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Center for Nonlinear Studies |
A wide area measurement system (WAMS) consists of advanced measurement technology, information tools, and operational infrastructure that facilitate the understanding and management of the increasingly complex behavior exhibited by large power systems. Synchro-phasors or Phase Measurement Units (PMUs) are a technology that offers absolute time-stamped voltage phase measurements and even more detailed voltage profiles at buses in the electricity grid. The first WAMS was installed in 2000 by the Bonneville Power Administration. Only 200 PMUs are already installed in North America. In 2009, the U.S. government announced an investment of 3.4 B $ in energy grid modernization. This investment will include the installation of more than 850 PMUs that will monitor the complete U.S. electric grid. Static-state estimation is a well-known and widely used technique for determining optimal estimates of phase angles ? from noisy real power P, reactive power Q, and voltage magnitude V measurements at generator and large substation buses. This technique permits monitoring the relative phase angles between adjacent generators. Large changes in phase angle between two generators is an early indicator of transient stability problems. Phasor Measurement Units sense the relative phase angle between generators directly and transmit them to a data aggregator. It is crucial to identify any attacks that change PMU measurements since PMU data is used directly and critically for monitoring the power system. In this talk I will begin with a brief survey of cyber security for physical systems. I will then present a taxonomy of cyber-attacks on PMU systems. Following this, I will briefly review WAMS systems and applications. Then, I will present some preliminary research ideas on how to detect integrity attacks on the devices. These attack detection algorithms are based on checking for consistency of the [possibly] corrupted data against the underlying physical models that constrain the phase measurements. The consistency checks are based on static state estimation. I will offer some synthetic simulation results, and close with a discussion of computational and implementation issues that require further exploration.
Host: Misha Chertkov, chertkov@lanl.gov, 665-8119 or the institutional host Frank Alexander, fja@lanl.gov, 665-4518.