Solar Radiation Estimation Using Data Mining Techniques for Remote Areas-A Case Study in Ethiopia

High quality of solar radiation data is essential for solar resource assessment. For remote areas this is a challenge, as often only satellite data with low spatial resolution are available. This paper presents an interpolation method based on topographic data in digital elevation model format to improve the resolution of solar radiation maps. The refinement is performed with a data mining method based on first-order Sugeno type Adaptive Neuro-Fuzzy Inference System. The training set contains topographic characteristics such as terrain aspect, slope and elevation which may influence the solar radiation distribution. An efficient sampling method is proposed to obtain representative training sets from digital elevation model data. The proposed geographic information system based approach makes this method reproducible and adaptable for any region. A case study is presented on the remote Amhara region in North Shewa, Ethiopia. Results are shown for interpolation of solar radiation data from 10 km x 10 km to a resolution of 1 km x 1 km and are validated with data from the PVGIS and SWERA projects

Development of a simplified analytical model for a passive inertial system solicited by wave motion

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThis paper presents a theoretical and experimental investigation about the modelling of a 1:45 scale prototype Wave Energy Converter (WEC). An analytical model is implemented to describe its behaviour in a wave tank. The aim is to provide a contribution to modelling tools used for WEC characterisation and design. Hydrodynamic characterisation software is avoided in favour of a simpler and more versatile design tool destined to a wider range of users. Therefore, an alternative approach is presented, based on mechanical analogies and the use of Matlab/Simulink/SimMechanics environment. This analytical model was constructed using linear wave theory, coupled with a non-linear model for the device and its power take-off system (PTO). Assumptions on incident waves and geometric properties of the device were required and implemented on the basis of literature of naval architecture, ships stabilization and control issues. Simulation results were compared and validated with those obtained in the same range of experimental tests of the prototype in wave tank. Trends and values of both investigation techniques show a good agreement, indicating the validity of the methodology adopted and leaving space for future improvements of the same. Finally, as example of application, the model was applied in a show case in order to estimate the energy yield by the WEC if scaled to real size, using Froude scaling. Results are encouraging and show the viability of the proposed design

Fault location in low-voltage distribution networks based on reflectometry - a case study

Fault location can help transport and distribution system operators in their effort of minimizing supply interruption times. Nowadays, fault location devices are widely extended in the transport grid. However, the application of these solutions to distribution networks is not a feasible option due to the high cost of this equipment. Therefore, current research is focussed on costeffective fault location techniques which are adapted to electrical distribution networks. This paper presents results of a case study, conducted with detailed simulation models of two actual low-voltage (LV) distribution grids, using PSCAD software. One is a typical rural grid with long aerial lines, while the other is a typical urban grid with shorter line lengths which are mostly installed underground. The analysis is focussed on fault location based on travelling wave theory and reflectometry methods. The simulations include distributed parameter line models and a signal injector, in order to analyse the singular effects in the waveform which are caused by the special features of the LV network. It is shown that LV networks have some unique features which are not present in medium and highvoltage grids, which makes effective fault location more challenging. Observed issues are discussed and future work is proposed in order to overcome some of them.This research was funded by the “Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación” grant number “RTC-2017-6782-3” and the European Union FEDER funds with name “LOcalización de averías, monitorización de estado y Control en redes de bAja TEnsión—LOCATE”

Modeling and simulation of time domain reflectometry signals on a real network for use in fault classification and location

Today, the classification and location of faults in electrical networks remains a topic of great interest. Faults are a major issue, mainly due to the time spent to detect, locate, and repair the cause of the fault. To reduce time and associated costs, automatic fault classification and location is gaining great interest. State-of-the-art techniques to classify and locate faults are mainly based on line-impedance measurements or the detection of the traveling wave produced by the event caused by the fault itself. In contrast, this paper describes the methodology for creating a database and a model for a complex distribution network. Both objectives are covered under the paradigm of the time-domain pulse reflectometry (TDR) principle. By using this technique, large distances can be monitored on a line with a single device. Thus, in this way a database is shared and created from the results of simulations of a real and complex distribution network modeled in the PSCADTM software, which have been validated with measurements from an experimental test setup. Experimental validations have shown that the combination of the TDR technique with the modeling of a real network (including the real injector and the network coupling filter from the prototype) provides high-quality signals that are very similar and reliable to the real ones. In this sense, it is intended firstly that this model and its corresponding data will serve as a basis for further processing by any of the existing state-of-the-art techniques. And secondly, to become a valid alternative to the already well-known Test Feeders but adapted to work groups not used to the electrical world but to the environment of pure data processing

Statistical metrics for assessing the quality of wind power scenarios for stochastic unit commitment

In power systems with high penetration of wind generation, probabilistic scenarios are generated for use in stochastic formulations of day-ahead unit commitment problems. To minimize the expected cost, the wind power scenarios should accurately represent the stochastic process for available wind power. We employ some statistical evaluation metrics to assess whether the scenario set possesses desirable properties that are expected to lead to a lower cost in stochastic unit commitment. A new mass transportation distance rank histogram is developed for assessing the reliability of unequally likely scenarios. Energy scores, rank histograms and Brier scores are applied to alternative sets of scenarios that are generated by two very different methods. The mass transportation distance rank histogram is best able to distinguish between sets of scenarios that are more or less calibrated according to their bias, variability and autocorrelation

Numerical Investigation of the Performance of Three Hinge Designs of Bileaflet Mechanical Heart Valves

Thromboembolic complications (TECs) of bileaflet mechanical heart valves (BMHVs) are believed to be due to the nonphysiologic mechanical stresses imposed on blood elements by the hinge flows. Relating hinge flow features to design features is, therefore, essential to ultimately design BMHVs with lower TEC rates. This study aims at simulating the pulsatile three-dimensional hinge flows of three BMHVs and estimating the TEC potential associated with each hinge design. Hinge geometries are constructed from micro-computed tomography scans of BMHVs. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Leaflet motion and flow boundary conditions are extracted from fluid–structure-interaction simulations of BMHV bulk flow. The numerical results are analyzed using a particle-tracking approach coupled with existing blood damage models. The gap width and, more importantly, the shape of the recess and leaflet are found to impact the flow distribution and TEC potential. Smooth, streamlined surfaces appear to be more favorable than sharp corners or sudden shape transitions. The developed framework will enable pragmatic and cost-efficient preclinical evaluation of BMHV prototypes prior to valve manufacturing. Application to a wide range of hinges with varying design parameters will eventually help in determining the optimal hinge design

A theoretical approach to the prediction of haemolysis in centrifugal blood pumps

SIGLEAvailable from British Library Document Supply Centre-DSC:DX206523 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Einsatzmöglichkeiten von simulationsunterstützten Autoklavprozessen

In diesem Beitrag werden die Einsatzmöglichkeiten von simulationsunterstützten Autoklavprozessen anhand des Virtuellen Autoklaven vorgestellt. Auf Grundlage einer zweistufigen Simulationsumgebung entsteht ein Werkzeug, das nicht nur in der Lage ist direkt messbare und qualitätsrelevante Parameter zu berechnen, sondern auch die Berechnung echtzeitfähig durchzuführen, so dass die analysierten Daten direkt in einen laufenden Autoklavprozess eingespeist werden können. Das bringt den Vorteil Prozesse vor und während der Polymerisation im Autoklaven optimal zu gestalten und somit qualitätsgesicherte, reproduzierbare Bauteile aus kohlenstofffaserverstärkten Kunststoffen (CFK) mit einer minimalen Ausschussrate zu fertigen