Sample space of unary topologies

[desktoop]

It's me again🤣🤣🤣

In your paper, you mentioned that there are 11558 possible unary topologies(case118), how can I understand the number 11558?

The operation "merging" or "splitting" on single node are obviously not the same with the operation "disconnect" or "connect" on pair of nodes. If I pick "disconnect" or "connect" on pair or nodes, I think I may have 118*117/2=6903 possible topologies. And 118 possible topologies for "merging" or "splitting"? I am not sure about it.

For "merging" and "splitting", will the system case118 become case117 or case119?

Here is your description:

There are 11,558 possible unary actions (corresponding to single node splitting or merging, compared
to the reference topology)

and:

(a) 50,000 of them are sampled with injections x and the reference topology τ = τ ∅ (all substations in the reference topology), (b) then 100 unary actions are sampled randomly among
the 11,558 unary topologies, as well as 1000 injections x, which
generates the other 100 000 samples.

[BDonnot]

Hello,

I explained this process more into the grid2op notebook you can read here :
https://colab.research.google.com/github/rte-france/Grid2Op/blob/master/getting_started/00_Introduction.ipynb

Basically, we modeled each node in the original grid by being a substation with 2 busbars.
You can connect each element (side of powerline, load, generator, shunt, etc.) to either busbars 1 or busbar 2.

And if you allow to reconfigure 1 substation (what I called "unary change"), you have this number of different way to do it.

Again, do not hesitate to read the grid2op notebook and let me know if you have any other questions.