Series arc faults in AC and DC electrical circuits. Characterization and detection methods

This paper analyzes the problem of the arc faults in both AC and DC low voltage electrical circuits. The state-of-the-art of the arc fault detection methods is analyzed together with the UL 1699 and UL 1699B Standard requirements for protection devices against arc faults (AFCIs). An experimental characterization is carried out of the arc fault phenomenon, for both AC and DC systems, focusing the attention on series arcs. The experimental measurements are carried out on a proper test bench, which has been developed in order to reproduce significant arcing conditions, in accordance with the UL 1699 Standard requirements

ARC FAULT DETECTION EQUIPMENT AND METHOD USING LOW FREQUENCY HARMONIC CURRENT ANALYSIS

An arc fault detection circuit includes a current sensing circuit coupled to a line conductor carrying a current. The current sensing circuit operates to sense current and output data indicative of the sensed current. A processing circuit implements a frequency transform algorithm to transform the output data to frequency data in a low frequency range and with a high spectral resolution where a minimum short time observation window is concerned. The processing circuit identifies an arc fault condition on the line conductor by identifying differences in said frequency data between at least two subsequent observation windows and identifying characteristics which exceed thresholds

Real-Time System based on a Neural Network and PID Flight Control

The modern flight control systems are complex since they have a non-linear nature. Also, modern aerospace vehicles are expected to have non-conventional flight envelopes and, in order to operate in uncertain environments, they must guarantee a high level of robustness and adaptability. A Neural Networks controller can be used in applications with manned or unmanned aerial vehicles. The paper shows the mathematical model for hexacopter dynamics and a comparison between two different technique for stabilization and trajectory control: proportional,integral, derivative controller and real rime system controller based on Neural Networks. Numerical simulations are performed in order to validate both mathematical model and control approaches

A New Low Cost Coupling System for Power Line Communication on Medium Voltage Smart Grids

This paper proposes and verifies the performance of an innovative and low cost coupling system for power line communication (PLC) on medium voltage (MV) smart grids. The coupling system makes use of the capacitive divider of the voltage detecting systems (VDSs) to inject and receive the PLC signal. VDS are usually already installed in the MV switchboards of the major electrical manufacturer all over the world according to IEC 61243-5. VDS are used to detect the presence of the mains voltage to guarantee personnel safety. An interface circuit has been developed to be connected between the PLC transceiver and the VDS socket. In this way, the PLC signal can be coupled to the MV network without installing a dedicated MV coupler, thus avoiding the related costs of the coupler, the installation, and the temporary service interruption. The innovative device is able to couple digitally modulated narrowband PLC signals with modulation rate up to 19.2 kbit/s. In this paper, first a description of the proposed solution is reported. Second, its communication performance has been tested in laboratory. Finally, different tests have been carried out in two MV smart grid real installations under normal operation, i.e., in the presence of the mains voltage

A new PLC-based smart metering architecture for medium/low voltage grids: Feasibility and experimental characterization

This paper investigates the feasibility of a smart metering architecture for modern power grids in the smart cities framework. A particular focus is made on Automatic Meter Reading, with the aim of facing some costs and safety drawbacks of current solutions (such as dependence from wireless communication providers, reliability problems in bad weather conditions, and exposition to cyber-attacks). The proposed architecture exploits power line communications (PLC) at both low and medium voltage level, thanks to new devices and an innovative medium voltage PLC coupling system. The new coupling solution and the whole smart metering architecture are experimentally verified in a wide frequency range, from CENELEC A band up to 200 kHz, by using different modulation techniques; the on-field measurement campaign has been carried out on the distribution network of Favignana Island (Mediterranean Sea). Success rate and RTT measured in real environment confirm the feasibility of the proposed solution

An innovative power line communication solution for medium voltage smart grids applications

This paper summarizes the authors research activity concerning the design, modeling and experimental characterization of a new coupling system for medium voltage (MV) narrow band power line communications (NB-PLC). The proposed solution has been patented by authors and it exploits the capacitive divider of voltage detecting systems (VDSs) normally used to reveal the mains voltage presence, thus avoiding the use of dedicated MV couplers. In the following, the modeling of the VDS capacitive divider is presented and the interface card design is described, based on simulation of the whole PLC transmission channel. Laboratory tests are also presented. Finally, the results are shown of an on-field measurement campaign, which has been carried out the MV distribution networks of the Islands of Ustica and Favignana. Transmission tests demonstrate that the proposed VDS coupling system can be effective for narrowband modulated signal transmission

UNCERTAINTY ANALYSIS OF POWER RATIO PARAMETERS FOR HARMONIC EMISSION ASSESSMENT IN POWER SYSTEMS

To promote regulation strategies and incentives for harmonic mitigation, simple tools are needed for evaluating harmonic pollution levels at point of common coupling (PCC), as well as on the whole grid. Starting from IEEE Std. 1459-2010 approach [1] and the common concept of power factor correction, in [2] the authors have presented a preliminary study, aimed at investigating the possibility of using power ratio parameters for harmonic emission assessment. Being the formulation of IEEE Std. 1459 power quantities and related power ratio indicators very simple, the proposed indicators measurement can be easily integrated in common measurement instruments, thus allowing easily the assessment of harmonic emissions and related billing/incentives strategies implementation. In this context, it is important to investigate the measurement uncertainty impact on the evaluation of considered power ratios (both those defined in IEEE Std. 1459 and the new proposed ones) [2]. To this aim, the measurement of the considered parameters has been implemented on a PC-based sampling wattmeter. Starting from the instrumentation accuracies and the correlation analysis, combined standard uncertainties of power ratio indicators have been evaluated and a comparison has been made between IEEE Std. 1459 indicators and the newly proposed ones