. Like I say, "It depends".

I’ll see your silver lining and raise you two black clouds. - Protection Operations