All the software are free. There is no need to download or to install them, they can be used directly from Internet. You should just go to the link that I have provided in my post.
How it works ?
For example if I take this one: http://hto.schneider-electric.neptune.fr/
And I take the first calculator “Display protection device curve”,
I should just enter the input parameters (left side), click on “Display Curve”
and I have the results in the right side.
Is it better now ? ;)