A retrofit 60 Hz current sensor for power monitoring at the circuit breaker panel

Improved signal conditioning electronics and new experimental results are presented for a sensor that measures current flow in a circuit breaker. A PIC microcontroller optimizes the phase reference for the synchronous detection system on startup eliminating the need for I/Q demodulation. Ultimately, the parts count of the signal conditioning electronics is halved compared to the previous work. Experimental results are presented demonstrating the sensor´s response to 60 Hz signals with higher harmonic content and to step transients in 60 Hz signal amplitudes. The proposed current sensor does not require permanent modification of the breaker panel or the circuit breaker itself. The intent of this work is to develop a low-cost, non-intrusive, retrofit sensor for centralized power monitoring at the circuit breaker.