Methods and systems for detecting compromised sensors using dynamic watermarking

A system comprising:

• a watermarking device comprising:
• an input for receiving an electrical signal;
• a watermark injector circuit configured for injecting a dynamic random watermarking signal into the electrical signal;
• and
• an output for outputting the electrical signal with the dynamic random signal superimposed on the electrical signal to a power distribution system, the power distribution system comprising at least one sensor and at least one power electronic controller configured to use the at least one sensor;
• and
• a monitoring system, implemented on at least one processor, configured for monitoring a sensor signal from the at least one sensor and determining whether the at least one sensor is compromised by sampling real time measurements from the sensor signal, sampling real time measurements from a system model that includes the dynamic random watermarking signal, computing a statistical variance between the real time measurements from the model that includes the dynamic random watermarking signal and the real time measurements from the sensor signal, detecting an increase in the statistical variance, and, in response to detecting the increase in the statistical variance, indicating the presence of a possible attack on the at least one sensor.