نشریه تحقیقات نوین در سیستم های قدرت هوشمند
سال هشتم شماره 3 (پیاپی 19، پاییز 1398)

One of the methods of generating electricity from solar energy is using solar chimney technology. In this research we have studied four proposed physical models of solar chimney by examining Iran's climate map and selecting the appropriate region for the power plant site. This study is a numerical simulation of four physical models of solar chimney in Bam city, Kerman province. According to valid meteorological data, the behavior of all four models was evaluated on a specific day of the year. According to the results of the simulation, which includes the air velocity rate in four internal points of chimneys and the output power of each of the above mentioned models, the best and most suitable solar chimney model can be selected for the site under consideration and an appropriate estimate of the final output will be obtained.

Today, the widespread use of fuzzy controllers in electrical systems, especially, systems includes nonlinear and uncertainty terms, which are rapidly increasing. Indeed, the design of a desirable fuzzy inference system requires the correct selection of the type, number, and scope of membership functions due to fuzzifying the input and output variables of the system. But so far, no research or structural method has been introduced for the correct selection of membership functions and exclusively has been based on trial and error of the designer of the system. Considering the importance of this issue, the current paper investigated a comprehensive review of the membership functions selection in articles related to electrical systems. Finally, based on the articles reviewed and the categories carried out, suggestions for optimal selection of membership functions are presented based on the applications of electrical systems.

In industrial environments, a large amount of data is generated which in turn stores the database and data from all relevant areas such as planning, process design, materials, assembly, production, quality, process control, scheduling, error detection, shutdown, relationship management. Collects with the customer, etc. Data mining has become the tool used to gain knowledge of the industrial process of iron and steel making. Due to the rapid growth of data mining, various industries have been using data mining technology to search for hidden patterns that may be more relevant to the new windshield system, which will introduce new models to improve production quality, optimal cost of productivity and maintenance, and so on. Continuous improvement of the entire steel production process due to the avoidance of quality deficiencies and associated production improvement is an essential task of the steel producer. Therefore, the zero defect strategy is popular today and several quality assurance techniques are used to maintain it. This article attempts to identify the effective state-of-the-art sensors in the system using data mining and then to obtain a suitable model using a support vector machine to predict the system status in this article, the accuracy of more than 95% of the error states is detected.

In this paper, direct power control (DPC) was used for active and reactive power control of DFIG in constant speed reference and variable turbine speed reference based on the optimal power curve. On the other hand, wide application of nonlinear loads in power networks has caused problems such as high current harmonics. Non-linear loads act like harmonic current sources and inject harmonic currents into the supply network. The presence of harmonics in the network causes the harmonic voltage drop and causes other consumers to receive distorted supply voltage, which may cause overheating of power factor correction capacitors, motors, transformers and cables, and mal-operation of some protection devices. Since DFIG is responsible for injection of active and reactive power to the network, it is possible to compensate for the fluctuation of power due to nonlinear loads in the network by proper power injection. Therefore, in this paper, direct power control is implemented to control the power of DFIG, and also to reduce the network current harmonics in the presence of nonlinear loads by using the proper control methods through the rotor side converter and grid side convertors. In this regard, the Matlab/Simulink software is used to simulate a system including a DFIG-based wind power unit and the results are analyzed and compared in different scenarios. The results indicate that accurate and fast control of the DFIG power is along with a significant reduction of network current harmonics.

Isolation detection methods are divided into three active, passive and telecommunication categories. In most cases, passive methods are used more than other methods due to low cost, simplicity, high speed and no harmful effect on the power quality of the power system. In these methods, a parameter of the system is considered as an indicator and the system is analyzed by setting threshold values for this parameter. An island system is detected if the desired parameter exceeds the threshold values for it. The major problem with these methods is their large detection area. In this paper, a method for identifying islandization is proposed based on the decision tree algorithm. This method determines islandization by using one or more indicators used in other methods of inactive detection in terms of network complexity. This method has been tested under various possible incidents in grid-grids and various loading systems and distributed generation sources. The results indicate the fast and accurate performance of the proposed method with its inadequate detection area compared with other inactive methods of island identification.

Gearboxes are indispensable and indispensable components of power transmission systems. Mechanical gearboxes are used because of their high torque density, but problems and disadvantages such as perturbation, heat, vibration, noise, reliability, need for maintenance, lubrication and friction are all caused by these gearboxes. To replace other types of gearboxes, magnetic gearboxes replace mechanical gearboxes. The main drawback of using magnetic gearboxes is their low torque compared to mechanical gearboxes. In this study, we selected a sample of magnetic gearboxes using finite element method by 2D Maxwell software, to optimize magnetic torque. The changes made in this study to the gearbox are to investigate the effect of changing the dimensions and type of the magnets on the torque behavior of the magnetic gearbox. Finally, this study shows that magnetically transmitted torque can increase the torque of the magnets by slight variations in magnitude and type.