Search results for "Volt"

Verifying the effect of distributed generators on voltage profile, power losses and protection system in radial distribution networks

2013

In the recent years the electrical power networks are undergoing rapid restructuring and developing process worldwide. Advancement in technologies and concern about the environmental impacts have led to increase interconnection of renewable energy based distributed generations (DGs) in distribution networks. The DGs have significant impacts on the distribution systems; these impacts may be either positively or negatively depending on the modified interconnected DG distribution network structure. It will be necessary to consider many issues concerning these impacts. In this paper, an investigation of DGs impacts on voltage profile, power losses, and protection system in radial distribution n…

Real-Time Minimization Power Losses by Driven Primary Regulation in Islanded Microgrids

2020

Islanded microgrids are small networks that work independently from the main grid. The frequency and voltage in islanded microgrids are affected directly by the output power of distributed generators and power demand variations. In this work, a real-time driven primary regulation, which relies on optimized P-f droop coefficients, is proposed. In all operating conditions, it minimizes the power losses for islanded microgrids. The proposed configuration will allow the optimization modules to interact with each other and adjust parameters producing a suitable power sharing among generators. The methodology is tested based on a hardware-in-the-loop experimental set-up where distributed generato…

Transient stability simulation of a fixed speed wind turbine by Matlab/Simulink

2007

This paper describes the dynamic behavior of a typical fixed speed wind turbine connected to the grid; the model is developed in the simulation tool Matlab/Simulink and created as a modular structure. The pitch control system is used for stabilization of the wind turbine at grid faults. In this way, voltage stability of the system with grid-connected wind turbines can be improved by using blade-angle control for a temporary reduction of the wind turbine power during a short-circuit fault in the grid. This paper shows a new variable control for maintaining of voltage stability, when a three-phase fault is applied close to the wind turbine and cleared by disconnecting the affected line. In th…

Considering safety issues in minimum losses reconfiguration for MV distribution networks

2009

This paper offers a new perspective over the traditional problem of the multiobjective optimal reconfiguration of electrical distribution systems in regular working state. The issue is indeed here formulated including also safety issues. Indeed, dimensioning the earth electrodes of their own secondary substations, distribution companies take into account the probable future configurations of the network due to transformations of overhead lines into cable lines or realization of new lines. On the contrary, they do not consider that, during normal working conditions. the structure of the network can be modified for long periods as a consequence of reconfiguration manoeuvres, with differences …

Quantitation of Metal Ions in Archaeological Glass by Abrasive Stripping Square-Wave Voltammetry Using Graphite/Polyester Composite Electrodes

2003

A method for identifying Co, Cu, Sb, Sn, Fe, Zn, and Zr pigments in glasses using square-wave voltammetry as the detection mode is described. It is based on the abrasive attachment of glass microsamples to graphite/polyester composite electrodes. Sample amounts less than 1 μg are used allowing for the study of archaeological samples. In all cases well-defined anodic stripping peaks corresponding to the oxidation of metal deposits generated at potentials ranging from −0.6 to −1.6 V (vs. SCE) are obtained. This response is in agreement with that displayed by the corresponding metal oxides. Quantitative estimates of the relative population of metal ions in glasses are obtained from peak area m…

Synthesis of phosphine derivatives of [Fe2(CO)6(μ-sdt)] (sdt = SCH2SCH2S) and investigation of their proton reduction capabilities

2023

The reactions of [Fe2(CO)6(μ-sdt)] (1) (sdt = SCH2SCH2S) with phosphine ligands have been investigated. Treatment of 1 with dppm (bis(diphenylphosphino)methane) or dcpm (bis(dicyclohexylphosphino)methane) affords the diphosphine-bridged products [Fe2(CO)4(μ-sdt)(μ-dppm)] (2) and [Fe2(CO)4(μ-sdt)(μ-dcpm)] (3), respectively. The complex [Fe2(CO)4(μ-sdt)(κ2-dppv)] (4) with a chelating diphosphine was obtained by reacting 1 with dppv (cis-1,2-bis(diphenylphosphino)ethene). Reaction of 1 with dppe (1,2-bis(diphenylphosphino)ethane) produces [{Fe2(CO)4(μ-sdt)}2(μ-κ1-dppe)] (5) in which the diphosphine forms an intermolecular bridge between two diiron cluster fragments. Three products were obtaine…

Fotovoltaico negli edifici

2009

Energie rinnovabili: Rapporti diretti e indiretti e strumenti di tutela

2012

Sustainable greenhouse horticulture in Europe

2012

Technical and economic aspects of photovoltaic conversion of southern Poland

2014

W artykule przedstawiono wyniki 13-letniej analizy testowania sprawności oraz uzysku energii i ładunku elektrycznego typowych modułów fotowoltaicznych wykonanych z różnych absorberów, zainstalowanych na południowej ścianie budynku Uniwersytetu Opolskiego przy ulicy kard. B. Kominka. Zarejestrowane w tym okresie (2001-2013) wartości kumulacji energii i ładunku testowanych modułów przedstawiono zarówno w odniesieniu do 1 Wp ich mocy nominalnej, jak i do 1 m2 powierzchni modułów PV. Przedstawiono ich roczne i miesięczne rozkłady ze szczególnym uwzględnieniem sezonowości zmian ich parametrów oraz zjawiska starzenia i degradacji struktury modułów PV. W końcowej części artykułu zaprezentowano eko…