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Journal articles on the topic 'Generators'
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1
Mato Mišković, Marija Mirošević, and Mateo Milković. "ANALYSIS OF SYNCHRONOUS GENERATOR ANGULAR STABILITY DEPENDING ON THE CHOICE OF THE EXCITATION SYSTEM." Journal of Energy - Energija 58, no. 4 (September 16, 2022): 430–45. http://dx.doi.org/10.37798/2009584308.
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The paper elaborates on the mathematical model of the electric power system with several synchronous generators and in this model the generators are presented by a non-linear mathematical model. By applying such a model, the impact of the manner of supplying the excitation system on the generator’s angular stability was researched in the circumstances of occurrence of a short circuit in the network. The established model enables the analysis of the generator’s stability in the circumstances of extensive disruptions in the electric power system for the case of the generator with separate excitation and the generator with self-excitation. Research results can be useful when making the decision on the choice of the generator excitation type, when renewing the existing and building new generators.
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Pavlović, Jelena, Bojan Radojičić, Lazar Stančić, Jasna Dragosavac, Sava Dobričić, and Žarko Janda. "Algorithm of reactive power dispatching "per generator" realization on TPP Nikola Tesla A." Zbornik radova Elektrotehnicki institut Nikola Tesla, no. 32 (2022): 113–23. http://dx.doi.org/10.5937/zeint32-41760.
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The algorithm of reactive power dispatching "per generator" realization is presented in the paper. Dispatching "per generator" and "per grid" are two modes of reactive power dispatching used by coordinated reactive power and voltage regulator (GRRS). Reactive power dispatching "per generator" ensures equal heating of the generators, while dispatching "per grid" ensures maximal reactive power reserve when generated reactive power either increases, or decreases. Reactive power dispatching "per generator" is more complex for realization because the dispatching criterion may have wider generator's reactive power operation area than the working capability curve. In these cases, the additional limiting of the generator reactive power is necessary, while other generators take over the remaining reactive power, still considering the reactive power dispatching criteria "per generator" and the limits of the remaining generators. Both reactive power dispatching modes are presented in two examples, while operating near and far from the limit area. Eventually, as the verification of the algorithm and its realization, the operating results of GRRS while dispatching "per generator" is active, are presented.
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Labuschagne, Casper J. J., and Maarten J. Kamper. "On the Design and Topology Selection of Permanent Magnet Synchronous Generators for Natural Impedance Matching in Small-Scale Uncontrolled Passive Wind Generator Systems." Energies 15, no. 5 (March 4, 2022): 1888. http://dx.doi.org/10.3390/en15051888.
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Small-scale uncontrolled passive wind generator systems are an attractive solution for rural energy generation because of the system’s reliability and low cost. However, designing these uncontrolled wind generators for good power matching with the wind turbine is challenging and often requires external impedance matching. In this paper, permanent magnet generators with different stator and rotor structures were investigated and designed to increase the generator’s synchronous inductance for a natural impedance matching. For the design methodology, multi-objective optimisation was used to design the generators for near-maximum turbine power matching, whereby internal impedance matching was reached as much as possible. It was shown that altering the placement and orientation of the permanent magnets in the rotor is a viable method to achieve the desired impedance matching; however, these generators do not have the best performance. It was found that the surface-mounted permanent magnet generator with semi-closed slots was the optimum topology. An optimised generator prototype was tested for the experimental validation. All designs were verified by comparing the results of 2D and 3D finite-element analysis.
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Maksymovych, Volodymyr, Mariia Shabatura, Oleh Harasymchuk, Ruslan Shevchuk, Pawel Sawicki, and Tomasz Zajac. "Combined Pseudo-Random Sequence Generator for Cybersecurity." Sensors 22, no. 24 (December 11, 2022): 9700. http://dx.doi.org/10.3390/s22249700.
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Random and pseudo-random number and bit sequence generators with a uniform distribution law are the most widespread and in demand in the market of pseudo-random generators. Depending on the specific field of application, the requirements for their implementation and the quality of the generator’s output sequence change. In this article, we have optimized the structures of the classical additive Fibonacci generator and the modified additive Fibonacci generator when they work together. The ranges of initial settings of structural elements (seed) of these generators have been determined, which guarantee acceptable statistical characteristics of the output pseudo-random sequence, significantly expanding the scope of their possible application, including cybersecurity. When studying the statistical characteristics of the modified additive Fibonacci generator, it was found that they significantly depend on the signal from the output of the logic circuit entering the structure. It is proved that acceptable statistical characteristics of the modified additive Fibonacci generator, and the combined generator realized on its basis, are provided at odd values of the module of the recurrent equation describing the work of such generator. The output signal of the combined generator has acceptable characteristics for a wide range of values of the initial settings for the modified additive Fibonacci generator and the classic additive Fibonacci generator. Regarding the use of information security, it is worth noting the fact that for modern encryption and security programs, generators of random numbers and bit sequences and approaches to their construction are crucial and critical.
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Yosua Alvin Adi Soetrisno, Bambang Winardi, and Enda Wista Sinuraya. "Generator protection system with reverse power relay on 1000 KVA 'Cummins' diesel generator at Cepu Human Resources Development Center." World Journal of Advanced Research and Reviews 14, no. 1 (April 30, 2022): 377–84. http://dx.doi.org/10.30574/wjarr.2022.14.1.0343.
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Each generator is designed to create a certain amount of electricity. However, there are situations when the generator cannot handle the current load. The solution is to employ two or more generators to produce as much power as the number of generators operating simultaneously or synchronizing (parallel generator). Several parameters must be configured throughout the synchronization process, including the phase sequence, voltage, frequency, and phase angle, which must be the same. An operation failure can occur if one of the prerequisites is not fulfilled, resulting in reverse power. The motoring condition is a condition that occurs when the primary mover of a parallel generator fails. A reverse power protection mechanism is required to prevent this motoring. When one of the generator's prime movers fails or the operation fails, the voltage and load will drop. The other generator then feeds another generator. The reverse power relay instructs the generator's main circuit breaker to open the circuit so that no additional equipment is harmed. This research aims to investigate and comprehend the reverse power relay protection system's use.
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Yosua Alvin Adi Soetrisno, Bambang Winardi, and Enda Wista Sinuraya. "Generator protection system with reverse power relay on 1000 KVA 'Cummins' diesel generator at Cepu Human Resources Development Center." World Journal of Advanced Research and Reviews 14, no. 1 (April 30, 2022): 377–84. http://dx.doi.org/10.30574/wjarr.2022.14.1.0343.
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Each generator is designed to create a certain amount of electricity. However, there are situations when the generator cannot handle the current load. The solution is to employ two or more generators to produce as much power as the number of generators operating simultaneously or synchronizing (parallel generator). Several parameters must be configured throughout the synchronization process, including the phase sequence, voltage, frequency, and phase angle, which must be the same. An operation failure can occur if one of the prerequisites is not fulfilled, resulting in reverse power. The motoring condition is a condition that occurs when the primary mover of a parallel generator fails. A reverse power protection mechanism is required to prevent this motoring. When one of the generator's prime movers fails or the operation fails, the voltage and load will drop. The other generator then feeds another generator. The reverse power relay instructs the generator's main circuit breaker to open the circuit so that no additional equipment is harmed. This research aims to investigate and comprehend the reverse power relay protection system's use.
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Magaji, Nuraddeen, and Bashir Umar. "Application of Power System Stabilizer on Stability Studies." Applied Mechanics and Materials 793 (September 2015): 149–53. http://dx.doi.org/10.4028/www.scientific.net/amm.793.149.
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This paper discusses the effect of placing a power system stabilizer (PSS) at various generators for stability studies in a large power system. The damping control for the New-England 39-bus system was discussed. The effect of PSS in damping the electromechanical modes on different generator was studied. The PSS takes only a generator’s speed as input, and feeds it, after modification, to the voltage reference input of the generator’s excitation system. The results by placing a power system stabilizer on eight generators of the 39-bus system were found to be stable satisfactorily damped
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Iavich, Maksim, Tamari Kuchukhidze, Giorgi Iashvili, and Sergiy Gnatyuk. "Hybrid quantum random number generator for cryptographic algorithms." RADIOELECTRONIC AND COMPUTER SYSTEMS, no. 4 (November 29, 2021): 103–18. http://dx.doi.org/10.32620/reks.2021.4.09.
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The subject matter of the article is pseudo-random number generators. Random numbers play the important role in cryptography. Using not secure pseudo-random number generators is a very common weakness. It is also a fundamental resource in science and engineering. There are algorithmically generated numbers that are similar to random distributions but are not random, called pseudo-random number generators. In many cases the tasks to be solved are based on the unpredictability of random numbers, which cannot be guaranteed in the case of pseudo-random number generators, true randomness is required. In such situations, we use real random number generators whose source of randomness is unpredictable random events. Quantum Random Number Generators (QRNGs) generate real random numbers based on the inherent randomness of quantum measurements. The goal is to develop a mathematical model of the generator, which generates fast random numbers at a lower cost. At the same time, a high level of randomness is essential. Through quantum mechanics, we can obtain true numbers using the unpredictable behavior of a photon, which is the basis of many modern cryptographic protocols. It is essential to trust cryptographic random number generators to generate only true random numbers. This is why certification methods are needed which will check both the operation of the device and the quality of the random bits generated. The goal of the research is also to develop the model of a hybrid semi self-testing certification method for quantum random number generators (QRNG). The tasks to be solved are to create the mathematical model of a random number generator, which generates the fast random numbers at a lower cost. To create the mathematical model of a hybrid semi self-testing certification method for quantum random number generators. To integrate a hybrid semi self-testing certification method to the hybrid random number generator. the methods used are mathematical optimization and simulation. The following results were obtained: we present the improved hybrid quantum random number generator, which is based on QRNG, which uses the time of arrival of photons. The model of a hybrid semi self-testing certification method for quantum random number generators (QRNG) is offered in the paper. This method combines different types of certification approaches and is rather secure and efficient. Finally, the hybrid certification method is integrated into the model of the new quantum random number generator. Conclusions. The scientific novelty of the results obtained is as follows: 1. The hybrid quantum random number generator is offered, which is based on QRNG, which uses the time of the arrival of photons. It uses the simple version of the detectors with few requirements. The hybrid QRNG produces more than one random bit per the detection of each photon. It is rather efficient and has a high level of randomness. 2. The hybrid semi self-testing certification method for quantum random number generators (QRNG) is offered. The Self-testing, as well as device-independent quantum random number generation methods, are analyzed. The advantages and disadvantages of both methods are identified. Based on the result the hybrid method is offered. 3. The hybrid semi self-testing certification method for quantum random number generators is integrated into the offered model of the quantum random number generator. The paper analyzes its security and efficiency. The paper offers to use the new random number generator in the crypto-schemes.
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Shaker, Noor, and Mohamed Abou-Zleikha. "Alone We Can Do So Little, Together We Can Do So Much: A Combinatorial Approach for Generating Game Content." Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment 10, no. 1 (June 29, 2021): 167–73. http://dx.doi.org/10.1609/aiide.v10i1.12729.
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In this paper we present a procedural content generator using Non-negative Matrix Factorisation (NMF). We use representative levels from five dissimilar content generators to train NMF models that learn patterns about the various components of the game. The constructed models are then used to automatically generate content that resembles the training data as well as to generate novel content through exploring new combinations of patterns. We describe the methodology followed and we show that the generator proposed has a more powerful capability than each of generator taken individually. The generator's output is compared to the other generators using a number of expressivity metrics. The results show that the proposed generator is able to resemble each individual generator as well as demonstrating ability to cover a wider and more novel content space.
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Tomczyk, Krzysztof. "Influence of Monte Carlo generations applied for modelling of measuring instruments on maximum distance error." Transactions of the Institute of Measurement and Control 41, no. 1 (February 26, 2018): 74–84. http://dx.doi.org/10.1177/0142331217753062.
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The paper presents a study of the influence of Monte Carlo (MC) generations, applied for modelling measuring instruments, on the maximum distance error. This modelling refers to the frequency domain and is based on the weighted least-squares (WLS) method. The MC generations were produced by the four pseudo-random number generators that are directly related to a Gaussian distribution. These generators are: Basic Box-Muller, Polar Box-Muller, Monty Python and Ratio of Uniforms. Thus, the main task of this paper is an assessment of the influence of the MC generations provided by these generators on the values of error. The effect of generator selection on the model parameters and associated uncertainties was also considered. The numerical calculations were carried out for the accelerometer PCB393B05 that was chosen as being examples of measuring instruments intended for the measurement of acceleration.
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Hwang, Yu, Issac Sim, Young Sun, Heung-Jae Lee, and Jin Kim. "Game-Theory Modeling for Social Welfare Maximization in Smart Grids." Energies 11, no. 9 (September 3, 2018): 2315. http://dx.doi.org/10.3390/en11092315.
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In this paper, we study the Stackelberg game-based evolutionary game with two players, generators and energy users (EUs), for monetary profit maximization in real-time price (RTP) demand response (DR) systems. We propose two energy strategies, generator’s best-pricing and power-generation strategy and demand’s best electricity-usage strategy, which maximize the profit of generators and EUs, respectively, rather than maximizing the conventional unified profit of the generator and EUs. As a win–win strategy to reach the social-welfare maximization, the generators acquire the optimal power consumption calculated by the EUs, and the EUs obtain the optimal electricity price calculated by the generators to update their own energy parameters to achieve profit maximization over time, whenever the generators and the EUs execute their energy strategy in the proposed Stackelberg game structure. In the problem formulation, we newly formulate a generator profit function containing the additional parameter of the electricity usage of EUs to reflect the influence by the parameter. The simulation results show that the proposed energy strategies can effectively improve the profit of the generators to 45% compared to the beseline scheme, and reduce the electricity charge of the EUs by 15.6% on average. Furthermore, we confirmed the proposed algorithm can contribute to stabilization of power generation and peak-to-average ratio (PAR) reduction, which is one of the goals of DR.
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Kamoliņš, Edmunds. "The Comparative Analysis of Inductor and Reluctance Wind Generators." Scientific Journal of Riga Technical University. Power and Electrical Engineering 25, no. 25 (January 1, 2009): 39–42. http://dx.doi.org/10.2478/v10144-009-0008-0.
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The Comparative Analysis of Inductor and Reluctance Wind GeneratorsIn the presented work two designs of brushless generators are compared: inductor and reluctance. Both designs are multipolar and also can be applied as directly driven wind generators. Both one and the second designs are basically similar, but in the inductor generator are windings of excitation or permanent magnets which complicate a design, increase consumption of the copper and energy losses. In work shown that reluctance generator has no winding of excitation, it is simple and more reliable, it has less weight. It's more competitive for use in low power wind plants.
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Cheng, Siwei, and Thomas Habetler. "Using Only the DC Current Information to Detect Stator Turn Faults in Automotive Claw-Pole Generators." Industrial Electronics, IEEE Transactions on 60, no. 8 (April 2013): 3462–71. http://dx.doi.org/10.1109/tie.2012.2205353.
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The stator turn-to-turn short circuit is an important type of fault in automotive claw-pole generators. In a typical vehicle electric power system, the built-in rectifier of the generator makes it difficult to access the ac current or voltage information, rendering conventional sequence-component-based fault-detection methods useless. To detect such fault using only the available sensor information, a dynamic model of the claw-pole generator with stator turn faults is derived in this paper to analyze how the fault would interact with the connected battery and the static full-bridge rectifier and how it would affect the generator's output voltage and current. It is found that, in the rectified generator output current, the harmonic at one-third of the rectifier ripple frequency is a robust signature of the stator turn fault. The performance of the stator turn-fault detector is demonstrated by extensive experimental results. Although the fault detector is originally proposed for claw-pole generators, it is also applicable to most polyphase ac generators with a dc-link rectifier.
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Kadiman, Sugiarto, Arif Basuki, and Mytha Arena. "The Dynamic of Synchronous Generator under Unbalanced Steady State Operation: A Case of Virtual Generator Laboratory." International Journal of Electrical and Computer Engineering (IJECE) 5, no. 6 (December 1, 2015): 1292. http://dx.doi.org/10.11591/ijece.v5i6.pp1292-1303.
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The purpose of this study is to design and develop a synchronous generator virtual laboratory for undergraduate student courses, which can be treated as an accessorial tool for enhancing instruction. Firstly, the study reviews the general concept and algorithm of synchronous generator model. Secondly, the simulation method of this system is discussed. Finally, the paper introduces its example and analysis. One of the major objectives of this project is the dynamics of synchronous generators connected to the 500 kV EHV Jamali (Jawa-Madura-Bali) System under unbalanced steady state condition that could be modeled as a balanced synchronous generator’s model with unbalanced voltage inputs. The balanced synchronous generator model based on the rotor’s qd0 reference frame was chosen to substitute generator’s model embeded in loadflow analysis. The verification of the proposed generator’s model was checked by comparing it with a PSS Tecquiment NE9070 simulator. The unbalanced voltage inputs of generator were derived utilizing the loadflow analysis by determining the phase and sequence currents, and average bus voltages of the 500 kV EHV Jamali grid considering unbalanced portion variations. Meanwhile, the load locations having significant effect on the test generators are obtained by using the electricity tracing method. The developed virtual laboratory with a given example demonstrated the usefulness of the tool for studying synchronous generator under unbalanced steady-state operation.
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KIPPS, JAMES R. "ADVANCED PARSER-GENERATION TECHNOLOGY FOR AI LANGUAGE APPLICATIONS." International Journal on Artificial Intelligence Tools 01, no. 04 (December 1992): 545–61. http://dx.doi.org/10.1142/s0218213092000053.
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A side effect of AI research is the development of programming languages as vehicles for experimentation and demonstration of concepts. These AI languages generally require some form of parser front end, which can be nontrivial to build. Parser generators can ease the task of language development, but commonly available generators use parsing technologies that severely constrain the level of syntactic sophistication, such as allowing at most one symbol of look ahead. Further, these generators are most often targeted for C and Ada applications; parser generators for LISP applications are not widely available. The RAND Advanced Compiler Kit (RACK) is a parser generator for generalized LR parsing and is suitable for AI applications. RACK parsers are unique in their ability to recognize non-LR(k) languages, as well as LR(k) languages for k > 1. RACK is implemented in C and is upwardly compatible with YACC, a widely used parser generator for C applications. RACK generates parsers that interface with C or Common Lisp. RACK also includes features such as arbitrary look-ahead, multiple start symbols, a scanner generator, and a grammar interpreter. In this paper, I describe RACK, its parsing technology, and significant features; I also report performance results comparing RACK to YACC.
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Samraj, Dhas Bensam, and Maruthu Pandi Perumal. "Compatibility of electrical generators for harvesting extended power from wind energy conversion system." Measurement and Control 52, no. 9-10 (August 7, 2019): 1240–51. http://dx.doi.org/10.1177/0020294019858183.
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In this paper, a comparative study between the two generator types with wind energy conversion system is proposed. The two generator types are doubly fed induction generators and permanent magnet synchronous generators. As in the wind turbine context, doubly fed induction generators and permanent magnet synchronous generators seem to be attractive solutions to be used to harness the wind energy. Wind turbine generators compatibility is anticipated in view of the stochastic nature of wind profile in the particular location in correlation with the Electro-Magnetic Torque profile of the wind generator which is acquired by simulating wind energy conversion system for the available wind speeds with high efficient generators. To validate the advantage of the proposed system, the torque profile of doubly fed induction generators and permanent magnet synchronous generators with an hourly average wind speed for 24-h time period is analysed. The real and reactive power of permanent magnet synchronous generators at wind speed of 13 m/s and permanent magnet synchronous generators increased pole pairs at wind speed of 13 m/s are also analysed. Furthermore, the power delivered by doubly fed induction generators and permanent magnet synchronous generators is analysed and compared. The comparison results demonstrate that the superiority of the permanent magnet synchronous generators over doubly fed induction generators and confirm its potential to extract the maximum energy from the wind.
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TANAKA, Kenji, Kiyonori KOGA, Hiroshi SAKO, Sachio TOMITA, and Susumu MAEDA. "E214 TREND IN LARGE HYDROGEN-COOLED TURBINE GENERATORS : THE LATEST TECHONOLOGIES FOR LARGE INDIRECTLY HYDROGEN-COOLED TURBINE GENERATORS(Generator)." Proceedings of the International Conference on Power Engineering (ICOPE) 2009.2 (2009): _2–431_—_2–434_. http://dx.doi.org/10.1299/jsmeicope.2009.2._2-431_.
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Wang, Yongjie, Huizhen Wang, Weifeng Liu, Qin Wang, and Xing Zhao. "Design Method for Variable Frequency Brushless Synchronous Generators." Energies 15, no. 8 (April 11, 2022): 2786. http://dx.doi.org/10.3390/en15082786.
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Brushless synchronous generators, which have the structure of three-stage generators to realize brushless excitation, are the most commonly used aero-generators. With the development of more electric aircraft technology, the output frequency of aero-generators is changing from constant to variable, and the characteristics of generators are also changed. To make sure that the generators can be adapted to the variable frequency operation, this paper analyzes the effects of different operating conditions on generator performance and proposes corresponding design methods. The design and verification of the electromagnetic field, fluid field, temperature field and stress field are carried out for the variable frequency generator. A prototype generator is manufactured according to the design results. An experimental platform is set up to test the performances of the designed generator. The final experimental results show that the generator can work well in variable frequency generation systems, which proves the design method proposed in this paper is effective and feasible.
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Yang, Wen Zhi, Hua Li, and Wen Jun Chen. "Running State Study on Wind-Driven Generator Gearbox." Advanced Materials Research 724-725 (August 2013): 610–13. http://dx.doi.org/10.4028/www.scientific.net/amr.724-725.610.
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Actual survey the vibration data of domestically produced megawatt level wind-driven generator gearbox at different rotational speeds, Extract the parameters of time-domain characteristic, analyze the three dimensional frequency spectrum through the MATLAB software, contrast two same model, same specification wind-driven generator's vibration situation, identify the resonance area of wind-driven generator, and determine the existence of one of the generators shaft misalignment fault. Provide a reliable basis for the safe operation of wind-driven generator.
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Wawrzyński, Wojciech, Mariusz Zieja, Justyna Tomaszewska, and Mariusz Michalski. "Reliability Assessment of Aircraft Commutators." Energies 14, no. 21 (November 6, 2021): 7404. http://dx.doi.org/10.3390/en14217404.
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The article describes the method of predicting the reliability and durability of an aircraft commutator, which is a primary source of electric energy in helicopters. Tests were conducted for 10 starter-generators. From this research it follows that the technical condition of brushes and bearings has a significant impact on the reliability of starter-generators. The reliability of starter-generators was determined based on the method consisting of two stages that was adopted: the first stage involved determining the density function of changes in diagnostic parameter depending on the operating time, but the second stage included the assessment of the reliability of bearings of the starter-generator taking into account the real flight profile. The first stage of the adopted method consisted of defining the dynamic model of changing the length of the starter-generator’s brush, which became the probabilistic model. Subsequently, based on differential equations, Fokker–Planck partial differential equation was derived, which describes the process of increasing the brush wear in a probabilistic way. This method enables the prediction of the residual durability of the helicopter’s starter-generator due to the change in a diagnostic parameter which is the wear of brushes during starter-generator operation. The second stage of this method allows determining the durability of starter-generator’s bearings building upon the average helicopter’s flight profile. Owing to the difficulty in measuring the wear of bearings, the relation between the durability of bearings and the temperature of surroundings can be applied by replacing the flight altitude with temperature. The reliability of the helicopter’s starter-generator was determined based on the serial-type reliability structure.
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Iokova, I. L., and E. N. Tarasevich. "INVESTIGATION OF THE POSSIBILITY OF USING A VORTEX HEAT GENERATOR IN HEAT SUPPLY SYSTEMS FOR RESIDENTIAL, INDUSTRIAL AND PUBLIC BUILDINGS." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 61, no. 2 (April 5, 2018): 159–66. http://dx.doi.org/10.21122/1029-7448-2018-61-2-159-166.
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In a number of foreign countries, vortex heat generators have become widespread in decentralized heat supply systems. For Belarus, vortex heat generators are quite new sources of heat supply. The article considers the possibility of using vortex heat generators for heat supply systems for residential, public and industrial buildings. Vortex heat generators are based on the principle of cavitation in a turbulent water flow. For many devices cavitation is not desirable, but in a vortex heat generator it is used as a favorable phenomenon. The authors carried out a series of full-scale experiments to determine the efficiency of the “VTG-2.2” vortex heat generator when different operating modes were applied. The performance of the vortex heat generator can be estimated by the energy conversion factor. Energy conversion factor is the ratio of the amount of thermal energy that a vortex heat generator generates to the amount of electrical energy consumed. Experiments conducted in a number of research organizations (including the National Academy of Sciences of Ukraine and MPEI) have demonstrated that energy conversion factor can exceed 1. The authors conducted experimental tests with the use of an experimental installation simulating a heat supply system. According to the obtained experimental data, the energy conversion coefficients for each mode were calculated. The constructed graphical dependencies clearly demonstrate that, with increasing rotational speed of the vortex heat generator, the efficiency of its use increases. The highest energy conversion factor value was 61.1 % with a rotation frequency of 40 Hz. It was also found that with increasing the rotational speed of the vortex heat generator, a significant increase in noise and vibration occurs.
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Menzhinski, A. B., A. N. Malashin, and Yu V. Suhodolov. "DEVELOPING AND THE ANALYSIS OF MATHEMATICAL MODELS OF GENERATORS OF LINEAR AND RECIPROCATING TYPES WITH ELECTROMAGNETIC EXCITATION." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 61, no. 2 (April 5, 2018): 118–28. http://dx.doi.org/10.21122/1029-7448-2018-61-2-118-128.
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The mathematical modeling of generators of linear and reciprocating types with electromagnetic excitation resulted in obtaining the equivalent electrical circuit and diagrams of magnetic circuit of generators as well as the expressions that describe the electromagnetic processes in generators of linear and reciprocating types with electromagnetic excitation is presented in the article. Mathematical models of generators of linear and reciprocating types with electromagnetic excitation take into account the geometrical parameters of the magnetic system of generators, effect of the armature reaction, the unequal distribution of the magnetic field in the magnetic system of the generators and the dependence of the scattering coefficient and the fringe effect (in linear generators) and buckling (in the reciprocating electric generators) on the coordinates of the movement. An evaluation of the effectiveness of the generators of linear and reciprocating types with electromagnetic excitation was performed that demonstrated that the efficiency of the reciprocating generator with electromagnetic excitation is limited to the amount of movement of the moving part of the generator that can be considered as a drawback of this type of generators. Therefore, the reciprocating generator with electromagnetic excitation is more effective to be used in a small value of the working stroke of the movable part of it or in conjunction with a linear generator as a compensator of the end effect in reciprocating motion. In the linear generator the rate of change of inductance and mutual inductance throughout the movement of the moving part is practically constant. So if an increase of the magnitude of the working stroke of the movable part takes place the benefits of the linear generator are undeniable. However, it should be noted that a reduction of the stroke magnitude of the movable part of the linear generator is limited by constructional dimensions of the magnetic system of the generator, which reduces its efficiency at low value of the working stroke of the movable part.
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Cardell, Sara D., Amparo Fúster-Sabater, and Adrián H. Ranea. "Linearity in decimation-based generators: an improved cryptanalysis on the shrinking generator." Open Mathematics 16, no. 1 (June 14, 2018): 646–55. http://dx.doi.org/10.1515/math-2018-0058.
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AbstractDecimation-based sequence generators are a class of non-linear cryptographic generators designed to be used in hardware implementations. An inherent characteristic of such generators is that their output sequences are interleaved sequences. This profitable characteristic can be used in the cryptanalysis of those generators. In this work, emphasis is on the most representative decimation-based generator, the shrinking generator, which has been cryptanalyzed just by solving linear equation systems. Compared with previous cryptanalysis, computational complexity and intercepted sequence requirements are dramatically reduced. Although irregularly decimated generators have been conceived and designed as non-linear sequence generators, in practice they can be easily analyzed in terms of simple linear structures.
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BALBES, RAYMOND. "FREE TERNARY ALGEBRAS." International Journal of Algebra and Computation 10, no. 06 (December 2000): 739–49. http://dx.doi.org/10.1142/s0218196700000340.
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A ternary algebra is a bounded distributive lattice with additonal operations e and ~ that satisfies (a+b)~=a~b~, a~~=a, e≤a+a~, e~= e and 0~=1. This article characterizes free ternary algebras by giving necessary and sufficient conditions on a set X of free generators of a ternary algebra L, so that X freely generates L. With this characterization, the free ternary algebra on one free generator is displayed. The poset of join irreducibles of finitely generated free ternary algebras is characterized. The uniqueness of the set of free generators and their pseudocomplements is also established.
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Faiz, Jawad, Tohid Asefi, and Mohammad Khan. "Design of dual rotor axial flux permanent magnet generators with ferrite and rare-earth magnets." Facta universitatis - series: Electronics and Energetics 33, no. 4 (2020): 553–69. http://dx.doi.org/10.2298/fuee2004553f.
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This article addresses dual rotor axial flux Ferrite permanent magnet (PM) generator, as an alternative to a surface mounted and spoke types Nd-Fe-B generator which have concentrated windings. The performance parameters of all generators, particularly the efficiency, are identical. The design objective function is the generators mass minimization using a population-based algorithm. To predict the performance of the generators a finite element (FE) technique is applied. Besides, the aims of the design include minimizing cogging torque, examining different rotor pole topologies and different pole arc to pole pitch ratios. Three-dimensional FE technique is employed. It is shown that the surface mounted Ferrite generator topology cannot develop the rated torque and also has high torque ripple. In addition, it is heavier than the spoke type generator. Furthermore, it is indicated that the spoke type Ferrite PM generator has favorable performance and could be an alternative to rare-earth PM generators, particularly in wind energy applications. Finally, the performance of the designed generators is experimentally verified.
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Xu, Yuanyuan, Lian-Tong An, Xiao-Ping Jia, Bao-Zhu Jia, and Naoki Maki. "Optimization study of the main parameters of different types of wind turbine generators *." Superconductor Science and Technology 35, no. 3 (February 4, 2022): 035007. http://dx.doi.org/10.1088/1361-6668/ac4f3e.
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Abstract The research and development of large-scale wind turbine generators have become a future trend in green renewable energy field from the dual perspectives of the environment and economics. In this work, an electrical design method is first proposed and applied to different types of wind turbine generators, including the high-temperature superconducting (HTS), the permanent magnet, and the traditional copper generators. The optimal electrical designs of the three types of 10 MW wind turbine generators are then created based on the developed design program. Second, the influences of the rated revolution on the basic performance parameters of the HTS generator are investigated, and the results are compared with those of the other two types of generators. It is found that the generator weight decreases with the increases of the rated revolution and the stator outer diameter, and the optimal rated revolution for a generator with a large stator outer diameter is determined to be 40 min−1. Moreover, the weight of the field parts is found to have the same regulation rule as the generator weight. Finally, the design results of the three types of wind turbine generators are comparatively discussed, and it is found that the HTS wind turbine generator is superior to its two counterparts.
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Liu, Zhi Jian, Rong Huang, Shu Ming Zhou, and Qi Song. "Application of Coherency Property of Generator to Analysis of Low-Frequency Oscillation in Power System." Advanced Materials Research 827 (October 2013): 136–41. http://dx.doi.org/10.4028/www.scientific.net/amr.827.136.
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Coherency is used to characterize the degree of confusion between generators which oscillate against each other, so it can judge the process which generators oscillate from local mode to inter-area mode. The coherency is the value of the direction cosine by using angle of the generators. when the direction cosines of two generator is 1 that indicates the oscillation direction between the two generators is inter-area oscillation mode; when the direction cosines of two generator is-1 that indicates the oscillation direction between the two generators is local oscillation mode. Coherency is affected by speed governing system and excitation system of generator.Using two area systems verifies the theoretical analysis is correct.
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Riyadi, Eko, Tri Priyambodo, and Agfianto Putra. "The Dynamic Symmetric Four-Key-Generators System for Securing Data Transmission in the Industrial Control System." International Journal of Intelligent Engineering and Systems 14, no. 1 (February 28, 2021): 376–86. http://dx.doi.org/10.22266/ijies2021.0228.35.
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Most of the communication protocols in the Industrial Control System (ICS) are vulnerable to cyber-attacks. Initially, the network protocol was designed for reliable performance, and thus did not incorporate data transmission security features. Therefore, ICS requires adequate data transmission security. This paper suggests improving the security of data transmission through a dynamic symmetric four-key-generators system, wherein the system anticipates cyberattacks by generating four keys before encryption. It involves four generators: a random initial key generator, a keystream generator, a key scheduling algorithm generator, and a pseudo-random number algorithm generator. In the receiver section, the system generates three keys before decryption to ensure data confidentiality and to avoid cyberattacks. The test results show that the proposed system keyspace is ≈22048 bits, meaning that the key is more secure from brute force attacks. As a result, the cipher data have a correlation value of 0.00007. The entropy value is 7.99, indicating that the cipher data is more secure. Also, speed tests show that the processing time still qualifies as realtime.
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Brecher, Christian, Stephan Neus, Marcus Gärtner, Hans-Martin Eckel, Maik Hoppert, Barry James, Chris Gerada, Michele Degano, Mohammad Reza Ilkhani, and Mauro Di Nardo. "Design of an aircraft generator with radial force control." Open Research Europe 2 (September 29, 2022): 73. http://dx.doi.org/10.12688/openreseurope.14684.2.
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With the increasing electrical energy demands in aviation propulsion systems, the increase in the onboard generators’ power density is inevitable. During the flight, forces coming from the gearbox or gyroscopic forces generated by flight manoeuvres like take-off and landing can act on the generators' bearings, which can lead to wear and fatigue in the bearings. Utilizing the radial force control concept in the electrical machine can relieve loads from the bearings that not only minimize the bearing losses but also increase bearing life. The objective of the MAGLEV project (Measurement and Analysis of Generator bearing Loads and Efficiency with Validation) is to study, demonstrate, and test a new class of high-speed generators with radial force control. In this paper, design steps of this type of generator and its test rig are presented and the measurement methodology used for radial force control is explained. The concept is developed in an electrical machine and is validated on a test rig by measuring required parameters like shaft displacement, vibrations and bearing temperature. Additionally, the friction moment of each generator’s bearings is measured and validated in a separate test rig under comparable conditions to the bearing loads in the generator. Therefore, a novel approach to determine precisely the bearing friction in a radial load unit, rotatably supported by an additional needle bearing is used, which shows a good agreement with the calculated friction. Furthermore, new calculation methods for the operating behavior of cylindrical roller bearings with clearance are presented, which are utilized in the generator test rig.
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Brecher, Christian, Stephan Neus, Marcus Gärtner, Hans-Martin Eckel, Maik Hoppert, Barry James, Chris Gerada, Michele Degano, Mohammad Reza Ilkhani, and Mauro Di Nardo. "Design of an aircraft generator with radial force control." Open Research Europe 2 (June 6, 2022): 73. http://dx.doi.org/10.12688/openreseurope.14684.1.
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With the increasing electrical energy demands in aviation propulsion systems, the increase in the onboard generators’ power density is inevitable. During the flight, forces coming from the gearbox or gyroscopic forces generated by flight manoeuvres like take-off and landing can act on the generators' bearings, which can lead to wear and fatigue in the bearings. Utilizing the radial force control concept in the electrical machine can relieve loads from the bearings that not only minimize the bearing losses but also increase bearing life. The objective of the MAGLEV project (Measurement and Analysis of Generator bearing Loads and Efficiency with Validation) is to study, demonstrate, and test a new class of high-speed generators with radial force control. In this paper, design steps of this type of generator and its test rig are presented and the measurement methodology used for radial force control is explained. The concept is developed in an electrical machine and is validated on a test rig by measuring required parameters like shaft displacement, vibrations and bearing temperature. Additionally, the friction moment of each generator’s bearings is measured and validated in a separate test rig under comparable conditions to the bearing loads in the generator. Therefore, a novel approach to determine precisely the bearing friction in a radial load unit, rotatably supported by an additional needle bearing is used, which shows a good agreement with the calculated friction. Furthermore, new calculation methods for the operating behavior of cylindrical roller bearings with clearance are presented, which are utilized in the generator test rig.
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Adrianti, Adrianti, Syndy Maiyunis Firdaus, and Muhammad Nasir. "The Effect of Wind Power Generation on Distance Relay Performance." Andalas Journal of Electrical and Electronic Engineering Technology 2, no. 1 (June 16, 2022): 1–6. http://dx.doi.org/10.25077/ajeeet.v2i1.17.
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Wind Power Plants utilize induction generators to generate electrical power. This type of generator produces less short circuit current than synchronous generators; hence it may affect the operation of transmission line protection relays. This research aims to analyze the effect of a large-scale wind power plant connected to the transmission line on the performance of the distance relays. The study utilizes a simulation method using Digsilent Powerfactory on IEEE 5 bus test system. The performance of the distance relays is compared between the original system, and the system in one of its generators is replaced with a wind turbine generator. The simulations are carried out for 3-phase faults that consist of bolted short circuits, 1-ohm fault resistance and 10-ohm fault resistances. The results show that the relays performances in zone 1 are the same for all types of generations. For zones 2 and 3, depending on the relay's position, the reaches may increase or decrease when the generator is replaced by wind power. The increasing reach of the relays is due to the dropping of infeed effect felt by the relay after installation of wind power. While the decreasing reaches of some relays because they see less fault current from the wind generation. The other relays do not experience any changes. Fault resistances cause all relays to experience reduced reach.
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Korchynskyi, Volodymyr, Vitalii Kildishev, Oleksandr Riabukha, and Oleksandr Berdnikov. "THE GENERATING RANDOM SEQUENCES WITH THE INCREASED CRYPTOGRAPHIC STRENGTH." Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska 10, no. 1 (March 30, 2020): 20–23. http://dx.doi.org/10.35784/iapgos.916.
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Random sequences are used in various applications in construction of cryptographic systems or formations of noise-type signals. For these tasks there is used the program generator of random sequences which is the determined device. Such a generator, as a rule, has special requirements concerning the quality of the numbers formation sequence. In cryptographic systems, the most often used are linearly – congruent generators, the main disadvantage of which is the short period of formation of pseudo-random number sequences. For this reason, in the article there is proposed the use of chaos generators as the period of the formed selection in this case depends on the size of digit net of the used computing system. It is obvious that the quality of the chaos generator has to be estimated through a system of the NIST tests. Therefore, detailed assessment of their statistical characteristics is necessary for practical application of chaos generators in cryptographic systems. In the article there are considered various generators and there is also given the qualitative assessment of the formation based on the binary random sequence. Considered are also the features of testing random number generators using the system. It is determined that not all chaos generators meet the requirements of the NIST tests. The article proposed the methods for improving statistical properties of chaos generators. The method of comparative analysis of random number generators based on NIST statistical tests is proposed, which allows to select generators with the best statistical properties. Proposed are also methods for improving the statistical characteristics of binary sequences, which are formed on the basis of various chaos generators.
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KANTOROVITZ, SHMUEL. "GENERATORS OF REGULAR SEMIGROUPS." Glasgow Mathematical Journal 50, no. 1 (January 2008): 47–53. http://dx.doi.org/10.1017/s0017089507003916.
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AbstractA regular semigroup (cf. [4, p. 38]) is a C0-semigroup T(⋅) that has an extension as a holomorphic semigroup W(⋅) in the right halfplane $\Bbb C^+$, such that ||W(⋅)|| is bounded in the ‘unit rectangle’ Q:=(0, 1]× [−1, 1]. The important basic facts about a regular semigroup T(⋅) are: (i) it possesses a boundary groupU(⋅), defined as the limit lims → 0+W(s+i⋅) in the strong operator topology; (ii) U(⋅) is a C0-group, whose generator is iA, where A denotes the generator of T(⋅); and (iii) W(s+it)=T(s)U(t) for all s+it ∈$\Bbb C^+$ (cf. Theorems 17.9.1 and 17.9.2 in [3]). The following converse theorem is proved here. Let A be the generator of a C0-semigroup T(⋅). If iA generates a C0-group, U(⋅), then T(⋅) is a regular semigroup, and its holomorphic extension is given by (iii). This result is related to (but not included in) known results of Engel (cf. Theorem II.4.6 in [2]), Liu [7] and the author [6] for holomorphic extensions into arbitrary sectors, of C0-semigroups that are bounded in every proper subsector. The method of proof is also different from the method used in these references. Criteria for generators of regular semigroups follow as easy corollaries.
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Oktaviani, Wiwin A., Taufik Barlian, and Yosi Apriani. "Studi Awal Karakteristik Tegangan Ouput Generator Magnet Permanen dan Generator DC pada Turbin Kubah Masjid Putar." Electrician 14, no. 2 (May 15, 2020): 56–63. http://dx.doi.org/10.23960/elc.v14n2.2149.
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Intisari — Setiap yang berputar memiliki potensi energi kinetik, tidak terkecuali putaran kubah masjid. Penelitian ini bertujuan untuk mengetahui potensi pemanfaatan kubah putar masjid sebagai penghasil energi listrik skala kecil. Generator yang diuji cobakan adalah generator magnet permanen dan generator DC yang dirangkaikan dengan turbin kubah putar. Pengujian dilakukan di dua lokasi, di Jembatan Musi 2 Palembang dan di perairan Sungsang Kabupaten Banyuasin untuk mengukur besaran tegangan dan arus output yang dihasilkan pada berbagai kecepatan angin menggunakan multimeter dan anemometer. Hasil penelitian menunjukkan bahwa tegangan yang dihasilkan oleh putaran kubah masjid menggunakan generator magnet permanen mampu mencapai 14,21 V pada kecepatan angin 3,8 m/det dibandingkan dengan generator DC yang hanya mencapai 3 V pada kecepatan angin 8 m/det. Jika ditinjau dari besaran arus, generator magnet permanen menghasilkan arus konstan sebesar 0,3 A sedangkan pada generator DC arus yang dihasilkan tidak terukur karena nilainya yang amat kecil. Penelitian ini menunjukkan bahwa kubah putar masjid dapat dijadikan sebagai turbin angin pada daerah yang memiliki kecepatan angin rendah.
Kata kunci — kubah masjid putar,generator magnet permanen,generatorDC, turbin angin kecepatan rendah
Abstract - Every spinning has kinetic energy potential; the mosque dome is no exception. This study aims to determine the potential use of the mosque's turning dome as a producer of small-scale electrical energy. Two types of the generator were tested, which were permanent magnet generator and DC generator, which were coupled with a rotary dome turbine. The test was carried out at two locations, at Palembang Musi 2 Bridge and in the waters of Sungsang, Banyuasin Regency, to measure the amount of voltage and output current generated at various wind speeds using a multimeter and anemometer. The results showed that the voltage generated by the mosque's dome rotation using a permanent magnet generator was able to reach 14.21 V at wind speeds of 3.8 m / sec compared to DC generators, which only reached 3 V at 8 m / s wind speed. When viewed from the amount of current, permanent magnet generators produce a constant current of 0.3 A while in DC generators, the current generated is not measurable because the value is minimal. This research shows that the mosque's rotary dome can be used as a wind turbine in areas that have low wind speeds.
Keywords - rotary mosque domes, permanent magnet generators, generator DC, low speed wind turbines
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Niu, Yitong, Intisar A. M. Al Sayed, Alya'a R. Ali, Israa Al_Barazanchi, Poh Soon JosephNg, Zahraa A. Jaaz, and Hassan Muwafaq Gheni. "Research on fault adaptive fault tolerant control of distributed wind solar hybrid generator." Bulletin of Electrical Engineering and Informatics 12, no. 2 (April 1, 2023): 1029–40. http://dx.doi.org/10.11591/eei.v12i2.4242.
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Due to the poor accessibility, poor operating conditions, high failure rate, long maintenance time, and difficult maintenance of wind hybrid generators, the economic loss is huge once the failure stops. To this end, the fault adaptive fault-tolerant control of distributed wind and wind hybrid generators is studied, the historical operation data of offshore wind and wind hybrid generators and onshore wind and wind hybrid generators are counted and compared, and the fault characteristics of key components of offshore wind and wind hybrid generators are analyzed. The generator sets are summarized, and the common electrical faults of wind turbines and their impacts on the system are analyzed. This paper summarizes the current research status of fault-tolerant operation of existing offshore wind and wind complementary generators in terms of software fault tolerance and hardware fault tolerance, summarizes the current fault tolerance schemes for offshore wind and wind complementary generators, and analyzes the application feasibility of existing fault tolerance schemes. In addition, the main problems of fault-tolerant offshore wind and solar complementary generator sets are pointed out, and future research hotspots are foreseen.
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Tarnapowicz, Dariusz, Sergey German-Galkin, and Marek Staude. "Investigation Concerning the Excitation Loss of Synchronous Generators in a Stand-Alone Ship Power Plant." Energies 14, no. 10 (May 14, 2021): 2828. http://dx.doi.org/10.3390/en14102828.
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The protection systems of ship generators enable them to eliminate potential failures that pose a significant threat to the safety of the crew and the use of the ship. However, due to the fact that marine classification societies do not require the protection of generators against the loss of excitation, such protection is only used sporadically. This article presents an LOE (loss of excitation) analysis of ship generators that operate in parallel. This analysis is supported by simulations and experimental research. The test results show that the positions of the operating points of each generator are interrelated, and changes in the excitation of one (damaged) generator cause automatic changes in the excitation, as well as changes in electromagnetic and energy processes, in the second (efficient) generator. An LOE in one generator causes a dangerous increase in armature currents in both generators. The results of this study prove that the lack of LOE protection at lower levels of excitement in one of the generators causes (by activating the required protection) the efficient generator to be switched off first. The main conclusion of this article is that the introduction of the use of security measures against LOE should be obligatory and legally required.
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Yefimov, Olexander, Larysa Tiutiunyk, Tetyana Harkusha, Tetyana Yesipenko, and Anastasiia Motovilnik. "Mathematical model of the horizontal steam generator PGV-1000." NTU "KhPI" Bulletin: Power and heat engineering processes and equipment, no. 1-2 (December 28, 2022): 53–57. http://dx.doi.org/10.20998/2078-774x.2022.01.06.
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The materials of the article consider the design characteristics of horizontal steam generators PGV-1000 for WWER NPPs. The NPP steam generator, in particular the PGV-1000 steam generator, is a specific heat exchange unit. This unit, together with a nuclear reactor and a steam turbine, is one of the main equipment of multi-circuit (double-circuit) steam turbine NPPs. The steam generator produces working steam using heat dissipated from the reactor core by the cooling medium and sent to the heat exchange surface of the steam generator. NPP steam generators, connecting the contours of the coolant and the working substance, equally belong to each of them. The heat-absorbing medium in the steam generator is the working substance (water, steam). PGV-1000 type NPP steam generators with pressurized water reactors produce dry saturated steam. The requirement to maintain high purity of the coolant is due to the heat transfer surfaces of such steam generators made of austenitic stainless steel with electropolished surfaces. The design characteristics of modern horizontal steam generators such as PGV-1000 of various modifications provide high technical and economic performance of NPP units with WWER-1000 and high maintainability, which allows to extend the service life of domestic NPPs.
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Metwally, M. M., M. K. Ratib, M. M. Aly, and A. M. Abdel‑Rahim. "Effect of Grid Faults on Dominant Wind Generators for Electric Power System Integration:A Comparison and Assessment." Energy Systems Research, no. 3(15) (November 30, 2021): 70–78. http://dx.doi.org/10.38028/esr.2021.03.0007.
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In recent times, various types of wind generators have been linked to the power grids globally and the focus has been to control them to be more efficient and reliable. This study concisely discusses performance analysis, modeling, and assessment of different wind generators (permanent magnet synchronous generator, doubly-fed induction generator, squirrel cage induction generator), covering their benefits, drawbacks, and impact on the electric power systems. This comparison aims to guarantee that their technical and economic evaluations are comparable, allowing engineers to make a more informed decision about which generator is best suitable for their installation. Findings for the investigated wind generators lead to significant observations about their application fields, such as permanent magnet synchronous generator outperforms doubly-fed induction generator and squirrel cage induction generator, especially during grid disruptions; on the other hand, squirrel cage induction generator is simple and inexpensive.
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Hyvernaud, Jeremy, Gwenael Reineix, Romain Negrier, Joel Andrieu, Michele Lalande, and Vincent Couderc. "Optoelectronic generation of transient waveforms for UWB radars with rejected frequencies." International Journal of Microwave and Wireless Technologies 12, no. 7 (April 7, 2020): 543–50. http://dx.doi.org/10.1017/s1759078720000288.
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AbstractIn this paper, a new design of an optoelectronic system for transient waveforms shaping, with a selection of rejected frequencies, is presented. The generation of short pulses is performed with several optoelectronic generators using photoconductive semiconductor switches (PCSS) operating in linear switching mode and triggered via a laser pulse. With the appropriate number of generators, the system generates a spectrum ranging from 300 MHz to 3 GHz, with rejected frequencies at 900 MHz and 1.8 GHz. A PCSS characterization has been set up to determine the necessary parameters for the establishment of an optoelectronic generator model on Keysight Advanced Design System software (ADS). Experimental tests have been realized using measurement benches to compare the simulated and measured signals.
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GUEDES, ELLOÁ B., F. M. DE ASSIS, and BERNARDO LULA. "Quantum attacks on pseudorandom generators." Mathematical Structures in Computer Science 23, no. 3 (December 20, 2012): 608–34. http://dx.doi.org/10.1017/s0960129512000825.
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There are advantages in the use of quantum computing in the elaboration of attacks on certain pseudorandom generators when compared with analogous attacks using classical computing. This paper presents a polynomial time quantum attack on the Blum–Micali generator, which is considered secure against threats from classical computers. The proposed attack uses a Grover inspired procedure together with the quantum discrete logarithm, and is able to recover previous and future outputs of the generator under attack, thereby completely compromising its unpredictability. The attack can also be adapted to other generators, such as Blum–Micali generators with multiple hard-core predicates and generators from the Blum–Micali construction, and also to scenarios where the requirements on the bits are relaxed. Such attacks represent a threat to the security of the pseudorandom generators adopted in many real-world cryptosystems.
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Zhang, Zhaohuang, and Weiwei Li. "Calculation of the Strength of Vortex Currents Induced by Vortex Generators on Flat Plates and the Evaluation of Their Performance." Energies 15, no. 7 (March 26, 2022): 2442. http://dx.doi.org/10.3390/en15072442.
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Vortex generators are used to overturn the momentum of the flow in the boundary layer, thereby preventing flow separation, and are broadly used in aviation, wind power, heat exchange, and different fields. It has been determined that the capability of an eddy current generator to manipulate the boundary layer is proportional to the intensity of the vortex strength it excites. Although the mathematical notion of vortex strength is very well defined, there are difficulties in figuring out vortex strength in applications. This article proposes a calculation method based on confidence intervals and contour eddy current intensity. Meanwhile, the contemporary overall performance evaluation of vortex generators is frequently obtained in a roundabout way through their consequences on feature factors (e.g., lift coefficients, etc.), and techniques for the direct assessment of a vortex generator’s overall performance are no longer available. To address this situation, the article derives the performance evaluation criterion of the equal height vortex generators, the harmonic intensity factor (K=ωpeak r′), based on the Biot–Savart theorem.
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Airoboman, A. E., Mohammed A. S. Jibrin, J. O. Ademola, J. Oladokun, S. Ahmed, and M. O. Edu. "Efficiency Analysis on Small Sized Generators in Nigeria." Journal of Advances in Science and Engineering 2, no. 2 (December 31, 2019): 37–44. http://dx.doi.org/10.37121/jase.v2i2.66.
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In this paper, efficiency analysis of small sized generators in Nigeria was considered. Experimental analyses were carried out on two (2) different samples of generators tagged “S” and “T” at different loading conditions (20%, 40%, 60% etc. of ratings) to ascertain the generators’ efficiencies as well as the maximum true power that could be drawn out from the generators. The experimental results are compared with the manufacturers ratings specified on the name plate of the generators. The results indicated an average efficiency of 44.9% and 55.7% for “T” and “S” respectively an indication that generator “S” is more efficient that “T”. The results also showed that the values of the power factor indicated on the generators are inaccurate as none of the generators could give the maximum power as indicated on their name plates based on the experimental analysis carried out. The generators selected were able to provide adequate power to the selected loads with efficiencies not up to 100% of the expected rated value of the generators. For generator “S” it was observed that the efficiency decreases from the highest rating to the lowest rating. Conclusively, this result suggests that portable generators dealers are taking advantage of the energy crises to importing generators not up to specifications to the Nigerian market at the expense of naïve customers. This paper recommends that proper standards and measures be put in place and enforced by the relevant authority for conformity of standards to all imported generators to save guard and protect the interest of potential customers and Nigerians.
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Goldstein, Harrison, and Benjamin C. Pierce. "Parsing randomness." Proceedings of the ACM on Programming Languages 6, OOPSLA2 (October 31, 2022): 89–113. http://dx.doi.org/10.1145/3563291.
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Random data generators can be thought of as parsers of streams of randomness. This perspective on generators for random data structures is established folklore in the programming languages community, but it has never been formalized, nor have its consequences been deeply explored. We build on the idea of freer monads to develop free generators, which unify parsing and generation using a common structure that makes the relationship between the two concepts precise. Free generators lead naturally to a proof that a monadic generator can be factored into a parser plus a distribution over choice sequences. Free generators also support a notion of derivative, analogous to the familiar Brzozowski derivatives of formal languages, allowing analysis tools to "preview" the effect of a particular generator choice. This gives rise to a novel algorithm for generating data structures satisfying user-specified preconditions.
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Chen, Lei, Zuoxia Xing, Bowen Zhu, Dongrui Wang, Yuzhang Gao, and Xiaoqi Wang. "Research on cogging torque optimization design of permanent magnet synchronous wind turbine." E3S Web of Conferences 300 (2021): 01001. http://dx.doi.org/10.1051/e3sconf/202130001001.
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Cogging torque is one of the unique problems of permanent magnet generators. Its main cause is the uneven distribution of the generator’s magnetic permeability, which directly affects the starting and running performance of the generator. The study of cogging torque suppression methods is of great significance for improving the operating stability and service life of generators. Through the analysis of the principle of cogging torque, an optimization method for the amplitude of cogging torque based on Taguchi algorithm for the two parameters of pole arc coefficient and skew angle is established. And the finite element analysis method is used to quantitatively compare the characteristic parameters of the generator model before and after the optimization by Taguchi algorithm. The results show that when the pole arc coefficient and the angle of the chute are in the optimal value at the same time, the cogging torque of the generator can be greatly reduced, and its air gap magnetic density waveform and induced electromotive force waveform are ideal, which provides a research method for the design and parameter optimization of large megawatt permanent magnet synchronous wind turbines.
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Eriksson, Sandra. "Inherent Difference in Saliency for Generators with Different PM Materials." Journal of Renewable Energy 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/567896.
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The inherent differences between salient and nonsalient electrical machines are evaluated for two permanent magnet generators with different configurations. The neodymium based (NdFeB) permanent magnets (PMs) in a generator are substituted with ferrite magnets and the characteristics of the NdFeB generator and the ferrite generator are compared through FEM simulations. The NdFeB generator is a nonsalient generator, whereas the ferrite machine is a salient-pole generator, with small saliency. The two generators have almost identical properties at rated load operation. However, at overload the behaviour differs between the two generators. The salient-pole, ferrite generator has lower maximum torque than the NdFeB generator and a larger voltage drop at high current. It is concluded that, for applications where overload capability is important, saliency must be considered and the generator design adapted according to the behaviour at overload operation. Furthermore, if the maximum torque is the design criteria, additional PM mass will be required for the salient-pole machine.
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Prabowo, Petrus Setyo, Stefan Mardikus, and Ewaldus Credo Eukharisto. "Heat Transfer Characteristic on Wing Pairs Vortex Generator using 3D Simulation of Computational Fluid Dynamic." International Journal of Applied Sciences and Smart Technologies 3, no. 2 (December 31, 2021): 215–24. http://dx.doi.org/10.24071/ijasst.v3i2.3839.
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Vortex generators are addition surface that can increase heat transfer area and change the fluid flow characteristics of the working fluid to increase heat transfer coefficient. The use of vortex generators produces longitudinal vortices that can increase the heat transfer performance because of the low pressure behind vortex generators. This investigation used delta winglet vortex generator that was combined with rectangular vortex generator to Reynold numbers ranging 6,000 to 10,000. The parameters of Nusselt number, friction factor, velocity vector and temperature distribution will be evaluated.
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Saukon Kamalul Husna, Anif, Desriyanti Desriyanti, and Rhesma Intan Vidyastari. "Air Temperature Control System In Silent Generator Box." JEEE-U (Journal of Electrical and Electronic Engineering-UMSIDA) 5, no. 2 (October 5, 2021): 165–74. http://dx.doi.org/10.21070/jeeeu.v5i2.1556.
Full textAbstract:
For the community, generators are an alternative if there is a power outage or if there is a large enough electricity demand. According to workers in the field of generator rental in Trenggalek, namely "db Genset" which has the address Ds. Gondang, Kec. Tugu, Kab. Trenggalek, there are 2 types of generators, namely open generators and silent generators, and most people choose silent generators because silent generators are specially designed to muffle engine noise so they don't cause noise, very suitable for use in active environments, but silent generators often experience temperature problems rise (Overheating) which is due to a closed engine and less smooth air circulation. Thus the cooling system on the generator set is needed to support the safety of the temperature on the silent generator so that it remains normal below 70°C which is important to minimize overheating problems in the silent generator, so that it can improve the performance of the generator to work for a long time without any problems. overheating. The design of the Temperature Control System in this Silent Genset Box uses Arduino Uno as a system controller and uses the Ds18b20 sensor, the engine temperature cooling process previously relied on radiator water and radiator fans, so the idea arose to add blower fans on both sides of the silent generator box, marked with a green temperature light indicator. being below 70°C indicates the temperature inside the box is normal, the blue light indicator indicates the temperature inside the box is in the 70°C to 95°C temperature range, fan 1 is on, the red light indicator indicates the temperature in the box is in the 95°C to 120°C temperature range, fans 1 and 2 are on, and the red light indicator indicates the temperature in the box is in the temperature range of 95°C to 120°C if the temperature reaches 120°C the generator engine will turn off indicating the temperature in the box maxsimal fan 1 and 2 remain on until the temperature decreases to 40°C, and every change in temperature will send a notification via SMS to the generator operator
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Abramov, Y., V. Kryvtsova, and A. Mikhailyuk. "PHASE METHODS OF GAS GENERATORS CONTROL HYDROGEN STORAGE AND SUPPLY SYSTEMS." Municipal economy of cities 6, no. 166 (November 30, 2021): 146–50. http://dx.doi.org/10.33042/2522-1809-2021-6-166-146-150.
Full textAbstract:
Methods of control of technical condition of gas generators of systems of storage and supply of hydrogen based on use of their phase-frequency characteristics are considered. Methods of control of gas generators are divided into two groups depending on the mathematical models used to describe the operation of such gas generators. It is shown that when using as such a mathematical model the transfer function of the gas generator in the form of an inertial link, it is possible to implement control algorithms both by its phase-frequency characteristics and by its time constant. In the first case, the phase-frequency characteristic is measured at an a priori set frequency. In the second case, there is no such restriction. When using as a mathematical model of the gas generator the transfer function in the form of a fractional-rational function of the second order, the implementation of algorithms for its control can be carried out directly using the phase-frequency characteristics of the gas generator. With this implementation of algorithms for monitoring the technical condition of gas generators, the measurement of the values of their phase-frequency characteristics is carried out at several frequencies. This approach to the control of gas generators can increase the reliability of its results. All methods of monitoring the technical condition of gas generators of hydrogen storage and supply systems are focused on the use of tolerance criteria. The parameters of the tolerance criteria can be both the values of the time constants of gas generators of hydrogen storage and supply systems, and fixed values of the phase-frequency characteristics of such gas generators. In the latter case, control algorithms are implemented that cover the entire operating frequency range of gas generators.
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Bharathi, Manne, Udochukwu Bola Akuru, and Malligunta Kiran Kumar. "Comparative Design and Performance Analysis of 10 kW Rare-Earth and Non-Rare Earth Flux Reversal Wind Generators." Energies 15, no. 2 (January 17, 2022): 636. http://dx.doi.org/10.3390/en15020636.
Full textAbstract:
Generators are a key technological element of the wind energy generation system. Currently, there is an increasing interest in adopting non-conventional stator-mounted permanent magnet generators, e.g., flux reversal generators (FRGs), which is a good alternative to conventional synchronous generators for medium-speed wind turbine generator applications. The usage of FRG with rare-earth (RE) permanent magnets (PMs) is increasing due to their high efficiency and high power density factors. However, RE PMs are unattractive to wind generators in terms of their cost and unpredictable market supply. In this paper, an attempt is made to study the potential of FRG with non-rare earths (ferrite PMs) for wind generators. The three-phase, 6/8 pole FRG is designed and compared with RE and NRE PMs for wind generator application at 375 r/min, 10 kW. Using 2D FEA, both the generators are compared in terms of their power generating performance with excellent overload capability. It shows that the average efficiency of the generators is approximately similar, but the torque density of NRE-FRG is only 51% that of RE-FRG. The NRE-FRG design is heavier, with the total active mass being 2.6 times higher than the RE-FRG, but with the estimated total active material cost of both generators almost the same. Moreover, the toque ripple for RE-FRG is 64% higher than for NRE-FRG. The demagnetization risk analysis was performed, and it is found that at higher temperatures, RE-FRG structures are prone to higher demagnetization risks, while it is much lower in NRE-FRGs. In summary, it is found that NRE-FRG is a suitable alternative to RE-FRG for medium-speed wind turbine generator applications in the 10-kW power range.
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Holcomb, Franklin H., Joseph Bush, James L. Knight, and Jason Whipple. "Energy Savings for Silent Camp™ Hybrid Technologies." Journal of Fuel Cell Science and Technology 4, no. 2 (August 1, 2006): 134–37. http://dx.doi.org/10.1115/1.2714566.
Full textAbstract:
In military base camp operations, the standard method of power generation is via the use of diesel generators. Unfortunately, these generators are often noisy and inefficient. Base camps could benefit from a “silent camp™” operation, in which power is supplied via low-noise, low-impact methods such as fuel cells. Base camps have a variable load profile (they use more power during peak hours than at other times), and low loading levels (their generators’ rated capacity is normally much greater than the load). Consequently, the generators only operate at peak efficiency for short, intermittent intervals. Under these conditions, the generators’ fuel use is less than optimal, they require frequent maintenance, and their life cycle is shortened. Approximately 60–70% of maintenance problems for diesel generators are directly attributable to “wetstacking,” which occurs when these generators are operated at less than 50% of their rated capacity (Commerce Business Daily, Feb. 16, 2000). One solution to address these issues is to institute a hybrid power system, consisting of: a fuel cell (with inverter), an electrolyzer, and a metal hydride storage system, all coupled and packaged with a diesel generator. This system would enable the generator to operate at peak efficiency while increasing the capabilities of the power generation system. Such a system could offer numerous benefits over the base case stand alone generator as follows: (1) the ability for Silent Camp™ operation (by using the fuel cell output exclusively); (2) potential for reduced fuel consumption; (3) reduced instances of “wetstacking,” thereby decreasing generator maintenance costs; (4) the ability to have backup power from fuel cells; (5) refueling capability for hydrogen devices or vehicles; and (6) reduced environmental impact in terms of pollutant, acoustic, and thermal emissions.