Overhead powerline and water pipeline

First off who has calcualted that?
Pipelines have isolation joints where they come out of the ground if CP is there and there is always an overvoltage protector to the earthed side.
Someone doesn't really know what they are talking about here (IMHO) and creating a problem which doesn't exist.

What sort of "power line"?
Parallel running or crossing at 90 degrees?

But your questions
1- is this minimum distance depends on the liquid service (Oil, Gas or Water)? In other words, can this minimum distance reduced if our pipeline transports water rather than oil or Gas?
What minimum distance?
And no it doesn't.

2- And in case of water transmission line (3LPE externally coated), what is the minimum horizontal distance between a pipeline and overhead powerline supports? Provided that our overhead powerline supports is 60 KV (can anyone please help me with finding a reference for that?)
There isn't one.

3- And in case if the minimum horizontal distance between a pipeline and overhead powerline supports is less than the minimum recommended distance, what can we do to mitigate such a problem?
You employ a good CP engineer and get the pipeline earthed via PCR which lets the /Ac out but keeps the DC in, or run zinc linear anodes / tape all the way in parallel and connect it to the pipe every 100m or so

Look up AC induced corrosion and there are many such systems.

I'm designing one at the moment which runs for >50km inside a ROW with a 400kV OH line. It can be done, but find a good CP man.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Some companies (Saudi Aramco for 1) have minimum clearances to electrical lines depending on
line voltages. When not possible, bonding the pipeline to the electrical towers was considered.

INGAA RECOMMENDATIONS


Mitigation of

Electric txm companies also have their requirements and recommended practices

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

Running in parallel for long distances is something to be avoided if you can, but the distance you need to avoid an issue is in the hundreds of metres if you're running parallel for km at a time and you're looking at high voltage. 60kV is relatively low so 75 to 100 m ad you'll be fine, but you won't find that written anywhere. and parallel for 40km or so and that distance gets bigger.

But pipelines have been crossing under power lines at 90 odd degrees for centuries now without serious issue and the science behind ac mitigation is now pretty good.

Those papers are good - I'll have a better look tomorrow, but there is no such thing mainly as min distances in them.

Aramco just pluck distances out of thin air because they have more desert than god so can say go 100m or whatever, but there are many aspects to this issue and a bald min distance is either not valid in a particular set of circumstances or wildly conservative. IMHO.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

The ingaa document is the best of that lot and the graph on fig 12, p32 shows why setting any sort of distance without knowing the current, voltage and ore importantly ground resistivity is a fools game.

Like I said before, you're looking at between 300 to 500m in the worst case, even for a piddly 6okV system to avoid issues.

But you can deal with the issues, so you don't need any fixed "mandatory" distances.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.