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This research work proposes a planning strategy pertaining to the techno-economic operation of Indian power systems. The proposed strategy focused on the reactive power (VAr) planning (RPP) subject to the system operating cost minimization ensuring system security. To mitigate the RPP issue, unique meta-heuristic hybridized techniques are adopted to size the optimal parameter settings such as alternator's reactive power, tap settings of transformers etc. instigated by power flow analysis satisfying all equality and inequality constraints. The controlling variables are optimally determined to solve this non-linear RPP problem. The bottleneck for the installation of static VAr compensators at weak buses is also wiped out by different analytical techniques viz. loss sensitivity, power flow and modal analysis. Two different inter-regional transmission networks prevailing in India are considered to measure the adaptability, efficacy and efficiency of the proposed approach. The results obtained by applying the proposed approach have confirmed that network loss-minimization procedures produce an acceptable solution and reduce the operating cost which is especially important in RPP. The responses of bench mark functions and statistical analysis of the outcomes from both systems allow us to assess the overall efficiency and efficacy of the proposed techno-economic planning approach. [ABSTRACT FROM AUTHOR]

This study introduces a techno-economic planning strategy of reactive power (VAr) in power transmission systems. This planning strategy primarily has been focused on reactive power planning (RPP) through operating cost minimisation ensuring cost-oriented system security. The objective function (operating cost) is blended with four different components viz. cost due to real power loss, VAr generation cost, additional VAr compensation devices cost and line charging cost. FACTS (flexible AC transmission system) devices are installed at weak positions through different echelons to improve the system voltage stability. The authors also implemented the probabilistic hybridisation of crow search algorithm and JAYA to find out the optimal set of controlling parameters related to VAr. Finally, a sharp and minute analysis of the results has been done to validate the proposed strategy under multi-loading conditions. To understand the efficiency and efficacy the code profiling and simulation has been rendered on IEEE 30 bus and UPSEB 75 bus test system. [ABSTRACT FROM AUTHOR]

This study introduces a techno‐economic planning strategy of reactive power (VAr) in power transmission systems. This planning strategy primarily has been focused on reactive power planning (RPP) through operating cost minimisation ensuring cost‐oriented system security. The objective function (operating cost) is blended with four different components viz. cost due to real power loss, VAr generation cost, additional VAr compensation devices cost and line charging cost. FACTS (flexible AC transmission system) devices are installed at weak positions through different echelons to improve the system voltage stability. The authors also implemented the probabilistic hybridisation of crow search algorithm and JAYA to find out the optimal set of controlling parameters related to VAr. Finally, a sharp and minute analysis of the results has been done to validate the proposed strategy under multi‐loading conditions. To understand the efficiency and efficacy the code profiling and simulation has been rendered on IEEE 30 bus and UPSEB 75 bus test system. [ABSTRACT FROM AUTHOR]

In a competitive electricity power market, reactive power planning (RPP) is a pivotal matter for the power system researchers from operational and economical view points. RPP is concerned with the installation or removal of reactive power equipment in power system. This article proposes an effective way to find out the optimal parameter settings related to the system active power loss as well as operational cost. Genetic Algorithm (GA)-based strategy is applied to determine the optimal values of reactive power generation of generators, size of shunt capacitors, transformer tap settings prior to minimizing the system operating cost due to active power loss, installation cost of shunt capacitors at the weak nodes, and the cost of line-charging elements. The proposed approach is applied to IEEE 30 and IEEE 57 bus test system. Finally, a comparative analysis has been done to validate the efficacy of GA-based approach with some well-established meta-heuristic algorithms. [ABSTRACT FROM AUTHOR]

This paper aims to percolate energy management of microgrid systems by minimizing the generation cost of the same. Energy management of microgrid refers to the optimal sizing and scheduling of the distributed energy resources to reduce the generation cost and pollutant emission. A recently developed crow search algorithm (CSA) is implemented to execute the optimization. The proposed CSA imitates the crows' memory and tactics of hiding and chasing their food. Six renewable integrated microgrid test systems and a total of eighteen different cases are considered for this study. Various practical complexities such as valve point loading effect, combined economic–emission dispatch using price penalty factor method, modeling of the renewable energy sources and energy storage systems are taken into consideration for energy management of the microgrid systems. Results obtained are then compared to a number of different soft computing techniques such as genetic algorithm and particle swarm optimization and the likes to justify the effectiveness of the proposed algorithm. A statistical analysis, viz. Wilcoxon signed-rank test, is performed to prove the superiority of the proposed approach over the various other optimization techniques used in the paper. [ABSTRACT FROM AUTHOR]

• Consideration of the optimal phasor measurement unit placement problem without radial buses. • Phasor measurement unit is pre-assigned at each bus connected to radial bus. • A two-phase branch-and-bound algorithm is used to determine the strategic locations for placement of phasor measurement unit. • The redundancy measurement is performed for ranking the obtained multiples solutions. This paper proposes a mixed integer nonlinear programming (MINLP) formulation with binary-valued variables for the optimal installation of the phasor measurement units (PMUs) in a power network. The MINLP framework has been solved by a two-phase branch-and-bound algorithm (BBA) for the optimal PMU placement (OPP) problem. The present work deals with the solution of the OPP problem without considering the radial buses including in the optimal solution. PMU is pre-assigned to each bus connected to a radial bus such that the radial buses are excluded from the list of potential PMU locations. The programming technique is used to determine the optimum number of PMUs and their locations to make the interconnected power network completely observable. The proposed BBA may provide multiple solutions at the lowest objective value, each time the optimizer routine restarts. Therefore, the obtained optimal solutions are being ranked regarding the measurement redundancy index. The two-phase branch-and-bound algorithm is applied to IEEE standard test systems as well as to New England 39- bus and a northern regional power grid 246- bus system. The proposed algorithm has been compared with the existing programming techniques in the recent literature. The simulation results obtained by the proposed BBA indicate the effectiveness and the efficiency to detect the desired target. [ABSTRACT FROM AUTHOR]

Topological insulators are novel electronic materials, where time reversal symmetry protects the spin‐polarized surface states from backscattering. Although, the bulk offers a trivial semiconducting response to incident light, but the metallic surface states exhibit interesting electrical response towards the incident radiation, such as polarization dependent surface photocurrent and topological phase transitions. Here, we study the temperature dependent near‐infrared photoresponse in bismuth selenide (Bi2Se3) nano‐flakes. A very good photo‐sensitivity to near‐infrared 800 nm wavelength is observed for the temperature range 300–2 K. Voltage responsivity at 2 K (1.481 × 1010 VW−1) is estimated to be four‐order greater than at 300 K (2.095 × 106 VW−1) and is comparatively much higher than the previously reported values of voltage responsivity in other materials. Interestingly, we also find the temperature dependent existence of both positive and negative photoresponse in our device. An anomalous photoresponse reversal is observed at 2 K, where resistance of the nano‐flake increases under light illumination. We propose that this phenomenon is due to the topological surface states, which have dominant transport contribution at very low temperatures. These observations establish the fact that topological insulators can be further engineered to develop a dual state photo‐switch, by manipulating the bulk and surface state conduction contribution. [ABSTRACT FROM AUTHOR]

Summary: This article proposes a new meta‐heuristic optimization algorithm named grey wolf optimization algorithm based on leadership and hunting behavior of grey wolf for the reactive power planning of a connected power network. The performance of the proposed opposition‐based grey wolf optimization (OGWO) and grey wolf optimization (GWO) is examined and tested successfully in standard IEEE 14, IEEE 30, and IEEE 57 bus test systems for the minimization of active power loss and the total operating cost while maintaining voltage profile of the buses within permissible limit. Active power loss and total operating cost are minimized by optimal planning of the reactive generation of generators, transformer tap setting arrangements, and reactive output of shunt capacitors as installed at weak nodes under different loading conditions. The weak nodes are detected by power flow analysis. The results obtained by GWO algorithm is compared to other popular techniques recently reported in recent state‐of‐the‐art literature. It is observed that proposed OGWO and GWO algorithm yields much better result in terms of reducing operating cost and minimizing active power loss. Merit lies with GWO is that its simple structure for implementation and its ability not to be trapped in local minima, thus exploring wider search area. [ABSTRACT FROM AUTHOR]

Nanostructured materials exhibit broad spectral photodetection, strong light matter interaction and exotic optoelectronic properties compared to their bulk counterpart. To overcome the limitations of silicon based photodetectors, various nanomaterials have been investigated. Here we have used industrially viable stacked layer reactive sputtering method to grow rice-like nanostructured (rln) Cu 2 ZnSnS 4 (CZTS) thin films. The rln-CZTS film showed optical absorption coefficient one order of magnitude greater than the plain thin films of CZTS. Further, even under zero bias condition, broad spectral response (in visible and near infrared range) was observed. The rise and decay time constants for visible (532 nm) and near infrared (NIR) (1064 nm) light incident were 208 ms, 175 ms and 681 ms, 778 ms, respectively (for 1 mV bias). The improvement in photocurrent has been attributed to enhanced light harvesting due to the presence of nanostructures in thin film. Detectivity of 4.48 × 10 8 Jones over a large area was observed indicating that rln-CZTS would be a potential material for other technical applications. Deposition of nanostructured CZTS using industrially viable reactive sputtering with short anneal and fabrication of self-powered broadband photodetection device with low rise and decay time constants are the novelties of this work. [ABSTRACT FROM AUTHOR]

Phasor measurement unit (PMU) is a GPS-based monitoring equipment employed for the improvement of the stability and reliability of the electrical grid. In this work, an optimal PMU placement has been considered to utilize the least number of units in order to make the power network fully observable. Further, this article also suggests to not only determine the minimal number and optimal locations of PMUs but also installation of the maximum number of PMUs on the weakest bus in an electrical network. Thus, the weak bus based on line stability index utilizing load flow measurement is determined. Then a novel numerical methodology which depends upon binary integer linear programming, constrained by weak bus measurement is proposed in this paper. Also, the effect of a single PMU loss considering weak buses is shown. The developed approach has been conducted on standard IEEE -14, -118, -300 and New England 39-bus test systems. Finally, obtained results and comparison with different weak bus methodologies are shown and examined. [ABSTRACT FROM AUTHOR]

In the present work, reactive power planning problem along with voltage stability margin is addressed by effective co-ordination of reactive power sources. Modal analysis and L-index methods are used to detect weak nodes of the system accordingly. Differential Evolution (DE) and Genetic Algorithm (GA)-based optimization techniques are applied for the proper co-ordination of Var sources under base and increased loading conditions maintaining voltage stability of the connected power network. The problem is multi-objective and IEEE 30 bus system is taken as the standard system. It is observed that modal analysis based detection of weak nodes are more effective than the L-index-based detection. Moreover, the DE-based optimization algorithm gives better result compared to GA-based approach in maximizing reactive power reserves. [ABSTRACT FROM AUTHOR]

Microgrids (MG) can be considered as a reduced power system network wherein the generation, transmission, and distribution of power take place within a limited geographical area. They are employed to utilize the maximum penetration of renewable energy sources (RES). Microgrid also has advantages such as reduction of transmission losses and costs pertaining to such losses. In this research, economic dispatch, emission dispatch, combined economic emission dispatch (CEED) based on fractional programming (FP), and environment-constrained economic dispatch (ECED) were assessed. An MG system for three distinct scenarios is studied. A novel, robust, and powerful swarm-intelligence hybrid algorithm, created by amalgamating the features of the conventional gray-wolf optimizer (GWO), sine-cosine algorithm (SCA), and crow search algorithm (CSA), is implemented as the optimization tool for the study. A significant reduction in generation costs of about 4.50-9.75% was achieved throughout the study when the time-of-usage (TOU) electricity market pricing strategy was used instead of the fixed pricing strategy. Furthermore, the paper also dealt with the Demand Side Management (DSM) to facilitate the generation cost by managing the controllable load demand. The generation cost decreased by a notable amount when ECED was evaluated with a 15% and 20% DSM-based revised load curve for the MG system. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach for reactive power planning of a connected power network. Reactive power planning is nothing but the optimal usage of all reactive power sources i.e., transformer tap setting arrangements, reactive generations of generators and shunt VAR compensators installed at weak nodes. Shunt VAR compensator placement positions are determined by a FVSI (Fast Voltage Stability Index) method. Optimal setting of all reactive power reserves are determined by a GA (genetic algorithm) based optimization method. The effectiveness of the detection of the weak nodes by the FVSI method is validated by comparing the result with two other wellknown methods of weak node detection like Modal analysis and the L-index method. Finally, FVSI based allocation of VAR sources emerges as the most suitable method for reactive power planning. [ABSTRACT FROM AUTHOR]

Reactive power planning is one of the most challenging problem for efficient and source operation of an interconnected power network. It requires effective and optimum co-ordination of all the reactive power sources present in the network. Recently, Teaching Learning Based Optimization (TLBO) algorithm is evolved and finds its application in the field of engineering optimization. In the proposed work TLBO based optimization algorithm is used for reactive power planning and applied in IEEE 30 and IEEE 57 bus system. The results obtained by this method are compared with the results obtained by other optimization techniques like PSO (Particle swarm optimization), Krill heard, HSA (Harmony search algorithm) and BB-BC (Big Bang-Big Crunch). At the end, TLBO appears as the most effective method for reactive power planning among all the methods discussed and can be considered as one of the standard method for reactive power optimization. [ABSTRACT FROM AUTHOR]

This study presents gravitational search algorithm (GSA)-based optimisation technique for the optimum coordination of multi-type flexible AC transmission system (FACTS) devices with the existing reactive power sources present in a connected power network. Three types of FACTS devices: namely, unified power flow controller, static var compensator and thyristor controlled series capacitor are used in the present problem and IEEE-30 and IEEE-57 bus systems are taken as standard test systems. The existing reactive power sources are reactive generations of the generators and transformer tap setting arrangements. The main objective of the present study is to reduce active power loss, system operating cost including the cost of FACTS devices and congestion in transmission network. The result obtained with the proposed GSA-based approach is compared with the results obtained by genetic algorithm, differential evolution and particle swarm optimisation techniques. It is observed that by optimal placement of FACTS devices along with the optimal setting of the transformer tap arrangements and control of reactive generations of the generators line loss, system operating cost and transmission congestion is reduced significantly by the GSA-based method compared with other methods. [ABSTRACT FROM AUTHOR]

This study presents gravitational search algorithm (GSA)‐based optimisation technique for the optimum co‐ordination of multi‐type flexible AC transmission system (FACTS) devices with the existing reactive power sources present in a connected power network. Three types of FACTS devices: namely, unified power flow controller, static var compensator and thyristor controlled series capacitor are used in the present problem and IEEE‐30 and IEEE‐57 bus systems are taken as standard test systems. The existing reactive power sources are reactive generations of the generators and transformer tap setting arrangements. The main objective of the present study is to reduce active power loss, system operating cost including the cost of FACTS devices and congestion in transmission network. The result obtained with the proposed GSA‐based approach is compared with the results obtained by genetic algorithm, differential evolution and particle swarm optimisation techniques. It is observed that by optimal placement of FACTS devices along with the optimal setting of the transformer tap arrangements and control of reactive generations of the generators line loss, system operating cost and transmission congestion is reduced significantly by the GSA‐based method compared with other methods. [ABSTRACT FROM AUTHOR]

This paper presents binary particle swarm optimization (BPSO) technique for the optimal allocation of phasor measurement units (PMUs) for the entire observability of connected power network. Phasor measurement units are considered as one of the most important measuring devices in the prospect of connected power network. PMUs function may be incorporated to the wide-area connected power networks for monitoring and controlling purposes. The optimal PMU placement (OPP) problem provides reference to the assurance of the minimal number of PMUs and their analogous locations for observability of the entire connected power networks. Binary particle swarm optimization (BPSO) algorithm is developed for the solution of OPP problem. The efficacy and robustness of the proposed method has been tested on the IEEE 14-bus, IEEE 30-bus, New England 39-bus, IEEE 57-bus, IEEE 118-bus and Northern Regional Power Grid (NRPG) 246-bus test system. The results obtained by proposed approach are compared with other standard methods and it is observed that this BPSO based placement of phasor measurement units is found to be the best among all other techniques discussed. [ABSTRACT FROM AUTHOR]

In the proposed work, authors have applied swarm intelligence based algorithms for the effective Co-ordination of Flexible AC transmission system (FACTS) devices with other existing Var sources present in the network. IEEE 30 and IEEE 57 bus systems are taken as standard test systems. SPSO (Simple Particle Swarm Optimization) and other two swarm based intelligence approaches like APSO (Adaptive Particle Swarm Optimization) and EPSO (Evolutionary Particle Swarm Optimization) are used for the optimal setting of the Var sources and FACTS devices. The result obtained with the proposed approach is compared with the result found by the conventional RPP (Reactive power planning) approach where shunt capacitors, transformer tap setting arrangements and reactive generations of generators are used as planning variables. It is observed that reactive power planning with FACTS devices yields much better result in terms of reducing active power loss and total operating cost of the system even considering the investment costs of FACTS devices. [ABSTRACT FROM AUTHOR]

In the present work, GSA (gravitational search algorithm) based optimization algorithm is applied for the optimal allocation of FACTS devices in transmission system. IEEE 30 & IEEE 57 test bus systems are taken as standards. Both active and reactive loading of the power system is considered and the effect of FACTS devices on the power transfer capacity of the individual generator is investigated. The proposed approach of planning of reactive power sources with the FACTS devices is compared with other globally accepted techniques like GA (Genetic Algorithm), Differential Evolution (DE), and PSO (Particle Swarm Optimization). From the results obtained, it is observed that incorporating FACTS devices, loadability of the power system increases considerably and each generator present in the system is being able to dispatch significant amount of active power under different increasing loading conditions where the steam flow rate is maintained corresponding to the base active loading condition. The active power loss & operating cost also reduces by significant margin with FACTS devices at each loading condition and GSA based planning approach of reactive power sources with FACTS devices found to be the best among all the methods discussed in terms of reducing active power loss and total operating cost of the system under all active and reactive loading situations. [ABSTRACT FROM AUTHOR]

Reactive power source planning problem has significant role for secure and economic operation of power system. Reactive power planning problem is nothing but the proper coordination of existing Var sources which lead to loss minimization and cost economic operation of the system. In the proposed approach several bio-inspired algorithms like Particle Swarm Optimization (PSO), Evolutionary Particle Swarm Optimization (EPSO), Adaptive Particle Swarm Optimization (APSO), Hybrid Particle Swarm Optimization (HPSO) and Bacterial Foraging Algorithm (BFA) are used for the reactive power planning problem. Finally a comparison of all these techniques are made on the basis of the results obtained when applied to different standard test system. [ABSTRACT FROM AUTHOR]

Demand side management (DSM) separates elastic and inelastic loads and reorganizes a distribution system's load demand model while reducing the overall cost of the operation. This is accomplished by shifting flexible loads to hours with lower utility costs per unit. In this study, a bi-level optimization technique is used to reduce the operating costs of a low voltage microgrid system that uses battery energy storage, renewable energy sources, and fossil fuel generators while running in grid-connected mode. The load model is reorganized at the first level of optimization according to the DSM involvement level. Thereafter, the restructured load demand models are taken into account, and distributed generator scheduling ideas are percolated for reducing the microgrid system's generating costs in the second level. The optimization tool for the study was a newly established hybrid swarm intelligence algorithm that has previously been utilized to solve a variety of power system optimization challenges. For various grid participation models and grid pricing schemes, both with and without taking into account DSM, the generating cost was reduced. When 10%, 20%, and 30% DSM involvement was taken into consideration, the numerical findings reveal 25%, 50%, and 70% reduction, respectively, in costs. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fuzzy based evolutionary algorithm. [•] FACTS devices for reactive power optimization. [•] FACTS devices for minimum operating cost of a power system. [Copyright &y& Elsevier]

Abstract—This article presents a novel approach for optimal flexible AC transmission systems devices planning in an interconnected power system under different loading conditions. The static VAR compensator and thyristor-controlled series capacitor are two types of flexible AC transmission systems devices considered for optimal power system operation. In the proposed approach, a fuzzy membership function is used to determine weak nodes in the power system for the placement of static VAR compensators as a flexible AC transmission systems device. The thyristor-controlled series capacitor is the other type of flexible AC transmission systems devices for which its positions are determined by the reactive power flow in lines. The genetic algorithm is used for the optimal setting of the power system variables, including flexible AC transmission systems devices. The proposed technique is compared with other optimization methods using different globally accepted evolutionary algorithms where the nodes or point of VAR compensation is determined by eigenvalue analysis, and the amount of flexible AC transmission systems devices is determined by evolutionary techniques, such as the genetic algorithm, differential evolution, and particle swarm optimization. The superiority of the proposed fuzzy-based optimization approach is established by the results and comparative analysis with other methods. [ABSTRACT FROM PUBLISHER]

This paper presents Particle Swarm Optimization (PSO) based approach for the allocation & coordinated operation of multiple FACTS (Flexible AC Transmission System) devices for the economic operation as well as to increase power transfer capacity of an interconnected power system under different loading condition. The PSO based approach is applied on IEEE 30-bus system. The system is reactively loaded starting from base to 200 % of base load. FACTS devices are installed in the different locations of the power system and system performance is noticed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power flows in the lines. A Particle Swarm Optimization based algorithm is then applied to find the amount of magnitudes of the FACTS devices. This Particle Swarm Optimization based approach for the placement of FACTS devices Yields promising result both in terms of performance and economy which is clearly observed from the result obtained. [ABSTRACT FROM AUTHOR]

Generation of electricity comes with the emission of toxic gases into the atmosphere by the fossil fueled generators. Along with the promotion in the utilization of renewable energy sources (RES), it is also the duty of the power engineers to arrive at a compromised solution such that less emission of toxic gases occurs with economic generation of electricity. This paper proposes a balanced trade-off method for solving environment constrained economic dispatch (ECED) problems. A novel comparative analysis is performed among proposed ECED method with existing price-penalty-factor (PPF) and fractional programming (FP) methods for solving combined economic emission dispatch (CEED) problems on a 3-unit dynamic test system to sort out the method, which yields a better trade off solution between generation cost and pollutants emitted. An algorithm, following the hunting strategy of wolves, is improvised by incorporating strategies from population-based sine-cosine algorithm along with position updating methods of crows to form a robust hybrid algorithm, which was used as the optimization tool for the study. Involvement of RES diminished the generation cost to 5.5% for both economic dispatch and PPF based CEED, and 6.5% decrease in emission of pollutants was observed due to the same. The generation cost and amount of emitted pollutants, evaluated using proposed ECED approach, were much closer to the economic dispatch and emission dispatch values respectively compared to PPF based and FP based CEED solution. Furthermore, statistical analysis endorses the superiority of the proposed hybrid optimizer over other algorithms presented in the state-of-art literature. • Three different types of CEED methods are studied. • Subject test system is a 3-units RES integrated microgrid system. • Comparative analysis among the generation costs and pollutants emitted is performed. • A novel HMGWO algorithm was proposed as the optimization tool for the study. [ABSTRACT FROM AUTHOR]

Topological insulators represent a new electronic phase which comes from the topological character of the bulk wave functions in some special materials. These exotic phases can be attributed to the strong spin-orbit interaction and can be explained with the band theory of solids. Recent studies show that topological insulators (TIs) such as Bi 2 Te 3 or Bi 2 Se 3 have promising candidature for optoelectronic industry and some of these interesting properties have been already demonstrated such as strong light absorption, photocurrent sensitivity to the polarization of light, layer thickness and size dependent tuning in the band gap. Theoretically, it has been proposed that TIs based broad spectral photodetector has potential in analogy with that of a graphene based photodetector. Combining TIs with carbon-based nanomaterials provides novel and promising technique for photodetection, and can show broad spectral properties. Along this line, we have grown photodetector based on hybrid of TIs with carbon nanotubes. Efficient light absorption and electron hole pair generation has been observed under the illumination of visible (532 nm) and NIR (1064 nm) light. High photoresponsivity and photoconductive gain of 79.4 AW-1 and 185, respectively, along with very good detector response time were observed in our device under visible laser (532 nm) illumination. • Novel optical device based on Topological Insulator - Carbon Nanotubes hybrid for broadband photodetection was developed. • Efficient light absorption and electron-hole pair generation observed under illumination of visible and NIR laser light. • Excellent photodetection properties with high photoresponsivity and photoconductive gain was demonstrated by the hybrid. [ABSTRACT FROM AUTHOR]

Summary: Microgrids have lately proved to be the most efficient type of power system delivering uninterrupted power to a local area incurring negligible amount of transmission loss. Inclusion of the available renewable energy sources among the various distributed generation (DG) sources in a microgrid have decreased the emission of harmful toxic gases to a great extent. Dynamic economic dispatch indicates the economic dispatch of a microgrid allocating the timely optimal output of the distributed generation sources. However, the setup of a microgrid involves a huge amount of capital out of which installation cost, operation and maintenance cost, and depreciation cost instigated through the passing of time are a few. This paper uses three soft computing techniques viz. particle swarm optimization, differential evolution, and differential evolution with local global neighborhoods to perform a novel dynamic cost analysis of a microgrid and minimize its overall cost which includes fuel, emission, operation and maintenance cost, installation, and depreciation costs. Four different case studies are pulled off on a microgrid, and a comparative analysis is done to identify the best case. Numerical results and figures also point out the best optimization technique which was able to give the most efficient and minimal cost for the microgrid. [ABSTRACT FROM AUTHOR]

Abstract We report on high-responsivity metal-semiconductor-metal (MSM) structure based ultraviolet (UV) GaN photodetectors fabricated on various GaN nanostructures such as porous nanocolumn network (PNCN), nanowall networks (NWNs), and granular and compact thin films. Different GaN nanostructures were hetero-epitaxially grown on c-sapphire using laser molecular beam epitaxy by tuning the AlN buffer layer growth parameters. High resolution x-ray rocking curve measurements indicate that the crystalline quality of GaN critically depends on the selection of AlN buffer layer growth conditions such as type of ablation target and growth temperature. The porous GaN nanostructures revealed a nearly stress-free wurtzite structure as deduced by Raman spectroscopy measurements. Room temperature photoluminescence spectroscopy showed that the GaN films possess a near band emission (NBE) peak at ∼ 3.39 eV along with a broad yellow luminescence (YL) with maxima at 2.25 eV. For GaN PNCN and NWN structures, the NBE-to-YL emission ratio is more than an order higher compared to the GaN films. The fabricated MSM based UV-detector on GaN PNCN and NWN exhibited a high photo-responsivity of ∼27.72 and 24.8 A/W, respectively, under 2 V applied bias at room temperature. The GaN PNCN and NWN nanostructures with excellent photo-responsivity and optical quality prove to be promising candidates for the fabrication of efficient UV photodetectors due to their continuity in lateral direction, high surface area-to-volume ratio and tailored surfaces. Highlights • Laser molecular beam epitaxy of Porous GaN nanostructures on c-sapphire. • Tuning of shape and size of GaN nanostructures with AlN growth parameters. • Formation of GaN porous nanocolumn network (PNCN) and nanowall network (NWN) structures. • Fabrication of metal-semiconductor-metal based GaN UV photodetectors. • Achievement of a high UV responsivity of 27.72 A/W for GaN PNCN photodetectors. [ABSTRACT FROM AUTHOR]

Fast switching response of photodetectors is needed for many applications. Therefore, it is necessary to study the photoconductivity properties of earth abundant and cost effective materials. Till now, there are only two reports based on photoconductivity study of Cu 2 ZnSnS 4 ( CZTS) based materials. In this study, CZTSSe thin film on soda-lime glass substrate was deposited using one-step reactive sputtering from CZTSe target in presence of H 2 S followed by annealing. Optical, structural, morphological and elemental compositional analyses were carried out to characterize the CZTSSe thin film. The value of optical band gap estimated using Tauc's plot was 1.45 eV. The presence of very intense peak corresponding to (112) plane in the XRD pattern suggested growth to be oriented. Similar was the case with Raman studies. Photoconductivity study of CZTSSe thin film in visible region (excitation wavelength – 532 nm) is carried out. At a bias voltage of 5 V, response rise time and decay time in visible range for CZTSSe were 330 ms and 0.986 ms, respectively. The values of responsivity, detectivity, sensitivity (I light /I dark ) and external quantum efficiency were 14.6 mA/W, 3.5 × 10 9 Jones, 6.9363 and 3.5%, respectively. The shortest reported response decay time by CZTSSe based photodetector is the novelty of this work. This work shows the possibility of utilizing CZTSSe thin film as photodetector for various applications. [ABSTRACT FROM AUTHOR]

CdS grown by chemical bath deposition (CBD) technique is very simple, robust, economical method and has potential large scale applications in solar cells, photovoltaic, photodetectors, sensors and optoelectronic devices. Here we report channel lengths (CLs) specific broadspectral photoresponse properties of commonly grown robust CdS films by CBD. The broadspectral dependent current flow has been observed in all CLs and the rise and decay times have been measured in milliseconds for visible wavelengths (400-700nm). The rise time curves showed linear dependency when measured for CLs 300, 500 and 700nm and non-linearity was observed for CLs 7µm, 45µm and 350µm. We have noticed that decrease in channel lengths down to nanometers (300 nm) increases the response time. Three steps decay time has been noticed for all CLs. The shorter channels (nm) showed two trends in decay time, small increase for wavelengths <550nm and significant increase for wavelengths >550nm. Finally, CLs specific broadspectral photosensitivity has been investigated which indicates the device geometry and fabrication method play an important role for defining the CdS based photodetectors or simulating the characteristics of a photodetector.? [ABSTRACT FROM AUTHOR]

Kesterite is a compound semiconductor material getting huge attention due to its favorable optoelectronic properties. Here, photoconductivity properties of Cu 2 ZnSn(S,Se) 4 thin film is studied, demonstrating potential of Cu 2 ZnSn(S,Se) 4 device as low-cost, self-powered, broadband (Vis-NIR) photodetector. • Fabricated CZTSSe thin-film broadband (Vis-NIR) PD having self-powered characteristics. • Higher carrier mobility of 37.96 cm2.V−1.s−1 achieved by controlling growth parameters. • High responsivity and detectivity achieved at 532 nm laser under 500 mV applied bias. • Fast switching (on/off) speed of 82/97 ms obtained at 1064 nm laser. Photodetectors have large applications in the current ongoing pandemic. These can be used to study the growth of viruses where depending upon the concentration the light intensity will be reduced. Since the viruses grow very fast therefore a device with very low response time as well as quick recovery will be useful for this study. If the device can be made from the non-toxic materials and sizes are quite small, they can be used for in vitro studies as well. Kesterite Cu 2 ZnSn(S, Se) 4 (CZTSSe) thin film can be deposited over flexible substrates. The detectivity of even very small area device is very high with ultra-small response and recovery time. The CZTSSe PD exhibited excellent broadband (Vis-NIR) photoresponse, high responsivity of 18.0 mA.W−1, a fast rise time of 82 ms, and a decay time of 97 ms, as well as high detectivity (∼109 Jones) with favorable self-powered characteristics. This work suggests significant scientific insights for photoconductivity properties of emerging kesterite CZTSSe thin-film materials for broadband, low-cost, high-efficiency next-generation thin-film photodetectors for various optoelectronic applications including diagnostic. [ABSTRACT FROM AUTHOR]