João Hespanha, a professor in the departments of Electrical and Computer Engineering and Mechanical Engineering at UC Santa Barbara has looked at the vulnerability of links beween sensors in the grid where GPS signals are used to synchronise the timing.
"It is about something much different than your regular computer virus," said Hespanha. "It is more about cyber physical systems -- systems in which computers are connected to physical elements. That could be robots, drones, smart appliances, or infrastructure systems such as those used to distribute energy and water."
In a paper titled "Distributed Estimation of Power System Oscillation Modes under Attacks on GPS Clocks," Hespanha and co-author Yongqiang Wang (a former UCSB postdoctoral research and now a faculty member at Clemson University) suggest a new method for protecting the power grid from attack.
"In the power grid, you have to be able to identify what the voltage and the current are at specific, highly precise points in time" for multiple points along the grid. Knowing the speed at which electricity moves, the distance between sensors, and the time it takes an oscillation to move between sensors, one can determine whether the oscillation is real," said Hespanha.
Making these precise, high-resolution measurements anywhere in the grid is possible through the use of phase measurement units (PMUs) -- devices that are aligned with the atomic clocks used in GPS. PMUs are among the most important devices for monitoring autonomous control systems, they have seen limited use as they are vulnerable to GPS spoofing attacks.
"There is the possibility," said Hespanha "that someone will hack the system and cause a catastrophic failure."
The attack could be as simple as someone taking a GPS jammer to a remote power-distribution station and tricking the system into providing false measurements, leading to a cascade effect as false readings ripple through the system and incorrect actions are taken. Since it is virtually impossible to prevent a hacker from getting