  In a macro-economic system, all major sectors: agriculture, extraction of
natural resources, manufacturing, construction, transport, communication and
health services, are dependent on a reliable supply of electricity. Targeted
attacks on power networks can lead to disruption in operations, causing
significant economic and social losses. When cyber networks in power system are
compromised, time-critical data can be dropped and modified, which can impede
real time operations and decision making. This paper tracks the progress of
research in power system cyber security over the last decade and presents a
taxonomy of data attacks. Nineteen different attack models against major
operation and control blocks are classified into four areas: steady state
control, transient and auxiliary control, substation control and load control.
For each class, a comprehensive review of mathematical attack models is
presented. The goal is to provide a theoretically balanced approach to cyber
attacks and their impacts on the reliable functioning of the electric grid.
