  Microgrids (MGs) rely on networked control supported by off-the-shelf
wireless communications. This makes them vulnerable to cyber-attacks, such as
denial-of-service (DoS). In this paper, we mitigate those attacks by applying
the concepts of (i) separation of data plane from network control plane,
inspired by the software defined networking (SDN) paradigm, and (ii) agile
reconfiguration of the data plane connections. In our architecture, all
generators operate as either voltage regulators (active agents), or current
sources (passive agents), with their operating mode being locally determined,
according the global information on the MG state. The software-defined MG
control utilizes the fact that, besides the data exchange on the wireless
channel, the power-grid bus can be used to create side communication channels
that carry control plane information about the state of the MG. For this
purpose, we adopt power talk, a modem-less, low-rate, power-line communication
designed for direct current (DC) MGs. The results show that the proposed
software-defined MG offers superior performance compared to the static MG, as
well as resilience against cyber attacks.
