Energy systems are becoming more complex due
to increased coupling between different networks, resulting in multi-carrier
energy networks. Conventional models for the separate networks are not able to
capture the full extent of the coupling. Recently, different models for multi-carrier
networks have been proposed, either using the energy hub concept or using a
case specific approach. Although the energy hub concept can be applied to a
general integrated net- work, it is unclear how the energy hub should be
represented in the graph of the multi-carrier network. This paper presents a
graph-based framework for steady-state load ow models of multi-carrier energy
systems. Furthermore, the effect of coupling on the integrated system of equations
is investigated. The proposed framework is tested on two small multi-carrier
net- works, for comparison with models in literature. Results show that our
framework is applicable to a general system, and that it generalizes both the
energy hub concept and the case specific approaches.