Elimination of Undetectable Attacks on Natural Gas Networks

Natural gas pipeline system operations rely heavily on Supervisory Control and Data Acquisition (SCADA) systems. While the SCADA systems introduce many advantages, they also introduce more vulnerabilities by providing opportunities for malicious cyber-attackers. If the cyber-attacks properly modify pressures, flows, and the topology the operator believes is present simultaneously, the cyber-attacks can be undetectable. While this topic has received attention for electrical grids, other cyber-physical systems have seen much less study on this topic. Natural gas networks are employed extensively to power generators in the electrical grid, so attacks on natural gas networks are very important. We have not seen any research on this topic for natural gas networks yet. The particular nonlinear equations which model natural gas networks make the analysis much more difficult. In this paper, we study undetectable attacks on natural gas networks in a signal processing perspective by describing the steady-state mathematical model and sensor measurements. We propose a countermeasure to eliminate undetectable attacks by protecting sensors in specific locations. We present an example that describes how an operator can be misled if the proposed countermeasure is not applied. In such cases, the operator could apply inappropriate control which could damage the system or cause a loss of critical gas supply to customers.