Method for Detecting Intrusive Sensor Data by Enhanced Multi-Terminal Differential Protection

We propose and demonstrate an enhanced multiterminal differential protection logic used to provide an additional cyber-physical security layer within digital substations resilient to intrusive or abnormal data. The protection scheme is able to utilize sensor measurements from existing protective relays in multiple locations within a high voltage circuit and according to the physical laws of the circuit (e.g. Kirchhoff's Current Law), verify the integrity of both measurements and protection functions. Measurements from each protective relay within the protection zone can be confirmed using existing communication infrastructure. Multi-terminal differential protection measurements and logic are used along with confirmation of a secondary transient logic indicator at each location, from superimposed currents, and securing the protection and control systems against sensor anomalies introduced either deliberately or unintentionally. A notional system is simulated in MATLAB/Simulink with traditional and renewable sources and provides a comparison point between existing multi-terminal differential protection and the proposed method.