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Theoretical aspects of selection of optimal design parameters of a new generation of AC transmission lines
Authors: Postolati V.M., Suslov V.M.
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Abstract: The problems of compactness and of a choice of optimal parameters of alternating current transmission lines are considered. Analytical analysis of some constructive characteristics of three variants of lines of new generation (one-chain, two-chain and operated self-compensated), for the purpose of their optimization by criteria of the maximum compactness is performed. |
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Keywords: transmission line, optimization, compactness.
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| 2 |
THE SOLUTION OF THE CABLE EQUATIONS BY MEANS OF FINITE DIFFERENCE TIME DOMAIN METHOD
Authors: Patsiuk V., Ribacova G.
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Abstract: The analysis and comparison of accuracy of numerical solutions received by Finite Difference Time Domain (FDTD) method and Godunovs method at the solution of the cable equations is carried out. It is demonstrated, that at sudden short circuits and at transition to idling mode in numerical solutions received by means of FDTD method for long lines with the distributed parameters appear strong nonphysical oscillations. It is shown, that the settlement scheme offered by authors on the basis of Godunovs method is deprived these lacks and provides high accuracy for the numerical solutions received at the analysis of dynamic modes in long lines, caused by sudden short circuits and line transitions in an idling mode. |
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Keywords: cable equations, finite difference time domain method, Godunov’s scheme.
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STUDY OF THE INFLUENCE LEVEL CURRENT OF THE SHORT CIRCUIT ON RELIABILITY OF THE BREAKERS
Authors: F. ERCHAN, V.POPESCU, IRINA LUPUSHOR, ANASTASIA MOCANU
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Abstract: In the article the analysis of the influence level current of the short circuit of the electrical equipment. It is designed the mathematical model allowing the modeling prototype reliability of the operation electrical equipment installed in nodes of the systems. |
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Keywords: power electric distributing systems, short circuit in power electrical systems, reliability of the breakers.
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THREE-STAGE SYNCHRONOUS OVERMODULATION CONTROL OF FIVE-PHASE INVERTERS
Authors: V. Oleschuk, G. Griva, R. Prudeak, A. Sizov
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Abstract: Novel three-stage algorithm of synchronous PWM control of five-phase inverter in the zone of overmodulation has been proposed and investigated. It provides smooth transition from linear modulation range to the ten-step operation mode of five-phase system at the maximum fundamental frequency, with full DC-bus voltage utilization. Simulations give the behavior of five-phase system during synchronous PWM control in the zone of overmodulation. |
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Keywords: five-phase voltage source inverter, synchronous pulsewidth modulation, increased output frequencies, smooth linear output voltage control.
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THE ASYNCHRONOUS MACHINE WITH THE MASSIVE FERROMAGNETIC ROTOR AND CAPACITOR EXCITATION
Authors: Birladean A.S.
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Abstract: An asynchronous machine with a massive ferromagnetic rotor of the various designs, improving its energy indicators is considered. Elaboration and experimental tests results of the asynchronous machine working in a generating mode at the lowered speed of rotation of a massive ferromagnetic rotor are presented. Conditions and possibilities of the asynchronous generator creation with capacitor excitation on the basis of the asynchronous machine with a massive rotor are shown as well. |
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Keywords: asynchronous machine, massive rotor, generating mode, asynchronous generator, excitation capacitor.
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Greenhouse Gas reduction for scenarios of power sources development of the Republic of Moldova
Authors: Ion Comendant, Sergiu Robu
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Abstract: For the new power market conditions, Moldova power sources development options up to 2033 are evaluated, and for the six scenarios selected the greenhouse gas reduction impact is determined. |
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Keywords: power sources, supply of electricity demand, greenhouse gas emissions.
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THE NATURAL COLD ACCUMULATOR AND VACUUM INSTALLATION FOR MILK COOLING IN REPUBLIC OF MOLDOVA
Authors: Cretu Victor
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Abstract: Based on theoretical and experimental research of the milk cooling process was elaborated mathematical model of accumulator with natural cold and vacuum installations, which allows determining the operating system installations, mentioned from environmental parameters. |
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Keywords: Use of energy, ecological system with natural cold and vacuum, vacuum installation.
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| 8 |
ONE OF THE WAYS TO RISE THE EFFICIENCY OF THE KISHINEV TOWN HEAT AND POWER STATIONS
Authors: Maximuk Е.P.
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Abstract: Methods to rise the efficiency of fuel using at town heat and power stations are discussed in detail. It is shown that application of hot water/exhaust absorption chillers allow to use heat energy surplus especially in warm season. As the results, the consumption of heat energy from the power stations is more constant during the year, the efficiency of fuel using is higher, and economics is better. Different technological schemes are discussed in detail. |
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Keywords: heat and power stations, hot water/exhaust absorption chillers, threegeneration.
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| 9 |
TRANSCRITICAL CO2 HEAT PUMP WITH EXPANDER-EJECTOR CYCLE
Authors: SIT BORIS, TIMCENCO DMITRII, SIT MIHAIL
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Abstract: Heat pump with expander – ejector cycle, method of this cycle control of this cycle and the scheme of the heat pump with the second loop are presented in this paper. |
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Keywords: heat pump, automatic control.
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| 10 |
THE THERMODYNAMIC CHARACTER OF INFORMATION
Authors: T.M.Popova
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Abstract: The article includes data concerning application of one of the universal method of the modern science based on fundamental thermodynamic laws to analyze the efficiency of the information processes. The comparison of the information and thermodynamic processes brought the author to the basic conclusion of the energetic character of information. |
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Keywords: efficiency, exergetic performance, loss of exergy.
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