I am in a research and a step of it is to create a ppa to add academic files. Due the very low speed internet and the impossibility of transforming ppas hosted in launchpad into public, it must be hosted in the local server. I have tried to follow a tutorial from 2009, but no success. Can someone help me on it?
This is not going to be easy.
As far as I can tell the usage of PPA's is launchpad.net only. So there is no PPA server.
So to answer your question: you will need to run your own Launchpad instance. Lucky for your there is a very lengthy article on this here.
From the link some important notes:
Also have a look at Does anyone have experience with a private Launchpad instance?
A ppa repository is simply (approximately) a APT repository that is managed by launchpad server.
As an alternative, if you don't want to set up a launchpad server (that isn't easy), you could simply make an apt repository, that is more easy and permit you to distribute your packages privately.
You can see other questions about that in askubuntu - How to set up an apt repository.
And from that question, you can follow this guide on how to make a repository. See that you have two options, a simple (easy to follow but no so automatic for users) and an advanced (complex but easy to use for users).