Search results for "VOLTAGE"
showing 10 items of 934 documents
Mitigation of 50 Hz magnetic field produced by an overhead transmission line
2015
Power transmission utilities are challenged by the need to expand transmission system capacity to meet growing energy demands. The impact of high voltage overhead transmission lines on the environment represents a hot topic in the context of transport and distribution of electrical energy. In particular, interest towards the effects of extra low frequency (ELF) magnetic fields generated by high-voltage power transmission lines has been increasing significantly during the last decade, giving rise to a number of policy initiatives and research activities. Therefore, the evaluation of the magnetic field generated by conductors of overhead lines is of primary importance in order to develop meth…
Comparative evaluation of pulse width modulation techniques on effective DC link voltage utilization of grid connected inverter
2016
In this paper, comparison between two different Pulse Width Modulation (PWM) techniques employed for three phase voltage source inverter (VSI) is discussed. The three phase voltage source inverter is basic topology used to supply a grid. In this paper we have design a LC filter between the inverter and the grid in order to stabilize the output voltage. The filter gives sinusoidal three phase voltage at the output of the inverter with almost zero/less harmonic distortion. A suitable PWM technique is employed to obtain the required output voltage in the line side of the inverter. The PWM generation techniques used mainly based on sinusoidal based Pulse Width Modulation (SPWM) and Space Vector…
Numerical investigation of the induced voltage on a cable placed at random locations inside a metallic enclosure
2008
In this paper, we investigate the induced voltage on a cable when placed at random locations inside a metallic enclosure. The analysis consists of a cable of defined length and fixed terminals, but different layouts, placed in a metallic enclosure containing an aperture. The induced voltages for the different layouts are computed for a plane wave incident on the aperture. A second analysis is performed with no cable (i.e., an empty enclosure) and the results are compared to those for the cable present. The results are compared to the resonance frequencies of the closed cavity and the aperture.
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…
Steady-state security analysis on the transmission grid for various scenarios of wind generation in Sicily
2009
The proposed paper is part of a research aimed at assessing the impact of wind generation on the transmission grid of Sicily, second among the Italian regions for wind power installed. After describing the current state of wind energy generation in Sicily, the paper reports and comments the results of the steady-state security analysis done for various scenarios of wind penetration. For each scenario (maximum and minimum load conditions), the redistribution of power flows on the transmission network, the voltage profiles at nodes, the analysis of contingencies and losses variations are reported.
A device for PV modules I-V characteristic detection
2013
In this paper an electronic load suitable for the PV module I-V characteristic curve fast detection is presented. This device is designed in agreement with the IEC 82 Techinical Committee Standard since it allows the detection of the characteristic starting from voltage values even lower than 3% of the PV module open circuit voltage. The device main features are short time characteristc detection (2 s), limited ripple of the detected characteristic and low cost. Its validation is carried out by comparing measured data with data from simulations. Simulations are carried out considering two different commercial PV modules and by implementing in Matlab-Simulink environment the four lumped para…
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…
Non-linear digital control improving transient response: Design and test on a multiphase VRM
2010
Multiphase interleaved buck converters are widely used for point of load applications, especially for VRMs. Performance optimization issue often clashes with size and cost requirements thus leading the industrial and academic research to focus on advanced solutions. This paper presents a control technique for multiphase VRMs including two interacting sections: the linear loop implements a PWM peak current mode control and the nonlinear subsystem modifies few linear loop parameters under load transients only. Steady-state performances are affected by the linear control only while dynamic performance optimization is a non-linear algorithm issue. The proposed control system improves the dynami…
Design issues for wind farms grid tied Inverter
2017
In this paper the Authors give indications for the design of a grid tied Voltage Source Inverters (VSI) aimed to optimal use in energy conversion from wind source. In particular, the design of the inverter is more focused on the control system planning, with a particular glance on the grid synchronization problem. After the exposition of general issues concerning renewable energies and associated topics, the case of a grid tied inverter is considered and a methodology of design is sketched starting from the consideration of the DC side and also considering the power device losses, the protection issue against over voltages and over-currents, snubber circuits, heat sinks and, finally the con…
Medium Voltage Smart Grid: Experimental Analysis of Secondary Substation Narrow Band Power Line Communication
2013
This paper is focused on the possibility of employing narrow band power line communication (PLC) in medium voltage (MV) distribution networks. The topic is investigated by means of both simulations and experimental tests, which were carried out in the distribution network of Ustica Island. In detail, a two-way MV communication was tested between two secondary substations connected by an MV cable power line. Each substation has a by-pass connection at MV bus-bars and an MV/LV oil filled power transformer. In this paper, the MV and the PLC systems under test are described and the experimental tests are presented, which were carried out to evaluate the parameters of the simulation model. The a…