Search results for "Low voltage"
showing 10 items of 49 documents
A Method to Evaluate Voltages to Earth During an Earth Fault in an HV Network in a System of Interconnected Earth Electrodes of MV/LV Substations
2008
An easy and swift method to evaluate, in a system of interconnected earth electrodes, earth potentials on earthing systems of medium-voltage/low-voltage (MV/LV) substations, in an event of single-line-to-earth fault inside a high-voltage/medium- voltage (HV/MV) station, is presented. The advantage of the method is the simplicity of the mathematical model for solving complex systems of any size with a sufficient accuracy for practical purposes. This paper shows the results of simulations, performed on networks with different extensions and characteristics, organized in easy-to-read graphs and tables. A comparison of these results with the values obtained according to the procedure explained …
New Measurement Procedure for Load Flow Evaluation in Medium Voltage Smart Grids
2013
The aim of this paper is to present a new approach for the medium voltage (MV) distribution network load flow analysis, mainly based on power measurement at the low voltage (LV) level of MV/LV distribution substations. This allows to use measurement instruments, usually already installed in the secondary substations, thus achieving an equally reliable measurement system with a lower cost compared to measurements at the MV side. The new approach can be applied using a proper communication system to collect the nodal measurements and an iterative algorithm based on ladder iterative technique (LIT) to compute the load flow. The validity of this method is presented and discussed on the basis of…
On the use of narrow band power line as communication technology for medium and low voltage smart grids
2012
The aim of this work is to perform a feasibility study on the power line communication for the development of a new generation of interface devices (IDs) for smart grid applications. More in detail, this paper deals with one of the most important issues on this topic which is the communication system. Among the existing communication technologies, the study is focused on power line communications (PLCs). After a analysis of the state of the art in the field, the main aspects are analyzed, concerning the open issues on the use of PLCs, especially for medium voltage (MV) and low voltage (LV) systems. In this work the use of PLC in MV-LV networks is investigated, by means of simulations and ex…
Development details and performance assessment of a Wind Turbine Emulator
2016
This paper describes an experimental platform to emulate the static and dynamic behavior of real Wind Energy Conversion Systems (WECS). The Wind Turbine Emulator (WTE) consists of two coupled 1.5 kW squirrel-cage induction machines. The WTE calculations are performed on a PC and a DSP, both connected via USB. The total torque applied to the WTE motor is the difference of the scaled wind mechanical torque calculated on the PC, and the turbine inertia torque calculated on the DSP. An improved WTE shaft speed derivative has been used for the inertia torque calculation, which provides better results in terms of attenuation of the high-frequency harmonics present in the generator speed acquisiti…
Experimental evaluation of an hybrid communication system architecture for smart grid applications
2015
In this paper a new communication system architecture is proposed for the development of a SCADA system which can remotely monitor and control intelligent electronic devices (IEDs) connected to the low voltage distribution networks, i.e low voltage smart meter (SM), interface protection devises (IPS). New distributed metering systems and interface devices, together with a proper communication infrastructure (HiperLAN and narrowband power line communication (NB-PLC) on low voltage network), have been developed to allow monitoring the whole power system and controlling the distributed generators of a Smart Grid also in the presence of harmonic distortions. In this way, the electrical energy d…
Probabilistic Approach to the Design of Photovoltaic Distributed Generation in Low Voltage Feeder
2006
This paper presents the probabilistic approach to the design of photovoltaic (PV) distributed generation (DG) and its impact on low voltage (LV) feeder. Monte Carlo simulation is used to predict solar radiation and load, and an exact method is used to solve the power flow. The method is tested on two study cases, and the results are compared with those from deterministic approach based on commonly used scenarios. The probabilistic approach is shown necessary to obtain the optimum PV rating based on technical constraints and different objectives, including accepting a reasonable risk when needed. The results also indicate that PV-DG in a realistic case will most probably improve the voltage …
A comparison of two innovative customer power devices for Smart Micro-Grids
2015
The paper presents a comparison of two prototypes of innovative Customer Power Devices designed for applications in Smart Micro-Grids. The devices are both equipped with Energy Storage Systems, consisting in Lithium batteries and have been assembled, independently, by the DIAEE of the University of Rome 'La Sapienza' and the DEIM of the University of Palermo in collaboration with the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). In the paper, the characteristics and the operating modes of the devices are examined and some consideration on their application in Low Voltage Smart Micro-Grids are provided. © 2015 IEEE.
A bidirectional converter for the integration of LiFePO4 batteries with RES-based generators. Part II: Laboratory and field tests
2014
This paper presents a device for controlling and connecting combined Renewable Energy Sources (RES)-based generators and electric storage systems to the supply utility grid. The device is a bidirectional converter that can be controlled in order to facilitate the interface between the low voltage grid and small generators combined with Li-ion batteries, contemporary addressing the requirements of the reference technical standards for users connection and providing different ancillary services. The paper describes the laboratory and field test activities carried out by the DEIM of the University of Palermo and ENEA during 2013.
Uncertainty evaluation of a Backward/Forward Load Flow algorithm for a MV smart grid
2015
This paper presents the uncertainty evaluation of an innovative measurement algorithm for load flow analysis in MV distribution networks. The measurement procedure is based on Low Voltage (LV) load power measurements applied on a Backward/Forward (B/F) algorithm for the Load Flow (LF) resolution. Furthermore, in the procedure a three phase voltage measurement at the MV generating substation bus-bars is also considered. The accuracy analysis of the LF algorithm is performed in the case of a real load condition in the distribution grid of Ustica island, Italy. The analysis takes into account the uncertainty of the measurement instruments at the LV side of each secondary substation power trans…
Experimental study of low-voltage surge protection device response in realistic systems
2008
Experimental results on low-voltage surge protection under fast pulses in realistic wiring systems are presented. A fast voltage pulse generator is designed to provide fast voltage pulses with short steep fronts. The effective residual voltage of protected equipment is then investigated and compared with simulation results.