Optimisation of Energy Accumulation for Renewable Energy Sources

This project focuses on optimisation of energy accumulation for various types of distributed renewable energy sources. The main goal is to prepare charging – discharging strategy depending on actual power consumption and prediction of consumption and production of utilised renewable energy sources for future period. The simulation is based on real long term data measured on photovoltaic system, wind power station and meteo station between 2004 – 2021. The data from meteo station serve as the input for the simulation and prediction of the future production while the data from PV system and wind turbine are used either as actual production or as a verification of the predicted values. Various parameters are used for trimming of the optimisation process. Influence of the charging strategy, discharging strategy, values and shape of the demand from the grid and prices is described on typical examples of the simulations. The main goal is to prepare and verify the system in real conditions with real load chart and real consumption defined by the model building with integrated renewable energy sources. The system can be later used in general installations on commercial or residential buildings.

Automatic Detection of Voltage Notches using Support Vector Machine

This paper presents a comprehensive framework for voltage notch analysis and an automatic method for notch detection using a nonlinear support vector machine (SVM) classifier. A comprehensive simulation of the notch disturbance has been conducted to generate a diverse database. Based on domain knowledge and properties of power quality disturbances (PQDs), a set of characteristic features is extracted. After feature extraction, a set of most descriptive features has been selected with decision tree (DT) algorithm, and a nonlinear SVM classifier has been trained. Finally, the detection efficiency of the trained model is presented and discussed.

Detection of the initial region of the current transformer core saturation

In the first part of the paper the detailed analysis of the existing current transformer (CT) saturation detection methods with their classification is presented. A new saturation detection method has been proposed in second part of the paper. Mathematical description of the method is given. In the next section of the paper a CT model with test scheme is presented. To identify the reliability of proposed method against nose and remanent flux density experiments have been produced in the fourth section. Comparative analysis between proposed and existing methods is also given. Finally, in conclusion a detailed description of the method is given regarding its behavior with respect to remanent flux and noise

Unfavourable Reactive Power in a Rolling Mill

The electrical consumption of the rolling mill is usually very high, above 10MW, and significantly changes during the rolling process. The rolling mill drives consume not only active but also reactive inductive power. This reactive consumption is directly compensated in the rolling mill. In order to achieve feasible energy efficiency, it is necessary to maintain balance between the instantaneous reactive inductive consumption of the drives and the instantaneous capacitive consumption of the compensating devices. The results of the consumption measurements in the real working rolling mill are presented and discussed in this paper.

Wind energy system in Ambocas-Ecuador: distributed generation and energy quality

In this communication we present the construction of a wind farm, WF, with 10 MW of nominal power. This WF will increase the quantity and quality of electricity in the area of Ambocas, Loja, Ecuador, strengthen a system with many voltage drops. The place chosen is ideal, because it is long from population, in a hill side near an existing road. Wind is persistent and has a constant orientation all along the year. The generated power will be connected with the electricity system in the Portovelo Substation, which is about 12 km from the WF site. We have calculated the expected electricity production all along the year taking into account all important data to simulate successfully the WF operation in real conditions. We have also modelled the interconnexion of the WF with the substation and its effect in the 69 kV bar. Finally, a brief economical analysis of the project gives an annual average profit higher than 3.5 USD million without taxes, while the inversion would be cancelled in less than 5 years of the 20 ones planned for the WF in full operation.

Role of honeycomb structure in improving the melting process of a phase change material inside a latent heat storage unit

In this work, a numerical study is performed to analyze the impact of honeycomb structure on heat transfer within the PCM. The modeling is based on a transient calculation making it possible to analyze the phase change of the paraffin using the commercial software "Fluent" based on the enthalpy-porosity model. The results showed that the impregnation of a metal matrix in a rectangular enclosure helps to decrease the melting time and thus improve the heat transfer within the PCM.

Determination PV Module Technical Condition

The paper focuses on the determination of technical conditions and degradation of photovoltaic modules installed in grid-on operated photovoltaic systems in Ukraine and the Czech Republic. Detected malfunctions of PV modules are classified and Fault Tree Analyses (FTA) is created for particular PV modules. For assessment of the technical condition of the PV modules it is proposed to use residual resource index (RRI), that is being successfully used for determination of technical condition of transformers, breakers and synchronous generators. The main contribution is the method for the detection of photovoltaic modules condition with the use of a neuro-fuzzy network based on the experience of operational (maintenance) staff of particular plants.

Airfoil optimization for small horizontal axis wind turbine

In order to take advantage of the low wind speed found in the Colombian territory, a gradient-based optimization process (GBA) of 2 airfoils is carried out, using the Xfoil software to evaluate the interactions. The shapes chosen will be destined for the root and for the middle zone of a blade for a small horizontal axis wind turbine (sHAWT). The blade will be created from the calculation of the chord and pitch angle with the blade element momentum methodology (BEM) and the SHAWT will be tested by CFD software to check its performance. As a preliminary result, a root-bound airfoil has been obtained with a higher performance than the airfoil used as a bases.

IoT Monitoring System for Applications with Renewable Energy Generation and Electric Drives

nternet of Things IoT developed for monitoring, control, and management of sectors such as Smart Cities, Energy, Environment, Transport, Manufacture, Industrial Automation, Maritime, Healthcare, Education, etc, by interconnecting devices over internet. New sectors emerged in renewable energy systems, industrial motion drives, sensors and actuators. This article presents the design, and development of specific IoT applications for wind energy generating units, and electric drives. IoT technologies in the control systems of electric machines, mainly in applications of motor drives, and wind energy generating systems, contribute to improved monitoring, and management of performance, and to possible savings of energy. The experimental configurations upgrade laboratory infrastructure and offer new teaching and research perspectives to engineering education.

Real-Time Experimental Assessment of a New MPPT Algorithm Based on the Direct Detection of the Short-Circuit Current for a PV System

To substantially increase the efficiency of photovoltaic (PV) systems, it is important that the Maximum Power Point Tracking (MPPT) system has an output close to 100%.This process is handled by MPPT algorithms such as Fractional Open-Circuit Voltage (FOCV), Perturb and Observe (P&O), Fractional Short-Circuit Current (FSCC), Incremental Conductance (INC), Fuzzy Logic Controller (FLC) and Neural Network (NN) controllers. The FSCC algorithm is simple to be implemented and uses only one current sensor. This method is based on the unique existence of the linear approximation between the Maximum Power Point (MPP) current and the short-circuit current in standard conditions. The speed of this MPPT optimization technic is fast, however this algorithm needs to short-circuit the PV panel each time in order to obtain the short circuit current. This process leads to energy losses and high oscillations. In order to improve the FSCC algorithm, we propose a method based on the direct detection of the shortcircuit current by simply reading the output current of the PV panel. This value allows directly calculating the short circuit current by incrementing or decrementing the solar irradiation. Experimental results show time response attenuation, little oscillations, power losses reduction and better MPPT accuracy of the enhanced algorithm compared to the conventional FSCC method.