Federico Passerini

On the Exploitation of Admittance Measurements for Wired Network Topology Derivation

The knowledge of the topology of a wired network is often of fundamental importance. For instance, in the context of power line communications networks it is helpful to implement data routing strategies, while in power distribution networks and smart microgrids it is required for grid monitoring and for power flow management. In this paper, we use the transmission line theory to shed new light and to show how the topological properties of a wired network can be found exploiting admittance measurements at the nodes. An analytic proof is reported to show that the derivation of the topology can be done in complex networks under certain assumptions. We also analyze the effect of the network background noise on admittance measurements. In this respect, we propose a topology derivation algorithm that works in the presence of noise. We finally analyze the performance of the algorithm in a setup that is typical of power line distribution networks.

Power line fault detection and localization using high frequency impedance measurement

The reliability and quality of electrical power networks are affected by the occurrence of electrical faults. In this paper, we propose a novel method to identify the occurrence of faults in distribution networks, based on impedance measurements performed at the central distribution office. The measurements can be performed using PLC modems that belong to the energy metering infrastructure. The fault is detected by means of continuous impedance monitoring and afterwards its distance from the central office is estimated using the same measurement traces, without requiring additional information. Different type of faults are tested, and the effect of the measurement bandwidth and the electrical noise on the measurement is also assessed.

In Band Full Duplex PLC: The role of the hybrid coupler

In Band Full Duplexing (IBFD) has recently become attractive for power line communications (PLC). In this paper we analyze the role of the first stage of a PLC-IBFD modem: the hybrid coupler. An analytical analysis of its influence on the signal transfer function is performed and some simulations using a measurement database are also included. Possible hardware implementation of a PLC hybrid coupler are finally discussed.

Modeling Transmission and Radiation Effects When Exploiting Power Line Networks for Communication

Power distribution grids are exploited by power line communication (PLC) technology to convey high-frequency data signals. The natural conformation of such power line networks causes a relevant part of the high-frequency signals traveling through them to be radiated instead of being conducted. This causes not only electromagnetic interference with devices positioned next to power line cables, but also a consistent deterioration of the signal integrity. Since existing PLC channel models do not take into account losses due to radiation phenomenon, this paper responds to the need of developing accurate network simulators. A thorough analysis is herein presented about the conducted and radiated effects on the signal integrity, digging into differential mode to common mode signal conversion due to network imbalances. The outcome of this work allows each network element to be described by a mixed-mode transmission matrix. Furthermore, the classical per-unit-length equivalent circuit of transmission lines is extended to incorporate radiation resistances. The results of this paper lay the foundations for future developments of comprehensive power line network models that incorporate conducted and radiated phenomena.

Power line network topology identification using admittance measurements and total least squares estimation

In this paper, we consider the identification of a smart grid network topology by means of admittance measurements performed at the network nodes. We show how the application of the transmission line theory allows the identification of the node-to-node connections. Thereby, a topology identification algorithm is presented. The identification error due to the network noise is reduced by performing repeated measurements, either at different time instants or over a set of frequencies, at each network node. The information is then fused by means of the total least square regression technique, which is also compared to a simpler estimator. A thorough analysis of the results is then presented, which shows good reliability of the proposed algorithm.

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 high-frequency 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.