  We investigate the vulnerability of a power transmission grid to load
oscillation attacks. We demonstrate that an adversary with a relatively small
amount of resources can launch a successful load oscillation attack to
destabilize the grid. The adversary is assumed to be able to compromise smart
meters at a subset of load buses and control their switches. In the studied
attack scenarios the adversary estimates the line flow sensitivity factors
(LFSFs) associated with the monitored tie lines by perturbing a small amount of
load at compromised buses and observing the monitored lines flow changes. The
learned LFSF values are used for selecting a target line and optimizing the
oscillation attack to cause the target line to trip while minimizing the
magnitude of load oscillation. We evaluated the attack impact using the COSMIC
time-domain simulator with two test cases, the IEEE RTS 96 and Polish 2383-Bus
Systems. The proposed attack strategy succeeded in causing 33% of load to be
shed while oscillating only 7% of load in the IEEE RTS 96 test system, and full
blackout after oscillating only 3% of the load in the Polish test system, which
is much smaller than oscillation magnitudes used by other benchmarks.
