Search results for "power system"
showing 10 items of 322 documents
Current transformers effects on the measurement of harmonic active power in LV and MV networks
2011
The harmonic active power is used to determine the location of polluting loads, the direction of harmonic power flow and to estimate how consequential a certain current harmonic source is. The highest uncertainties, when measuring harmonic active power, are introduced by the current and voltage transducers. This paper presents experimental results which show the impact of current transformers (CTs) on the accuracy of the harmonic power measurements. An expression for the evaluation of the power error in distorted conditions was developed which can be easily utilized in the case of linear current transducers. It is shown how CTs cannot be considered linear transducers and how the higher the …
Energy and economic assessment of a small domestic wind turbine in Palermo
2016
The cost effectiveness of micro-wind technology is closely linked to the annual energy production plants, which strongly depends on the wind characteristics and on the morphological properties of the installation site. The power curve of a wind turbine, supplied by manufacturers, characterizes the theoretical energy performance that it should have at a particular site. The behavior of a wind turbine in the field is affected by the speed but also by wind direction variations. At each change of direction and speed, the turbine will try to adapt to new conditions and the phase transition negatively influences the energy production. In order to experimentally confirm what above mentioned, the a…
A Dynamic Electrical Scheme for the optimal reconfiguration of PV modules under non-homogeneous solar irradiation
2012
This paper presents a strategy for the maximization of the output power of photovoltaic (PV) systems under non homogeneous solar irradiation by means of automatic reconfiguration of the PV arrays layout. The innovation of the proposed approach is the employment of a simple Dynamic Electrical Scheme (DES), allowing a large number of possible modules interconnection, to be installed between the PV generator and the inverter. The models of the PV generator and of the DES have been realized and simulated with Simulink (Dynamic System Simulation for MATLAB). The attained experimental results appear to be quite interesting in terms of the attainable benefit in power and thus energy terms. The lim…
DEMAND Project: A Peak Load Shaving Strategy for End-User Consumers
2018
Battery energy storage systems (BESS) are becoming increasingly widespread in modern power systems, thanks to the important benefits they can provide to the electricity grid. Indeed, BESS can be used in time shifting applications, storing energy during off-peak periods and discharging during peak times (when the cost of electricity is high). When BESS are used for peak shaving purposes, they also contribute to relieve peak demand charges, thus ensuring a saving for the consumers. This paper describes a peak load shaving strategy defined within the DEMAND project. The strategy is able to guarantee the flattest daily power diagram and the maximum benefit for the electricity consumers, reducin…
An Innovative Coupling Solution for Power Line Communication in MV Electrical Networks
2019
One of the main problems in the diffusion of power line communication (PLC) in medium voltage (MV) networks is the need of a dedicated PLC coupler to be installed all over the network. To avoid this problem, the authors have studied, prototyped and patented an innovative PLC coupling solution which uses electrical elements embedded in most of the switchgears already installed in MV networks, i.e. the capacitive dividers of the voltage detecting systems (VDS). The new solution prototype is described in this paper, highlighting the advantages in terms of a significant reduction of both direct costs of equipment and infrastructures and indirect costs of installation and service interruption. T…
Model of line to shield power line communication system on a Medium Voltage network
2010
In this paper a complete model of a power line communication (PLC) system on a Medium Voltage (MV) network is presented in the case of a line-ground configuration. A simple and friendly Simulink (R) software is used to develop the model. A distributed parameter MV cable model in line-ground configuration is considered together with the power transformers, the signal coupling networks and the receiving and transmitting line coupling interface of a ST7540 FSK powerline transceiver. The performances of the complete PLC communication system are evaluated for different line lengths by means of the attenuation computed as ratio between the received and transmitted voltage signals.
Power Line Communication in Medium Voltage Systems: Characterization of MV Cables
2008
The aim of this paper is to illustrate the development of a theoretical and experimental study on the characterization of medium voltage (MV) cables in the frequency range 25-200 kHz. Two transmission line configurations, line-ground and line-line, were considered in order to evaluate the main parameters, such as the characteristic impedance and the attenuation constant alpha. A simplified model of the line-ground configuration is proposed which allows one to evaluate the characteristic impedance and the attenuation constant by means of geometrical dimensions. The model was verified by experimental measurements on commonly used MV cables, RG7H1R, with an aluminium core of different sections…
Simulation of a Power Line Communication System in Medium and Low Voltage Distribution Networks
2011
The aim of the paper is to study the influence of the power transformer on signal transmission in the case of a power line communication (PLC) system in a overhead Medium Voltage (MV) power network. A model of the PLC system was carried out by means of the Simulink® software. A distributed parameter MV overhead line, two power transformers, the signal coupling networks and the receiving and transmitting line coupling interface of a ST7540 FSK powerline transceiver were included in the model. The performances of the complete PLC communication system are evaluated for different line lengths by means of the attenuation computed as ratio between the received and transmitted voltage signals.
Measurement and communication interfaces for distributed generation in smart grids
2013
The aim of this work is to perform a feasibility study on the measurement and communication strategies for the development of a new generation of interface devices for distributed generators and their integration on smart grids. The communication system can use one or more technologies, at the various levels, creating a low cost network infrastructure, in the framework of a SCADA (Supervisory Control and Data Acquisition) architecture. As regards the measurements, the attention is focused on the anti-islanding protection, based on a hybrid solution, which makes use of local measurements and communications with the grid, at both MV and LV level by employing the PLC technology. Some simulatio…
An interface protection system with power line communication for distributed generators remote control
2014
The aim of this work is to present a narrow band power line communication (NB-PLC) interface protection system (IPS) for distributed generators (DGs); it has been developed according to the current standard CEI 0-21 and the requirements for smart grid applications. For such applications, the new IPSs have to implement new intelligent functions such as remote monitoring and control of DGs and Energy Storage Systems (ESSs) inverters, not only in terms of disconnection but also of voltage regulation and power modulation by the utility control. The main feature of the developed IPS is the ability to interact with both the grid and the DG's and ESS's inverters. In fact, it can communicate with t…