Given the recipe format changes in 2.0, I'm not sure how this would have ever worked as the recipes use the deprecated format from 1.x.

data.lua should read as below for the mod to actually work:

--data.lua

data.raw.recipe["medium-electric-pole"].ingredients =
{
{type="item", name="copper-plate", amount=1},
{type="item", name="steel-plate", amount=2},
{type="item", name="iron-stick", amount=4}
}

data.raw.recipe["big-electric-pole"].ingredients =
{
{type="item", name="copper-plate", amount=2},
{type="item", name="steel-plate", amount=5},
{type="item", name="iron-stick", amount=8}
}

data.raw.recipe["substation"].ingredients =
{
{type="item", name="copper-plate", amount=3},
{type="item", name="steel-plate", amount=1},
{type="item", name="advanced-circuit", amount=5}
}