I am looking for the Ameren and ComED's distribution lines and distribution substations. They are the 2 largest electrical utilities in Illinois. I know the HLIFD data has Transmission lines and transmission substations, but these are 2 different types of systems.
Geoplatform.gov has a Transmission Lines layer available as an ESRI REST Feature Service.
You can view it on ArcGIS online here
View the metadata or download it as an XML file here
Or use the service URL to load it into a GIS program.
Here's GeoJSON version exported from ESRI
Sorry for personal URL, but gist.github.com chokes on the size of it.