  The method of flow tracing follows the power flow from net-generating sources
through the network to the net-consuming sinks, which allows to assign the
usage of the underlying transmission infrastructure to the system participants.
This article presents a reformulation that is applicable to arbitrary
compositions of inflow appearing naturally in models of large-scale electricity
systems with a high share of renewable power generation. We propose an
application which allows to associate power flows on the grid to specific
regions or generation technologies, and emphasizes the capability of this
technique to disentangle the spatio-temporal patterns of physical imports and
exports occurring in such systems. The analytical potential of this method is
showcased for a scenario based on the IEEE 118 bus network.
