Passive RFID tags for monitoring electrical connection mV drop

A wireless system using passive UHF RFID tags has been designed to monitor, in-situ, the mV drop across powered electrical bus bar and cable connections. This voltage, used as a measure of the connection joint integrity, was wirelessly transmitted to a PC based controller for continuous monitoring of an electrical connection. If the voltage exceeded a predetermined threshold, based on bus bar or cable capacity, an alarm was initiated. The system was demonstrated for a range of current levels and bus bar bolt torques to illustrate the ability to measure mV changes under various conditions. Temperature measurements of the connection surface were compared with tag mV values to show that connection voltage was a more reliable predictor of joint failure than bus surface temperature. Tag design and various tag performance parameters are detailed including tag read range, voltage stability, and operating temperature range.