Secure electric power delivery system protection during cyber threats
AssigneeSchweitzer Engineering Laboratories, Inc.
InventorsEdmund O. Schweitzer, III, Krishnanjan Gubba Ravikumar, Austin Edward Wade, Tony J. Lee, David J. Casebolt, David E. Whitehead
Life of this patent
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Abstract
Systems and methods may maintain protection of electric power delivery systems in the event of an attack on protection and/or control features of the power system. Primary protective functions may be physically isolated from other functions in primary protection relays. Integrators may facilitate non-primary protection functions and disconnect all communication with primary protection relays in the event of an attack. Primary protection relays maintain protection functions even during the attack or unavailability of the integrators.
Claims18
A system to maintain protection of an electric power delivery system during a cyber-attack, comprising:
- a primary protection relay configured to provide protection to the electric power system, the primary protection relay comprising:
- a power system signal input configured to receive electric power delivery system signals from one or more external elements of the electric power delivery system;
- a protection subsystem configured to determine an operating condition of the electric power delivery system using the electric power delivery system signals and to implement a protective action command when the operating condition is outside of a predetermined operating parameter;
- and
- a protective action output configured to transmit a protective action command to be performed by primary equipment of the electric power delivery system;
- and
- a supervisory system in communication with the primary protection relay, the supervisory system comprising:
- a communication subsystem configured to control communications with the primary protection relay, the communications being distinct from the electric power delivery system signals received from one or more external elements of the electric power delivery system via the power system signal input;
- and
- a kill switch subsystem configured, upon activation following detection of the cyber-attack, to restrict all of the communications with the primary protection relay received via the communication subsystem;
- wherein, after activation of the kill switch subsystem and while all of the communications with the primary protection relay continue to be restricted, the primary protection relay continues to provide protection of the electric power delivery system by continuing to receive and monitor the electric power delivery system signals from the one or more external elements of the electric power delivery system during the restriction of all of the communications via the communication subsystem.
A method for selectively disabling at least one communication path to a primary protection relay while the primary protection relay continues to provide protection to an electric power delivery system using a supervisory system, the method comprising:
- directing, with a supervisory system, communications between a primary protection relay of the electric power delivery system and one or more external devices in communication with the electric power delivery system through the supervisory system, the primary protection relay configured to:
- receive electric power delivery system signals from the one or more external elements of the electric power delivery system;
- determine an operating condition of the electric power delivery system using the electric power delivery system signals and to implement a protective action command when the operating condition is outside of a predetermined operating parameter;
- and
- transmit a protective action command to be performed by primary equipment of the electric power delivery system;
- detecting, with the supervisory system, activation of a kill switch;
- disrupting, with the supervisory system, one or more communication paths between the primary protection relay and the one or more external devices while the kill switch is activated, the one or more communication paths being distinct from the electric power delivery system signals received from one or more external elements of the electric power delivery system by the primary protection relay;
- and
- during the disrupting of the communication path, continuing,
- with the primary protection relay, to provide protection operations by continuing to receive and monitor the electric power delivery system signals from the one or more external elements of the electric power delivery system during the disrupting of the one or more communication paths.
Dependencies are inferred from the claim text.