Browsing by Author "Das, S.K.,"

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    Ancillary Voltage Control Design for Adaptive Tracking Performance of Microgrid Coupled with Industrial Loads
    (Institute of Electrical and Electronics Engineers Inc., 2021) Sarker, S.K.,; Fahim, S.R.,; Sarker, N.,; Tayef, K.Z.,; Siddique, A.B.,; Datta, D.,; Mahmud, M.A.P.,; Ishraque, M.F.; Das, S.K.,; Sarker, M.R.I.,; Shezan, S.A.,; Rahman, Z.
    Although the utilizing of renewable energy sources (RESs) in microgrid (MG) offers a recognized solution to meet the increasing demand, it's performance depend on various meteorological factors of RESs. Again, the functioning of MGs is often affected with certain industrial load dynamics which allowing them to alter the operating region and tracking function of the MGs. The above-mentioned challenges motivate us to design the ancillary voltage control design for enabling the MGs to provide adaptive transient and tracking voltage responses over the changes of various factors like weather, consumer demand, and industrial loads. Firstly, we design an intelligent adaptive control (IAC) framework made by merging with proportional-integral (PI) regulator and artificial neural network (ANN) to sustain the regulated common bus voltage over the mentioned changes. The regulated bus voltage is forwarded to operate the industrial loads via the regulation of inverter-based secondary network (SN). A study on the variation of weather condition and consumer demand is done to show the efficacy of the IAC framework. Secondly, we propose a novel fixed control structure named model reference modified fractional-order PID (MR-F0PID) regulator to maintain the high tracking response of the MG via the control of inverter associated with the SNs. The tracking competency of this fixed control framework is analyzed over the running of a few industrial loads dynamics associated with single-phase inverter based SN and results are compared with the other related existing controllers. Moreover, a mathematical analysis for mapping the stable region is completed here to track down the closed-loop stability area. As a further study, the three-phase inverter based SN associated with several three-phase industrial load is also considered with the same DC bus and analyzed to observe the competency of the proposed fixed MR-FOPID control framework.
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    Nutrients and sediment loads in water catchments with heterogeneous land uses
    (Nova Science Publishers, Inc., 2018) Das, S.K.,; Ng, A.W.M.,; Ng, A.W.M.,
    Understanding how nutrient and sediment concentrations in leachates (e.g., agricultural runoff) vary with land uses is critical to study the current and future impacts of land use changes on catchment water quality. This chapter presents a simple procedure on how to use specific flow regimes to correlate pollutant load with land use activities in heterogeneous catchments, even in shortage of specific event-based water quality grab sample data. The procedure uses a simple baseflow separation technique and a data-based model with other readily available data and tools. The specific tasks of this study were: (1) establishment of whether there is any statistically significant difference between pollutant concentrations in water quality samples representing baseflow conditions and runoff events, (2) estimation of nutrient and sediment loads, and (3) identification of significant and major sources of pollutant loads. The proposed procedure was then applied to the Yarra River catchment in Victoria, Australia, and found to be effective, particularly in circumstances where limited time (for complex analysis) and data are available. The study found that at all monitoring stations, pollutant concentrations were significantly (p ≤ 0.01) greater in runoff events than in baseflow conditions, and the LOADEST regression models developed explained more than 85% variability in loadings. Overall, water quality and pollutant concentrations were influenced by specific flow regimes and land uses. Major pollutant loads were generated from agricultural and urban runoff, i.e., non-point sources. About 65%, 69% and 86% of annual TN, TP and TSS total loads respectively at the outlet of the catchment were delivered by runoff events where runoff event days were on average 18% and 31% only at the main stream and tributary stations respectively during the study period. © 2018 by Nova Science Publishers, Inc. All rights reserved.