Browsing by Author "Sheikina, Olha H."
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Item Determination of Energy and Electric Capacity of On-Board Supercapacitor Regenerative Energy Storage(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2021) Kostin, Mykola O.; Mukha, Andrii M.; Sheikina, Olha H.; Kurylenko, Olena Ya.ENG: Purpose. Development of a method for determining the main functional parameters of on-board supercapacitor recuperative energy storage based on the asymptotic theory of extreme statistics by Gumbel, taking into account sto-chastic nature of changes in recuperated voltage and current. Methodology. To achieve this purpose, methods, devices and computer systems for temporary registration of recuperated voltages and currents on operating electric locomotives, methods of the theory of random processes and methods of probabilistic and statistical processing of registro-grams of voltages and currents were used. Findings. A computational and experimental method for estimating recu-perative energy has been proposed and practically applied. A probabilistic method has been developed for determining the energy and electric capacity of on-board supercapacitor recuperative energy storage units. Numerical probabilistic and statistical calculations of the energy and electric capacity of on-board storage for the VL8 and VL11M6 electric locomotives during their operation in the sections of Prydniprovska railway have been carried out. It was found that the energy and electric capacity of on-board storage devices are distributed according to an exponential law with a clear prevalence of their minimum values and in compliance with direct proportionality between them. Originality. For the first time, an autonomous phase of recuperative braking mode of an electric rolling stock has been developed, which makes it possible to significantly reduce the mass and dimension of a supercapacitor storage. The asymptotic theory of extreme statistics by Gumbel was adapted to the method for calculating energy and electric capacity of an on-board storage device, which made it possible to take into account the influence of stochastic nature of changes in the recuperated voltage and current. The probabilistic influence regularities of the change nature in the recuperation energy on the capacity of on-board storage in the phase of recuperative braking have been established. Further development was obtained by a computational-experimental method for assessing the recuperative energy, based on monitoring and using the time dependences of voltage and current obtained in real modes of recuperative braking. For the first time in electric traction systems, it was proposed to carry out the transition from the recuperative braking mode to the recuperative regeneration mode. Practical value. The developed method and technique based on it make it possible to evaluate functional parameters of on-board storage device of all types of electric rolling stock, considering stochastic nature of recuperated voltages and currents. Numerical-graphic dependences of the energy in-tensity and capacity of the on-board storage are recommended for predicting and evaluating these parameters for various modes of recuperative braking. Since the task of designing an on-board storage unit (in terms of mass and dimensions) is ambiguous, therefore, in each specific case of the type of electric locomotive and recuperation modes, it must be solved individually, taking into account the probability of the corresponding capacitance values.Item Fryze Reactive Power of Trams in Eeffective Stochastic Rrecuperation Processes(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Bondar, Oleh I.; Kostin, Mykola O.; Mukha, Andrei; Sheikina, Olha H.; Levytska, Svitlana І.ENG: Abstract. Urban electric transport system, particularly tram systems, is not a direct current system not only in traction mode but in regenerative modes as both voltage on a collector and regenerative current are stochastic abruptly variable processes. The above- mentioned facts determine availability of Fryze’s reactive power in this system that flows from a railway substation to trams, leads to incidental losses of energy and significantly reduces its quality. So evaluation of power effectiveness of the system in electrical trams operation is impossible without determining the level of reactive power in this system. We have analytical expression of reactive power by Fryze. Numerical calculations for trams type T3D and T4D in regenerative braking modes are done. Probabilistic statistical data processing operation of reactive power expressions is done. It is determined that reactive power changes in the limit of 10…100 kilo-volt ampere reactive with mathematical expectation – 37,0 kilo-volt ampere reactive. Statistical allocation of random power values are different. Numerical calculations of incidental losses, energy of recuperation are done and they range supplementary – 20% from total losses. It is stated that coefficient of reactive power of system route of trams is exceeding permissible value 0,25.