Wind Energy

26
Network Perspective of Wind-Power
Production
Sebastian Jost, Mirko Schäfer and Martin Greiner
26.1 Introduction
Power production in wind farms faces fluctuations on various levels. On the
level of a single turbine it is the fluctuation of the wind velocity. The intrafarm
wind flow introduces more heterogeneity. At last, the accumulated power
output of a wind farm itself represents a volatile source for the power grid. It
is this layer which demands for a control of these source fluctuations as well
as those resulting from intragrid power redistribution.
New concepts for such a control can be borrowed from modern information
and communication technologies. With a distributive routing and congestion
control self-organizing communication networks are able to adapt to the
volatile traffic sources and the current network-wide congestion state [1, 2].
As a result network operation becomes very robust. The exportation of these
ideas into wind-powered systems requires to see wind farms as well as the
power grid from the network perspective [3].
This contribution represents a first modest step along this network direction.
It makes use of the critical-infrastructure model proposed in [4],
which describes power grids, telecommunication and transport networks in
abstracted form. The introduction of a load-dependent metric, a concept
which is borrowed from Internet routing, is shown to increase the robustness
of such networks against cascades of overload failures. It also reduces respective
investment costs. Finally, two model extensions are developed, which are
of relevance for a robust interaction between wind-energy sources and the
power grid.
26.2 Robustness in a Critical-Infrastructure Network
Model
The network model of [4] does not distinguish source, transmitter, and sink
nodes. Every node provides/receives flow to/from every other node of the
network with an equal share sif = 1. After generation at node i, the flow