Passive Temperature Threshold Sensors Based on RFID and Shape Memory Polymer for Power System Monitoring

The sensing technology of the power system promotes the deep integration of energy network and data information and helps to build a new type of power system with deep integration of digital and system. It can ensure the stable operation of the power grid. RFID sensors are widely used as passive wireless sensors. While they still face the disadvantage of missing data information when the reader is not actively interrogated. In this paper, a shape memory polymer material is introduced and its thermo-mechanical property of deformation recovery above and below the glass transition temperature is exploited to design a temperature threshold sensor. By measuring the backscatter power of the RFID tag, whether the target exceeds the threshold temperature could be determined. This method can record historical information in a non-electric form when the reader is not actively interrogated, facilitating quick problem solving or troubleshooting. In this paper, a prototype of the SMP material was fabricated using 3D printing technology. And several reader-tag temperature threshold detection experiments at different distances were conducted. The results show that the SMP material recovers its deformation near 60 °C in the reader antenna field range. And the backscatter power amplitude of the two tags is significantly flipped. This validates the feasibility of temperature threshold sensors. When electrical equipment malfunctions lead to high temperatures, temperature threshold sensors can detect the malfunction and solve the hidden problem.