João Tavares Pinho

Influence of the discharge pulse width in the current distribution on OPGW cables

The objective of this paper is to show the influence of the duration of a lightning pulse on OPGW cables, using the BOR-FDTD method and analyzing the current density distribution along the radial direction for different pulse widths.

Influência mútua entre harmônicos e cargas não-lineares

This work presents and analyzes cases where mutual influence between voltage and/or current harmonic content and nonlinear loads occurs. These influences are exemplified by means of undertaken measurements and simulations, such as: the supply of nonlinear loads with different voltage waveforms, especially loads composed of a rectifier with capacitive filter; the influence of current harmonic content in the supply voltage; the combination of three-phase and single phase loads; and the mutual influence of harmonic content of shunt-connected loads, emphasizing, in these last two cases, the possibility of harmonic compensation.

Implementation and Validation of Energy Conversion Efficiency Inverter Models for Small PV Systems in the North of Brazil

The increasing amount of distributed photovoltaic (PV) system components into distribution networks involves the development of accurate simulation models that take into account an increasing number of factors that influence the output power from the distributed generation systems. The modeling of PV system components in power systems and the relative control architecture is an important part of the introduction of a relevant quantity of renewable energy to the future development of the smart grid. Therefore, it is essential to have proper validated models to help operators perform improved studies and be more confident with the results. We present two energy conversion efficiency inverter models developed for two small PV systems using the Jantsch inverter models (Jantsch, Schmidt, Schmid, Results of the concerted actions on power conditioning and control. XI European Photovoltaic Solar Energy Conference, Swiss, 1992) and Sandia inverter model (King, Gonzalez, Galbraith, Boyson,Performance model for grid-connected photovoltaic inverters, Sandia National Laboratory Report, New Mexico, 2007). The component models were implemented in MATLAB software and the simulation results were compared, firstly, with the datasheet values of the inverter Xantrex GT2.8-NA-240/208 UL-05 model and then with the microinverter Enphase® Energy (M215) model. To confirm the strong dependency on ambient conditions and to validate the simulation models, operation data from two small PV systems using the Xantrex and Enphase Energy inverters located in the north of Brazil were used and statistical analysis and comparison of the results was performed.

Regulatory Actions due to Small Termal Plants of Isolated Systems Using Telemetering Control

In Brazil, the small isolated electrical systems are able to attend just 2% of the total electricity market of Brazil, although an amount of 340 thermal plants are spread along 40% of its territory. One of the main problems of these systems is the lack off supervisory control, related to the distances involved and telecommunication difficulties. On the other hand, these plant owners receive oil with subsidized price that is paid by the total electricity market agents of the country. The total subsidy account was about US

Analysis of current density distributions over the cross-section of OPGW cables using an analytical model and the FEM numerical method

1.5 billion in 2004. This paper show an application of telemetering in four small power plants of Amazon Region, performed by ANEEL (Brazilian Electricity Regulatory Agency) associated with ARCON (State of Paraacute Regulatory Agency), in order to establish some kind control for these systems. The least cost of these project related to the traditional supervisory and control systems is the system greater attractive. The data collected is treated and the results have been signalizing a plenty of corrective actions, like as changes in the dispatch scale, improving operative conditions with a best economic response. The results were very expressive, so we can highlight the ANEEL Regulatory Act 163/2005, that provides issues to install similar control systems in the power plants all over the isolated systems of Brazil.

Methodology of risk analysis by Monte Carlo Method applied to power generation with renewable energy

Multiconductor OPGW cables have a double function: they serve for lightning protection and as a communications channel. In this work, we present some results of the analysis of current density distributions in these cables obtained by an analytical method and using the FEMLAB software.