Solving the Power Flow problem on Integrated Transmission-Distribution Networks: A Review and Numerical Assessment

Abstract

Power ow simulations
form an essential tool for electricity network analysis but conventional models
are designed to work on a separated transmission or distribution network only.
The continuing growth of electricity consumption, demand side participation,
and renewable resources makes the electricity net- works co-dependent.
Integrated models incorporate the coupling of the net- works and interaction
that they have on each other, representing the power ow within this changing
environment accurately. Several numerical methods are available to solve the
power ow problem on integrated networks. They can be categorized as a untied or
as a splitting method and networks can be modelled as a homogeneous or hybrid
network. In this paper, we review and assess these methods on the network
models by running simulations on small test networks and comparing the outcome
on their numerical performance, ie on convergence rate and CPU-time. The re- view
shows that the convergence rate is comparable for most of the methods, but that
hybrid networks have a slight advantage in computational time. Realistic
network models, running on millions of buses and with large distribution networks,
should give a better insight into the speed of the computations.