I am new in PostGIS, and I am trying to create connectivity(using topology) between 3 sets of points and polyline to model an electrical distribution network.
Does anyone know how to do this?
The question you're asking is not very specific, and as such, you're probably best off getting started, and coming back to ask questions when you find specific issues.
I recommend you read these as a starting point:
I haven't run through these, and there doesn't seem to be much material online, but that might actually be an indication of how easy it is to do!