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Photocatalytic mechanism of V2O5–TiO2 nanocomposites with a leaf like morphology synthesized for the first time by mechanical alloying.

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<span lang="EN-US">When severe voltage sags occur in weak power systems associated with grid-connected wind farms employing doubly fed induction generators, voltage instability occurs which may lead to forced disconnection of wind turbine. Shunt flexible AC transmission system devices like static synchronous compensator (STATCOM) may be harnessed to provide voltage support by dynamic injection of reactive power. In this work, the STATCOM provided voltage compensation at the point of common coupling in five test cases, namely, simultaneous occurrence of step change (drop) in wind speed and dip in grid voltage, single line to ground, line to line, double line to ground faults and sudden increment in load by more than a thousand times. Three techniques were employed to control the STATCOM, namely, fuzzy logic, particle swarm optimization and a combination of both. A performance comparison was made among the three soft computing techniques used to control the STATCOM on the basis of the amount of voltage compensation offered at the point of common coupling. The simulations were done with the help of SimPowerSystems available with MATLAB / SIMULINK and the results validated that the STATCOM controlled by all the three techniques offered voltage compensation in all the cases considered.</span>

Multi-level inverters (MLIs) with switched capacitors are becoming popular due to their utilization in AC high-voltage applications as well as in the field of renewable energy. To achieve the required magnitude of output voltage, the switched capacitor (SC) technique employs a lesser number of DC sources in accordance with the voltage across the capacitor. Designing an efficient high-gain MLI with fewer sources and switches needs a rigorous effort. This paper introduces a prototype of a nine-level quadruple boost inverter (NQBI) topology powered by one solar photo-voltaic source using fewer capacitors, switches, and diodes when compared to the other SC-MLIs topology. The suggested NQB inverter produces nine levels of voltage in its output by efficiently balancing the voltages of the two capacitors. The various SC-MLIs are compared in order to highlight the benefits and drawbacks of the proposed nine-level quadruple boost inverter (NQBI) topology. To validate the efficacy of the proposed solar photovoltaic based NQBI without grid connection, detailed experimental results are presented in a laboratory setting under various test conditions.

The microgrid (MG) networks require adaptive and rapid fault classification mechanisms due to their insufficient kinetic energy reserve and dynamic response of power electronic converters of distributed generation (DG) systems. To achieve this requirement, this study explores the issues in standalone (SA) and grid-connected (GC) operating modes of MG and develops a near-real-time intelligent disturbance detection and protective solutions for their stable operation. In the proposed approach, an intelligent fault classification mechanism is developed using the advantages of wavelet transform and convolutional neural networks (CNNs). Initially, the voltage and current outcomes for each and every possible fault in the MG network are identified and the wavelet transforms are applied for preprocessing and image conversion. The converted images are identified as scalograms which are further trained with the CNNs. To assess the development of the proposed approach, the IEEE 13 bus system is considered for data gathering. To replicate the real-time behavior of the MG network, the additive white Gaussian noise (AWGN) and additive impulsive Gaussian noise (AIGN) are injected at various levels during the classifier development process. The trained classifier has an average training accuracy of 99.1% for SA MG and 97.7% for GC MG, and the average testing accuracies are 98.9% for SA MG and 97.1% for GC MG.

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