NASU Institute of Electrodynamics

Kiev, Ukraine

NASU Institute of Electrodynamics

Kiev, Ukraine
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Kucheriava I.M.,NASU Institute of Electrodynamics
Technical Electrodynamics | Year: 2017

The electric field distribution in the vicinity of stress cone of high-voltage XLPE insulated cable termination (110 kV) is studied by computer modeling. The dependence of cable insulation conductivity on electric intensity and the different cone positions relative to the cutting ends of the cable outer semiconducting layer and copper wire shield are taken into account. The stress control cone is considered both in the form of only cone reflector and as a complete stress cone with insulation body. The peculiarities of field distribution depending on the cone shape and surface roughness are analyzed. The attained results are of interest for designing and improvement of up-to-date high- and extra- high-voltage cable terminations.


Kuchanskyy V.,NASU Institute of Electrodynamics
2017 IEEE 37th International Conference on Electronics and Nanotechnology, ELNANO 2017 - Proceedings | Year: 2017

Due to the rising role of overhead lines extra high voltage there is a need of application of modern electronic devices that allow controlling modes of bulk electricity system. The switching control unit Switchsync F236 is one of such devices which enables to connect and disconnect contacts of poles circuit breakers at required time. This function of Switchsync F236 can be used not only for interruption of short circuit. One of the objectives of application Switchsync F236 is prevention of resonance overvoltage occurrence at closing extra high voltage line on no-load autotransformer. Durable resonance overvoltages may cause damage of electrical power equipment. This kind of overvoltages is caused by properties of the network and can be eliminated by changing the values of network parameters. Unlike switching overvoltages that exist centiseconds, resonance overvoltages not only occur unexpectedly, but they may go on for a long time until the automatic action or action of personnel will not change electrical schemes or mode. The resonant overvoltages are neglected when selecting insulation or parameters for high-voltage surge arrester as this protective measure is calculated to limit switching overvoltages, not to extinguish a long resonance process. Therefore, the probability and development of system accidents due to resonance overvoltages is significant. The importance of application and prevention of resonance ovevoltages caused research area which is presented in article. © 2017 IEEE.


Suprunovska N.I.,NASU Institute of Electrodynamics
Technical Electrodynamics | Year: 2017

The paper analyzes the interrelated cyclically repeated charge-discharge processes in the circuits of a reservoir capacitor in electric discharge installations with positive voltage feedback and a load whose resistance can vary randomly. Control of the amount of positive voltage feedback is characterized by coupling coefficient, which determine the relation of residual voltage of the capacitor discharge with the initial voltage of its subsequent charge. It is substantiated that the output voltage of electric discharge installations with positive feedback is limited in magnitude (due to energy losses in their circuits). In this case, it is possible to purposefully limit the excessive (as compared to permissible) increase in the capacitor charge voltage using an adjustable coupling coefficient 0 < k ≤ 1, which can be changed manually or automatically.


Rudenko Y.V.,NASU Institute of Electrodynamics
Technical Electrodynamics | Year: 2017

The mode of model averaging is proposed which allows to analyze the processes at pulse dc converters from general positions. Obtained model contains both parameters of average variable states, their ripples during period of steady-state regime and parameters of time intervals of converter state. The range of ratio between time constant of converter circuit and its operation period is grounded in which the error of model calculations is not more than 3%. The calculations using proposed mode and method of schematic simulation are fulfilled by the example of simplest step-down converter that confirms the high precision of results coincidence at mentioned range of parameters.


Kucheriava I.M.,NASU Institute of Electrodynamics
Technical Electrodynamics | Year: 2017

The paper studies the cable degradation mechanisms and electric field distributions in the polyethylene insulation of power cables with typical defects at macroscopic level including crack and numerous air bubbles in the insulation, protrusion of inner semiconducting layer, its air gapping with cable insulation and interruption along the cable conductor, holes in outer semiconducting layer, its delamination from copper shield as well as small air hole in the shield owing to corrosion. The three-dimensional computer modeling and analysis of electric field distributions are carried out in the chosen region of the cable containing the defects. The patterns of the distributions and local field enhancement in the vicinity of the defects are shown. The effect of defects on electric field in the polyethylene cable insulation is revealed.


Goncharenko I.S.,NASU Institute of Electrodynamics
2016 2nd International Conference on Intelligent Energy and Power Systems, IEPS 2016 - Conference Proceedings | Year: 2016

Constant growth of distributed generation (DG) in power systems has not only positive changes. Incorrect placement of DG can worsen steady-state parameters of a power grid, for example, power losses. The specific method of optimal DG placement and capacity, that has been developed previously, was improved. Now method determines the effect of installed DG on the power grid operation considering type and capacity of DG units, climatic pattern of installation region and different power grid steady-states. Method improvements have been tested on IEEE 14-bus test system using Monte-Carlo method. The results of simulation tests show viability of the updated method. © 2016 IEEE.


Shcherba A.A.,NASU Institute of Electrodynamics | Suprunovska N.I.,NASU Institute of Electrodynamics
Technical Electrodynamics | Year: 2014

It is performed the structure-parametric synthesis of the two-circuit and three-circuit electrical circuits with capacitive energy storage (CES) in the thyristor discharge pulse former (DPF) for supply of technological load, which electrical resistance depends on CES charge voltage and changes from one discharge to another stochastically. The discharge pulse former under consideration is realized both positive back coupling of charge voltage of reservoir capacitor from residual voltage its previous discharge and a negative one. Objective function of synthesis was a increasing of average pulse power in the load, and optimization criterions were the capacitor charge voltage, efficiency factor of discharge circuit and use energy factor of reservoir capacitor. The optimal parameters of elements of two-circuit and three-circuit capacitive energy storage circuits at which the maximum average pulse power in the load is attained are defined. The power and dynamic restrictions on objective function and circuit element parameters were taken into account.


Zakharchenko S.N.,NASU Institute of Electrodynamics
Technical Electrodynamics | Year: 2012

Results of research of dependence of equivalent electric resistance of a layer of metal granules from time and from a current proceeding in a layer on example Al are given. Characteristics of areas of dependence of resistance from time are described. The critical analysis of the functions approximating nonlinear dependence of resistance from a current by means of three known and one original criteria is carried out. It is shown that in the best way given dependence is described by hyperbolic function of the first degree on which basis the equivalent circuit of electric resistance of the granulated current-carrying medium is offered.


Golubev V.V.,NASU Institute of Electrodynamics
Technical Electrodynamics | Year: 2012

The design procedure and is offered to optimization of the target LC-filter of the converter of a AC voltage with a pulse regulator, active loading and high-frequency pulse-width regulation, simple engineering formulas for calculation of optimum parameters of the filter are received.


Bragynets I.O.,NASU Institute of Electrodynamics
Technical Electrodynamics | Year: 2013

The possibility of reducing the influence of low-frequency noise in the laser phase-frequency rangefinders, which leads to a short-term instability of converting links of the device has been reviewe. This is achieved through the use of filtering the output signal of the phase-frequency system, the frequency which is proportional to the measured distance. The electronic simulation of converting processes in such system was carried out for which the output signal models in analog and discrete form were received. The results of the simulation allow to choose optimal parameters for a high pass filter according to the allowable value of the error arising from the transition processes in it. By numerical simulations assessment of the random error of the device due to the influence of broadband noise has been carried out. The simulation results are presented as a function of the random error from the signal/noise ratio for the selected filter time constant. References 7, tables 2, figure 1.

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