There is indirect PvP aspects in Planetary Interaction, and soon there will be direct PvP aspects with the release of a console game called DUST514.
The indirect PvP aspect is fighting over resources. This was only turned on in some of the later patches in the Incursion. On each planet there is only a limited number of the resources in the ground, which only refill at a certain static rate. The planet will support some (unspecified) minimum amount of resource being extracted, then after that it will deteriorate. This means that too much concentration in the area will deplete the resource for all players pulling that resource out of the ground at that place.
The direct PvP will come later when the DUST514 console shooter game comes out. Exact details haven't been confirmed yet, but the base premise of it is that people playing Eve Online will be able to somehow ask players in DUST514 to somehow disrupt other Eve Online players Planetary Interaction networks.
There are usually two types of Planetary Interaction (PI) setups : Extraction and Factory setups.
With Extraction setups, PI doesn't really require any sort of ongoing ISK costs to run besides export fees of planetary products, therefore all PI here should be "profitable". In High-Sec you won't get very high extraction rates at all, and they will be highly contested, which means not very profitable on a "ISK-per-time-invested" basis. Lo-Sec can be better, but Null-Sec and Wormhole planets can be quite lucrative. There is a larger risk in transporting the PI products from these lower security areas of space though.
With Factory Setups, people can make a fair amount of ISK by making PI setups in High Sec that purely concentrate on turning lower level cheaper PI products bought from the market into higher level more expensive products. You'd need to figure out what is profitable here and what isn't as it would also be quite easy to lose a lot of money doing this if you chose the wrong products, or the sell prices of the high-end product dropped unexpectedly.
In terms of investment of training time, it doesn't take too long to get decent PI skills. Anywhere between a few days for some basic skills to a couple of months to be able to run multiple planets with high level command centres depending on how much PI you want to be involved in.
There's a long thread about probing formations on Fail Heap Challenge here. But to summarise :
Optimal depends on your circumstances.
If signal strength is your target, and time/effort setting up your scanning configuration doesn't matter, then the best layout would probably be either a cube or rectangular antiprism. These two would probably take the longest to set up out of the different kind of arrangements but might be good for scanning down a ship that has been purposely fitted to make scanning a lot harder, previously known as "unprobeable" set-ups.
Usually an Octahedron is a "good enough" balance between ease of set-up and scan strength. It is reasonably easy to make by imagining a compass laying flat where your ship is and launching 6 probes, then drag one of them in each of the directions North, South, East, West, and also one straight up and one straight down. Handily, each of these directions to drag in correspond to the same directions as the positioning arrows around each of the probes.
If time is a telling factor (which is most likely in combat situations) then the regular tetrahedron still works fine, although you may get slighty less scan strength than you did before.
Best Answer
After some research, turns out that a really good way to manage power grid is to stretch the whole colony into a big line.
This way you save power grid necessary to put extractors close to hot spots, with the addition that you have a lot more room to move extractor heads (since the extractor itself is near the hotspot).
I'll accept this answer in few days if nobody else answers.
Source:https://www.reddit.com/r/Eve/comments/5v6v8i/simple_p2_pi_setup_help/