symbology - Shifting display of overlapping lines in QGIS?

When points are overlapping, there is this property which allow to automatically display the lot of them separately around where they are, called 'Point displacement'. But it doesn't work for lines, even so it seems to me quite conceptually feasable in order to achieve something like that :

I absolutely need to see the differents lines which in reality are all in the same place (I am working in telecomunication networking). The only way I see for now is to really create different lines like in the picture above, thus creating spatial mistakes.

I'm using QGIS 2.14.