Latency-aware segmentation and trust system placement in smart grid SCADA networks

This paper proposes a latency-aware trust system placement scheme for smart grid SCADA networks. Trust systems are specialized security devices that are deployed to provide cyber protection to supervisory control and data acquisition (SCADA) systems. Their functionalities include firewalling and intrusion detection. They are capable of monitoring both types of traffic, ingress and egress. Only a selected number of nodes are equipped with trust systems due to budgetary constraints. Those nodes are known as the trust nodes. As trust nodes are responsible for distributing time critical messages, it is important to consider the impact of latency in the selection of trust nodes. Network segmentation is a commonly used way of trust node computations. This paper proposes a latency-aware segmentation approach that exploits the graph theoretic properties of minimum spanning trees (MSTs). Numerical results are obtained through case studies for the IEEE BUS 118 test system topology. The results reveal that the proposed scheme is capable of reducing the impact of latency.