Passive and Contactless Complex Power Monitoring of Electrical Systems

Maintaining the reliability of electric power infrastructure is essential for preventing outages, optimizing system performance, and quickly detecting faults across diverse industrial applications. Traditional monitoring methods typically require direct contact with power lines, presenting significant safety issues and creating difficulties in accessing hard-to-reach or buried cables. In some scenarios, the dependency on batteries of these power-monitoring systems can limit their sustainability and reduce their actual applicability. In response to these challenges, this article presents a novel solution: a fully passive and contactless, electric power monitoring system with near field communication (NFC) interface. The proposed system integrates a custom-designed contactless flexible, curved, ac voltage sensor and a Rogowski coil for current detection, combined with a signal conditioning circuit and a digital processing unit. The sensory circuit is energized by the high-frequency signal generated by an NFC reader, which also handles data exchange with the system. Furthermore, the system has been modeled using SPICE software, and metrics for measuring complex power, phase shift, frequency, voltage, and current of electrical systems have been implemented directly on the hardware. Finally, a proof-of-concept has been developed and successfully tested on real electrical loads, demonstrating the system functionality.