Renewable Energy Corporation of India

This Paper presents a new approach for the optimal sizing and siting of substations and network routing problem. The solution approach proposed is a nolinear programming approach. The problem has been formulated as a Quadratic Mixed Integer programming (QMIP) problem in terms of the fixed costs of the substations and lines and the present worth of the energy loss costs of the line segments. The solution to this QMIP problem is obtained in two stages. In the first stage the quadratic programming problem is solved following the procedure developed by Wolfe using simplex method and treating all the variables as continuous variables. In the second stage, a procedure has been suggested to integerize the values of the integer variables. The proposed method is validated using a numerical example.

BACKGROUND AND OBJECTIVES: To carry out a cross-sectional survey of the medical literature on laboratory research papers published later than 2012 and available in the common search engines (PubMed, Google Scholar) on the quality of statistical reporting of method comparison studies using Bland-Altman (B-A) analysis. METHODS: Fifty clinical studies were identified which had undertaken method comparison of laboratory analytes using B-A. The reporting of B-A was evaluated using a predesigned checklist with following six items: (1) correct representation of x-axis on B-A plot, (2) representation and correct definition of limits of agreement (LOA), (3) reporting of confidence interval (CI) of LOA, (4) comparison of LOA with a priori defined clinical criteria, (5) evaluation of the pattern of the relationship between difference (y-axis) and average (x-axis) and (6) measures of repeatability. RESULTS AND INTERPRETATION: The x-axis and LOA were presented correctly in 94%, comparison with a priori clinical criteria in 74%, CI reporting in 6%, evaluation of pattern in 28% and repeatability assessment in 38% of studies. CONCLUSIONS: There is incomplete reporting of B-A in published clinical studies. Despite its simplicity, B-A appears not to be completely understood by researchers, reviewers and editors of journals. There appear to be differences in the reporting of B-A between laboratory medicine journals and other clinical journals. A uniform reporting of B-A method will enhance the generalizability of results.

Water oxidation has become very popular due to its prime role in water splitting and metal-air batteries. Thus, the development of efficient, abundant, and economical catalysts, as well as electrode design, is very demanding today. In this review, we have discussed the principles of electrocatalytic water oxidation reaction (WOR), the electrocatalyst and electrode design strategies for the most efficient results, and recent advancement in the oxygen evolution reaction (OER) catalyst design. Finally, we have discussed the use of OER in the Oxygen Maker (OM) design with the example of OM REDOX by Solaire Initiative Private Ltd. The review clearly summarizes the future directions and applications for sustainable energy utilization with the help of water splitting and the way forward to develop better cell designs with electrodes and catalysts for practical applications. We hope this review will offer a basic understanding of the OER process and WOR in general along with the standard parameters to evaluate the performance and encourage more WOR-based profound innovations to make their way from the lab to the market following the example of OM REDOX.

In this paper, optimal cooperative operational planning of distributed energy resources (DER) in an active distribution network (ADN) with soft open points (SOP) has been investigated. To do so, a new two-layer coordinated optimization framework ADN has been proposed considering SOP. In the upper layer, the location and sizing of the DERs and SOPs has been optimised. While inner layer executes simultaneous optimal functioning of volt/var control (VVC) devices, remote controlled switches (RCS), DERs, and SOPs. The main objective of proposed methodology is to reduce total investment cost of DERs and SOPs as well as operating costs of the system over the planning horizon. Besides, objective function considers the cost of energy not served (ENS), the cost of substation-purchased electricity, and the cost of carbon emissions. Meanwhile, a stochastic module has been employed to address high-level uncertainties associated to renewables and load demands. Besides, the effects of distribution network reconfiguration (DNR) and conservation voltage reduction (CVR) have been taken into account. For various instances, the suggested framework was implemented on an IEEE 119-bus distribution system and solved using a proposed hybrid optimization solver. The efficacy of proposed DER with SOP methodology has been validated on various cases and also tested on sudden external disturbances such as under voltage and over voltage problem conditions. When compared to standard planning schemes, the test results show that it is beneficial in boosting system efficiency, increasing reliability, and lowering the carbon footprint of distribution systems.

This paper presents results from eight field studies in Asia and Africa on the emissions performance of 16 stove/fuel combinations measured during normal cooking events in homes. Characterizing real-world emissions performance is important for understanding the climate and health implications of technologies being promoted as alternatives to displace baseline cooking stoves and fuels. Almost all of the stove interventions were measured to have substantial reductions in PM2.5 and CO emissions compared to their respective baseline technologies (reductions of 24–87% and 25–80%, for PM2.5 and CO emission rates, respectively), though comparison with performance guidance from the World Health Organization (WHO) and the International Organization for Standardization (ISO) suggests that further improvement for biomass stoves would help realize more health benefits. The emissions of LPG stoves were generally below the WHO interim PM2.5 emissions target (1.75 mg/min) though it was not clear how close they were to the most aspirational ISO (0.2 mg/min) or WHO (0.23 mg/min) targets as our limit of detection was 1.1 mg/min. Elemental and organic carbon emission factors and elemental-to-total carbon ratios (medians ranging from 0.11 to 0.42) were in line with previously reported field-based estimates for similar stove/fuel combinations. Two of the better performing forced draft stoves used with pellets—the Oorja (median ET/TC = 0.12) and Eco-Chula (median ET/TC = 0.42)—were at opposite ends of the range, indicating that important differences in combustion conditions can arise even between similar stove/fuel combinations. Field-based tests of stove performance also provide important feedback for laboratory test protocols. Comparison of these results to previously published water boiling test data from the laboratory reinforce the trend that stove performance is generally better during controlled laboratory conditions, with modified combustion efficiency (MCE) being consistently lower in the field for respective stove/fuel categories. New testing approaches, which operate stoves through a broader range of conditions, indicate potential for better MCE agreement than previous versions of water boiling tests. This improved agreement suggests that stove performance estimates from a new ISO laboratory testing protocol, including testing stoves across low, medium, and high firepower, may provide more representative estimates of real-world performance than previously used tests. More representative results from standardized laboratory testing should help push stove designs toward better real-world performance as well as provide a better indication of how the tested technologies will perform for the user.

The soiling of solar panels from dry deposition affects the overall efficiency of power output from solar power plants. This study focuses on the detection and monitoring of sand deposition (wind-blown dust) on photovoltaic (PV) solar panels in arid regions using multitemporal remote sensing data. The study area is located in Bhadla solar park of Rajasthan, India which receives numerous sandstorms every year, carried by westerly and north-westerly winds. This study aims to use Google Earth Engine (GEE) in monitoring the soiling phenomenon on PV panels. Optical imageries archived in the GEE platform were processed for the generation of various sand indices such as the normalized differential sand index (NDSI), the ratio normalized differential soil index (RNDSI), and the dry bare soil index (DBSI). Land surface temperature (LST) derived from Landsat 8 thermal bands were also used to correlate with sand indices and to observe the pattern of sand accumulation in the target region. Additionally, high-resolution PlanetScope images were used to quantitatively validate the sand indices. Our study suggests that the use of freely available satellite data with semiautomated processing on GEE can be a useful alternative to manual methods. The developed method can provide near real-time monitoring of soiling on PV panels cost-effectively. This study concludes that the DBSI method has a comparatively higher potential (89.6% Accuracy, 0.77 Kappa) in the detection of sand deposition on PV panels as compared to other indices. The findings of this study can be useful to solar energy companies in the development of an operational plan for the cleaning of PV panels regularly.

An analysis is performed to study the MHD flow of an electrically conducting, incompressible, viscous fluid past a semi-infinite vertical plate with mass transfer, under the action of transversely applied magnetic field is carried out. The heat due to viscous dissipation and the induced magnetic field are assumed to be negligible. The dimensionless governing equations are unsteady, two-dimensional, coupled and non-linear partial differential equations. A most accurate, unconditionally stable and fast converging implicit finite difference scheme is used to solve the non-dimensional governing equations. The effects of external cooling (Gr > 0) of the plate by the free convection are studied.

Solar radiation measurements as most time-series data suffer from interruptions. Gaps may occur due to loss of power, misalignment, failure of instruments, insufficient cleaning or other reasons. Quality check procedures identify such malfunctioning and mark untrustworthy data by flags. Even well maintained stations with good equipment usually show gaps. In the case of the Indian SRRA network with its 51 stations operating since 2011, typically around 7% of the data are flagged as potentially erroneous or missing. Duration of gaps ranges from few minutes to several days. However many applications such as solar energy performance simulations need continuous time-series. Therefore it is required to fill the measurement gaps with reasonable data. Depending on duration and type of missing parameters various procedures can be used to fill gaps. This paper describes a set of procedures called 'basic gap filling' for solar irradiance, which can be applied without having available additional data. From the over-determined set of global, diffuse and direct radiation a single missing parameter can be calculated from the other two. When two or more solar irradiance components are missing for short gaps, clearness indices are derived to calculate the missing irradiance components. Basic gap filling procedure is applied as part of the SRRA/SolMap projects. The accuracy of the applied basic gap filling methodology is tested and the results show a mean bias of ca. 3 % over GHI, DNI and DHI over all types of gaps.

This article presents the experimental results of the underwater performance of amorphous silicon (a-Si) thinfilm photovoltaic (TFPV) module. Electrical performance characteristics (current, voltage, power input, power output, and power conversion efficiency) of a-Si TFPV are evaluated considering the two installation conditions of Submerged Photovoltaics (SPV): shallow and deep waters. Experimental results showed that the a-Si TFPV could convert sun energy into electricity even in underwater environments. It is observed that there is a little drop in power outputs in deep waters than to shallow waters due to the variation in incident sunlight on to the photovoltaic (PV) module. Based on the observations, few possible applications for underwater PV system are explored. The article is concluded by highlighting few critical points for future research.

The outbreak of novel coronavirus, which is declared as a ‘Global Pandemic’ by the World Health Organization (WHO), has affected around 210 countries and India is not an exception. It is an unprecedented ‘public health emergency’ and therefore, it is important that individuals should not fall into a prolonged depression or any other unhealthy psychological condition. Being concerned about the population at risk, the current study thus investigates how Big Five personality model can help in building emotional resilience during pandemic conditions. The current study thus investigates a sample of 254 adults at Delhi, selected through purposive sampling. Cluster analysis and stepwise regression analysis were conducted to establish the relationship and identify the significant personality traits required for building emotional resilience. The cluster analysis showed three main personality types (resilient, overcontrollers, and emotionally dysregulated) and further stepwise regression showed that individuals high on conscientiousness, openness and neuroticism were found to be associated with more change in emotional resilience. The findings thus achieved are a step towards psychological health of the individuals at risk. Additionally, the results of the study may be added to the psychological first aid (PFA) guide as reference point. Bearing in mind the potential for future research, it is recommended that longitudinal studies should be conducted, and the relationship should also be examined in the presence of other variables such as culture, life stressors and gender.

In this review, analysis of triple-impact vapour ingestion refrigeration framework involving a high, medium and low-temperature generator is characterized. This review suggests the solar power-related triple impact vapour retention refrigeration for heating and cooling applications in dairy industries that should be developed. In this review, the paper investigates solar heat and cooling is practised in modern dairy applications. With improved advancements and scaled-down costs, the solar-powered energy guarantees to reduce power charges builds countries’ energy security through reliance on a special, unfathomable resource, redesigned practicality, limited defilement, cut down the costs of diminishing an unsafe barometrical deviation, and keeps oil subordinate costs lower than something different. The important source of heating is considered from solar-based by using different solar oriented heat advancements. The results indicate that solar power-related triple impact vapour retention refrigeration for heating and cooling applications in dairy industries. Different operating temperatures are measured during the implementation and find an optimal food processing condition in the dairy industry. Thus, this observed study gives hands to develop an efficient renewable system for processing industrial dairy operation using solar power. Implementing renewable energy sources in the dairy industries promotes overall energy consumption and lower the total expenditure of industrial processing, respectively.

Global initiatives to reduce negative impact on environment and strategies to mitigate climate change issues have led to increased stress on clean and green energy. However, this change for good is accompanied by new challenges to power system engineers, especially protection engineers. Traditional protection philosophies designed for grids dominated by synchronous generators have now become inadequate to protect modern grids with high penetration of inverter-based renewable energy resources. The peculiar fault current characteristics, controlled by converter topologies, control algorithms, grid codes and fault ride through characteristics have introduced challenges to the most prominently employed distance protection. This paper analyses the impact of inverter-based resources on the performance of stepped distance protection, including Zone 1, Zone 2 and Zone 3. Extensive testing is conducted using transmission line system modelled in PSCAD, and observations are discussed. Certain insights on potential solution strategies are also provided. Further, performance of fault location function, which is an integral part of commercial distance relays, is also analysed for the renewables-integrated grid. Single-ended as well as double-ended fault location algorithms are studied, and observations are discussed.

In the Solar Radiation Resource Assessment (SRRA) project of the Ministry of New and Renewable Energy, India a network of 51 automatic solar radiation monitoring stations have been set up across India. Such a large number of high-quality solar radiation stations with sensitive instruments require efficient procedures for regularly controlling proper operation of each station, the quality of the measured data, and its overall performance. Following best practices for quality assessment tests, such routines are implemented at the SRRA archiving and processing center. Various quality control tests are applied that check the plausibility of data, differentiate trustworthy data from likely erroneous data and flag them accordingly. A data flagging system is implemented to identify, differentiate and quantify different types of errors. These quality-checked, flagged data are then used by routines to create monthly reports and data products. This paper describes the automated quality check system implemented and evaluates the performance of stations since their erection in 2011. This paper also describes first experiments to validate the functionality of the applied quality checks. The quality flag statistics of all 51 stations reveals that some stations are performing very well and others need more attention to improve. In the period from January 2012 to March 2013 on an average over all 51 stations, 92% of the solar radiation data are classified as correct. Around 4% of solar radiation data do not pass the coherence test. Tracking errors are observed during 0.3 % of the time averaged over all 51 stations. This analysis helps to further improve the operation of this network and find ways for better-automatized quality checks.

A solar-biogas hybrid dryer was designed, developed and tested for onion drying with a capacity of 8 kg/batch. Solar energy was utilized as primary energy for onion drying in a greenhouse type drying chamber (direct solar) and biogas powered air heater used as a supplementary heat source for continuous operation. The hybrid dryer consists of greenhouse type drying chamber, concentric pipe air heater and biogas burner. The greenhouse type drying chamber has floor area of 1300 mm×900 mm and collector area of 3 m2. The dryer was operated as a solar dryer during normal sunny day and hybrid mode whenever sunlight is insufficient to maintain desired 60°C inside the drying chamber. The results indicated that the moisture content of onion slices reduced from 80.06% (wb) to 9.88% (wb) in 12 hours in hybrid mode drying. A biogas powered air heater operated for 3 hours in a day with effectiveness of 0.87 and biogas burner efficiency of 47.59%. The dryer was techno-economically feasible with a benefit cost ratio of 1.12 and payback period of 2.1 years.

Engineering Pd–In2O3 interaction is key to developing catalysts with the desired CO2 hydrogenation activity toward methanol synthesis. Here, the crystalline phase of In2O3 nanospheres was tuned by changing the calcination temperature, which was found to affect the Pd–In2O3 interaction and thus the supported Pd states and CO2 hydrogenation performance of the prepared Pd/In2O3-a catalysts (where a refers to the calcination temperature for preparing In2O3). The fresh Pd/In2O3-a catalysts show varied initial activities, and after the induction period, their performance stabilized though being different. During the 100 h catalysis, catalyst microstructures changed, showing Pd aggregation and Pd–In alloying, which was related to the nature of the crystalline phase of In2O3. The hexagonal (h-In2O3) phase in Pd/In2O3-400 possesses concentrated surface OH groups and limited mobility. The relatively poor mobility limits Pd–In alloying, which possibly suppresses the hydrogen spillover effect, causing low CO2 conversion (8%) and methanol selectivity (45%) under steady-state conditions at 5 MPa and 300 °C. Conversely, the cubic In2O3 (c-In2O3) phase promotes Pd–In alloying and modifies Pd–In2O3 interaction during the reaction. The activity data show that Pd/In2O3-600 with the mixed phases of In2O3 (h/c-In2O3) demonstrated appropriate Pd–In2O3 interaction, leading to the Pd core InOx shell structure with the comparatively best methanol selectivity of about 65% at steady state. Conversely, Pd/In2O3-800 with the pure cubic In2O3 (c-In2O3) phase and a relatively low specific surface area of 16 m2 g–1 encourages the sintering of Pd and thereby the formation of homogeneous Pd–In alloys, having a moderate methanol selectivity of about 50%. These findings highlight the importance of the In2O3 crystal phase engineering in the catalytic CO2 hydrogenation over Pd/In2O3 catalysts and the dynamics of Pd–In interactions, which affect the methanol yield.

The dynamic reactive power (VAr) requirements limits the applications of self-excited induction generators (SEIG) because of poor voltage regulation even at constant speeds. Fixed and varying VAr compensators with conventional devices (such as synchronous condensers, shunt capacitors, series capacitors) have inherent problems like sluggish response, undue overvoltage, switching transients, sub-synchronous resonance, etc. In this paper, application of an advanced controlled series compensator (ACSC) for the voltage control of SEIG at different speeds is discussed. An ACSC-SEIG system is modeled and analysed. The theoretical results are supported with experimental results in order to establish the effectiveness of the proposed scheme.

This study looks into artificial intelligence methods for scaling solar power systems, such as standalone, grid-connected, and hybrid systems, in order to lessen environmental effect. When all essential information is provided, conventional sizing methods may be a feasible alternative. It is impossible to apply typical procedures in instances where data is unavailable. The new suggested artificial intelligence model employing multilayered perceptrons is employed for sizing solar systems, and this model functions on current photovoltaic modules that incorporate hybrid-sizing models; so, they should not be rejected entirely. In this work, the convergence speed of the proposed model for single diode, two diodes, and three diodes are the comparison factors to estimate the performance of the proposed model.

Copper Zinc Tin Sulfide (Cu2ZnSnS4 or CZTS) is gaining much attention recently as a potential light absorber alternative to CuInGaSe2 due to its suitable energy band gap ∼1.5 eV with p-type conductivity, high optical absorption coefficient of ∼105 cm−1. Moreover, all its constituents are abundant in the crust of the earth and environmentally harmless. In the present investigation, CZTS thin films were prepared using simple two step process of, sulfurization of sequentially sputtered stack, Glass/Zn/Sn/Cu (hereafter CTZ) metallic precursors on soda lime glass substrate held at temperature 200 °C. The sputter power was optimized individually for Zn, Sn, and Cu layers. The sputtered CTZ precursors were annealed at different temperatures in the range, 300–550 °C with an increment of 50 °C for 2 h in the ambience of vaporized elemental sulfur. The XRD pattern revealed that the films sulfurized in the temperature range 300–400 °C showed various spurious (binary and ternary) phases and the films sulfurized at 450 °C exhibited a clear phase corresponding to CZTS that becomes predominant at 500 °C. The optimized (500 °C) CZTS thin films showed kesterite structure with (112) preferred orientation. The sharp Raman shift centered at 336 cm−1 confirms the single phase CZTS for the precursors sulfurized at 500 °C. From the transmittance measurements, the energy gap is found to be 1.62 eV for optimized CZTS films. The optical profilometer studies indicated an increase in the surface roughness with the sulfurization temperature. AFM measurements revealed compact morphology with pyramidal texture.

Inverter based renewables (IBR) can adversely influence the reliability of distance relay which is the most ubiquitous form of protection for long high voltage transmission is endangered. Especially, distance protection of lines which are connected directly at the point of connection (POC) of the IBR are more prone to failures. In this paper, we extend a more generic discussion on issues with distance relays by including relays which are even downstream to the POC. This analysis is important from the perspective of reliable operation of a coordinated system of distance relays. The paper also presents a mitigation approach which can potentially enhance relay effectiveness without requiring any new information or infra-structural changes to the traditional implementation. The proposed solution can be implemented as a modification of the existing algorithms. We use numerical simulations of a modified IEEE 39 bus test system to analyze and demonstrate.

Single-ended fault location accuracy is adversely influenced by integration of the inverter based renewable resources (IBRs). In this paper, we cover a more generic examination of performance of single-ended fault locator for lines connected with IBRs. This analysis is used for understanding the causes of high fault location error for lines with IBRs. This information can be used for designing accurate single-ended fault locator for IBR connected networks. The paper also presents a mitigation approach which has potential improvement in fault location accuracy by using remote terminal current. The remote current is readily available, as most of the IBR connected lines are employed by differential relays as main protection. The proposed mitigation approach can be implemented in the existing line differential protection IEDs (Intelligent Electronic Devices). The approach is demonstrated using EMTDC simulation of a 220-kV, 200km transmission line connected with IBRs. Validation with field data confirms the accuarcy of proposed mitigation approach.