Systems and methods for independent self-monitoring

A method for supervising an intelligent electronic device (IED) comprising protection logic to provide a protection function using stimulus inputs from an electrical power system, the method comprising:

• receiving stimulus inputs from the electrical power system at a monitoring device;
• combining two or more of the stimulus inputs into a composite value, the composite value configured to be non-zero under normal operating conditions in the electrical power system;
• calculating a delta of the composite value;
• detecting a disturbance in the electrical power system when the delta exceeds a threshold, wherein the disturbance is detected by the monitoring device independently of the protection logic of the IED;
• and
• supervising the protection function of the IED based on the disturbance detection.

A system for supervising an intelligent electronic device (IED), the IED comprising protection logic to perform a protection function using stimulus inputs from the electrical power system, the system comprising:

• a monitoring device comprising,
• an input module to receive stimulus inputs from the electrical power system and to combine the stimulus inputs into a composite value such that the composite value is non-zero during normal operating conditions in the electrical power system, and
• supervision logic to calculate a delta of the composite value, to determine an adaptive threshold corresponding to a noise level in the stimulus inputs, and to open an operating window when the delta exceeds the adaptive threshold, the supervision logic being isolated from the protection logic of the IED,
• wherein the monitoring device suppresses the protection function outside of the operating window.