  We present two different approaches to model power grids as interconnected
networks of networks. Both models are derived from a model for spatially
embedded mono-layer networks and are generalised to handle an arbitrary number
of network layers. The two approaches are distinguished by their use case. The
static glue stick construction model yields a multi-layer network from a
predefined layer interconnection scheme, i.e. different layers are attached
with transformer edges. It is especially suited to construct multi-layer power
grids with a specified number of nodes in and transformers between layers. We
contrast it with a genuine growth model which we label interconnected layer
growth model.
