A Stranded Unshielded Twisted Pair Modeling for Online Fault Location using OMTDR-based Diagnosis Sensor

Despite the worldwide use of stranded Unshielded Twisted Pair (UTP) cables, scientific references dealing with accurate calculation of distributed parameters of such transmission lines are generally missing, especially in high frequency applications where skin and proximity effects are present. On the other hand, reflectometry is a high frequency method that relies on wave propagation in a cable under test for fault diagnosis. In this context, this paper proposes a distributed parameters model for the lossy transmission line of a stranded UTP cable including the pitch of twist and frequency dependent effects to evaluate as faithfully as possible the reflectometry response in such cables. The developed model is validated with 3D-electromagnetic simulations using Time Domain Reflectometry (TDR). For online diagnosis, Orthognal Multi-Tone Time Domain Reflectometry is performed thanks to its capacity to control bandwidth and enable sensors fusion. In complex wiring networks, the developed model is performed to evaluate the performance of OMTDR-based diagnosis sensor including a Xilinx Zynq 7010 FPGA, 10-bit Analog-to-Digital Converter (ADC) and Digital-to-Analog Converter (DAC).