Analysis of High-Frequency Impedance Measurement Techniques for Power Line Network Sensing

A major aspect in power line distribution networks is the constant monitoring of the network properties. With the advent of the smart grid concept, distributed monitoring has started complementing the information of the central stations. In this paper, power line communications modems deployed throughout the network provide a tool to monitor high-frequency components of the signals traveling through a power line network. We propose, therefore, to use them not only as communication devices but also as network sensors. Besides classical voltage measurements, these sensors can be designed to monitor highfrequency impedances, which provide useful information about the power line network, as for instance status of the topology, cable degradation, and occurrence of faults. In this paper, we provide a technical analysis of different voltage and impedance measurement techniques that can be integrated into power line modems. We assess the accuracy of the techniques under analysis in the presence of network noise, and we discuss the statistical characteristics of the measurement noise. We finally compare the performances of the examined techniques when applied to the fault detection problem in distribution networks, in order to establish which technique gives more accurate results.