Revealing unidentifiable attacks in power systems using angle modulated particle swarm optimization and dormant measurement techniques

The power system is a crucial infrastructure which supports computer systems that affect many aspects of our daily lives, and thus a constant target of hackers' malicious attacks. An unidentifiable attack is a new type of bad data injection attack on power systems that confuses the control center software by manipulating measurement data so that there exist multiple feasible solutions for state estimation and thus no deterministic state estimation solution can be produced. To reveal and defend against this type of attacks, these multiple feasible solutions must be solved in advance. This paper proposes a fast and reliable algorithm to reveal such unidentifiable attacks. The algorithm combines the angle modulated particle swarm optimization (AMPSO) and the dormant measurement technique. The AMPSO is employed to reduce the complex high-dimensional binary search problem defined in discrete space to a simple four-dimensional search problem defined in continuous space; the dormant measurement technique is used to avoid repeated computation of state estimation. Simulation results using the IEEE 14-bus and 30-bus systems show that our proposed method produces multiple feasible solutions fast and reliably.