Compromising Security of Economic Dispatch in Power System Operations

Power grid operations rely on the trustworthy operation of critical control center functionalities, including the so-called Economic Dispatch (ED) problem. The ED problem is a large-scale optimization problem that is periodically solved by the system operator to ensure the balance of supply and load while maintaining reliability constraints. In this paper, we propose a semantics-based attack generation and implementation approach to study the security of the ED problem.1 Firstly, we generate optimal attack vectors to transmission line ratings to induce maximum congestion in the critical lines, resulting in the violation of capacity limits. We formulate a bilevel optimization problem in which the attacker chooses manipulations of line capacity ratings to maximinimize the percentage line capacity violations under linear power flows. We reformulate the bilevel problem as a mixed integer linear program that can be solved efficiently. Secondly, we describe how the optimal attack vectors can be implemented in commercial energy management systems (EMSs). The attack explores the dynamic memory space of the EMS, and replaces the true line capacity ratings stored in data regions with the optimal attack vectors. In contrast to the well-known false data injection attacks to control systems that require compromising distributed sensors, our approach directly implements attacks to the control center server. Our experimental results on benchmark power systems and five widely utilized EMSs show the practical feasibility of our attack generation and implementation approach.

I. Introduction

Critical national infrastructure has become increasingly complex. The power grid exemplifies a cyber-physical infrastructure, with data collected from its physical components and processed by control algorithms running on computers to provide for accurate and safe monitoring and control. Such a large-scale trusted computing base introduces a hard-to-protect attack surface. Events such as proliferation of the Stuxnet worm [10], the coordinated attack on the Ukranian power grid [5], and the emergence of new threats that leverage existing weaknesses in these systems [23] demonstrate that cyber-physical infrastructures are unprepared to maintain their safe and secure operation in the face of malicious adversaries.