Power Quality Evaluation of a Photovoltaic System on an Electric Grid

This paper focuses on tests of photovoltaic systems in order to address two case studies with silicon monocrystalline and silicon polycrystalline panels, respectively. The first case is an identification of the three parameters of the single-diode equivalent circuit for modelling photovoltaic systems with conclusion about the inevitably age degradation. A comparison between experimental observed and computed I-V and V-P characteristics curves is carried out at standard test conditions. The second case is an experimental observation on a photovoltaic system connected to an electric grid in what regards the quality of the energy injected into the grid. A measuring of the harmonic content in the voltage and in the current waveforms at the terminals of the photovoltaic system is carried out in order to conclude about the conformity with the Standard EN 50160 and the IEEE 519-1992, respectively.

Vanadium Redox Flow Battery Storage System Linked to the Electric Grid

This paper focuses on technology state of the art for the charge/discharge of electric energy storage supported by vanadium redox flow battery linked to the electric grid. Properties of vanadium, the main configuration and the reaction of charge/discharge of a vanadium redox flow battery are addressed. The vanadium redox flow battery has the highest cell voltage among the other redox flow battery, implying higher power and energy density which favours application at power plants. This electric energy storage is viewed as a promising contribution to be integrated in power system due to a reasonably bulky size and to successful applications currently allowing storage of energy at power plants or at electrical grids. For instances, allowing storage of energy as an economic improvement providing spin reserve to avoid penalty for imbalances between the energy delivered and energy contracted at closing of electricity market or as an economic improvement to diminish the cost of electricity usage of a consumer. The vanadium redox flow battery has the advantages of scalability customized to meet requirements for power and energy capacity and of excellent combination of energy efficiency, capital cost and life cycle costs compared with other technology.

Offshore Wind Energy Conversion System Connected to the Electric Grid: Modeling and Simulation

This paper is on modeling and simulation for an offshore wind system equipped with a semi-submersible floating platform, a wind turbine, a permanent magnet synchronous generator, a multiple point clamped four level or five level full-power converter, a submarine cable and a second order filter. The drive train is modeled by three mass model considering the resistant stiffness torque, structure and tower in deep water due to the moving surface elevation. The system control uses PWM by space vector modulation associated with sliding mode and proportional integral controllers. The electric energy is injected into the electric grid either by an alternated current link or by a direct current link. The model is intend to be a useful tool for unveil the behavior and performance of the offshore wind system, especially for the multiple point clamped full-power converter, under normal operation or under malfunctions.