scholarly journals Research of Ferr-Resonance Oscillations at the Frequency of Subharmonics in Three-Phase Non-Linear Electric Circuits and Systems

2020 ◽  
Vol 216 ◽  
pp. 01113
Author(s):  
M. Ibadullaev ◽  
A. N. Tovbaev
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Experimental Studies ◽  
Theoretical Research ◽  
Equivalent Model ◽  
Critical Parameters ◽  
Power Transmission Lines ◽  
Power Sources ◽  
Electric Circuits ◽  
Three Phase

It is known that the occurrence and existence of ferroresonant oscillations at the subharmonic frequency (SHC) in power transmission lines (TL) and in power supply systems is extremely undesirable, since they cause ferroresonant overvoltages at different frequencies. At the same time, there is a wide class of nonlinear electrical circuits, in which the excitation of autoparametric oscillations (AIC) at the frequency of the SHC forms the basis of frequency converting devices serving as secondary power sources. It is shown that three-phase nonlinear systems are in one way or another equivalent circuits for power transmission lines, the main elements of which are: longitudinal compensation capacitors, transverse compensation reactors, and transformers with a nonlinear characteristic. To study the regularities of the excitation and maintenance of SHC at a frequency in three-phase electro-ferromagnetic circuits (EFMC), theoretical and experimental studies of an equivalent model of a three-phase circuit with nonlinear inductance were carried out. For the analysis of the steady-state mode of the SHC at the frequency, the method of a small parameter (averaging) was applied. A shortened differential equation of motion for a three-phase nonlinear circuit is obtained. By solving them, the regions of existence of the SHC and the critical parameters of the chain were determined. The obtained results of theoretical research are confirmed by experimental studies.

scholarly journals Self-oscillations at the frequency of subharmonics in nonlinear electric chains and systems

2019 ◽  
Vol 139 ◽  
pp. 01054 ◽  
Author(s):  
M.I. Ibadullaev ◽  
A.N. Tovbaev ◽  
A.Zh. Esenbekov
Keyword(s):  
Single Phase ◽  
Experimental Studies ◽  
Power Lines ◽  
Equivalent Model ◽  
Critical Parameters ◽  
Steady State Mode ◽  
Power Sources ◽  
Electric Circuits ◽  
Three Phase ◽  
Extensive Class

It is known that the occurrence and existence of autoparametric oscillations (AIC) at the subharmonic frequency (GHC) in power lines (power lines) and in power supply systems is extremely undesirable, since they cause ferroresonant overvoltages at different frequencies. At the same time, there is an extensive class of nonlinear electric circuits in which the excitation of the AIC at the frequency of the SGC forms the basis of frequency-converting devices serving as secondary power sources. It is shown that single-phase-three-phase nonlinear systems are, to one degree or another, equivalent circuits of power lines, the main elements of which are: longitudinal compensation capacitors, transverse compensation reactors, and transformers with non-linear characteristics. The regularities of the excitation of the GCC at the frequency (ω / 3) of the power lines were studied, theoretical and experimental studies of the equivalent model of single-phase-three-phase circuits with nonlinear inductance were carried out. For a theoretical analysis of the steady-state mode of SGK at a frequency (ω / 3) with inductive coupling, the frequency- energy approach is used. The conditions of existence and critical parameters of the circuit are determined, and the mechanism of the appearance of the SGC at the frequency (ω / 3) is also studied.

On the General Theory for Analysis of Subharmonic Oscillations in Three-Phase Ferroresonance Circuits and Systems

2021 ◽  
pp. 35-44
Author(s):  
Muhtarhan IBADULLAEV ◽  
◽  
Akrom N. TOVBAEV ◽  
Azamat Zh. ESENBEKOV ◽  
◽  
...  
Keyword(s):  
General Theory ◽  
Initial Conditions ◽  
Experimental Studies ◽  
Input Voltage ◽  
Equivalent Model ◽  
Critical Parameters ◽  
Steady State Mode ◽  
Power Sources ◽  
Three Phase ◽  
Study Results

The general theory for analysis of subharmonic oscillations at a frequency of ω/3 in three-phase ferroresonance circuits is presented. The occurrence and existence of ferroresonance oscillations at subharmonic frequencies in power transmission lines and power supply systems is highly undesirable, since they cause overvoltages at various frequencies. At the same time, there is an extensive class of nonlinear electrical circuits in which the excitation of autoparametric oscillations at the frequency of subharmonics forms the basis of phase-discrete frequency converting devices serving as secondary power sources. To study the regularities of excitation and maintaining of subharmonic oscillations at a frequency of ω/3 in three-phase ferroresonance circuits, theoretical and experimental studies of an equivalent model of a three-phase circuit with nonlinear inductance were carried out. A generalized nonlinear differential equation for a three-phase circuit with mixed connection of its elements is derived. The steady-state mode of subharmonic oscillations at a frequency of ω/3 is analyzed using the small parameter (averaging) method, which made it possible to determine their existence domains and circuit critical parameters. A mathematical model and algorithm for calculating autoparametric oscillations have been developed to study the subharmonic oscillation excitation processes at a frequency of ω/3 in three-phase ferroresonance circuits depending on the initial conditions, circuit parameters and input voltage. The theoretical study results have been confirmed experimentally.

scholarly journals Powering Multiple Gas Condensate Wells in Russia’s Arctic: Power Supply Systems Based on Renewable Energy Sources

Resources ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 130
Author(s):  
Gennadiy Stroykov ◽  
Alexey Y. Cherepovitsyn ◽  
Elizaveta A. Iamshchikova
Keyword(s):  
Renewable Energy ◽  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Renewable Energy Sources ◽  
Operating Conditions ◽  
Gas Condensate ◽  
The Arctic ◽  
Power Transmission Lines ◽  
Power Sources

Using renewable energy off-grid power supply and choosing the right equipment that meets the operating conditions in the Arctic can provide companies with reliable power sources for producing gas at facilities located in remote areas and will reduce capital and operating costs associated with the construction of power transmission lines. For more than 15 years, a remote control system powered by renewable energy has been used in parallel with power transmission lines by Gazprom to operate its multiwell pads in Russia’s Far North, which validates the relevance of this study. The subject of the study is a group of gas condensate wells that consists of four multiwell pads operated by Wintershall Russland GmbH. The article discusses a stand-alone renewable-based power system as an option for powering remote oil and gas production facilities. The procedures used in the study include calculating such parameters as power output and power consumption, choosing equipment, describing the design features of a power supply system for a multiwell pad, conducting an economic assessment of the project, comparing different power supply options, analyzing project risks, and developing measures to mitigate these risks.

scholarly journals Comparative Analysis of Optical Signals Emitted by Corona on a Laboratory Model of Transmission Lines Made of Various Materials

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Sławomir Krzewiński ◽  
Paweł Frącz ◽  
Ireneusz Urbaniec ◽  
Tomasz Turba
Keyword(s):  
Transmission Lines ◽  
Optical Radiation ◽  
Power Transmission ◽  
Experimental Tests ◽  
Laboratory Model ◽  
Pure Aluminium ◽  
Power Transmission Lines ◽  
Optical Signals ◽  
Three Phase ◽  
System Operating

The paper presents results of comparative analyses of optical signals generated by corona discharges occurring in the vicinity and on the surface of power transmission lines made of five different materials under laboratory conditions. Three aluminium-based materials were chosen: pure aluminium, aluminium with added magnesium, and aluminium with added silicon, and for comparison purposes also, steel-based lines were considered: copper-coated steel and steel with added chromium and nickel. A three-phase triangular arrangement system operating under maximal voltage equal to 110 kV was applied for experimental tests. The optical radiation was registered using a spectrophotometer. During research works, also the influence of corona generation voltage and distance between power lines was investigated. Based on the achieved results, it was stated that the highest corona intensity was found for aluminium-based lines, for both pure aluminium and aluminium with added magnesium and silicon. The lowest corona intensity was observed for chromium- and nickel-alloyed (stainless) steel.

scholarly journals Application of the MQ RBF-FD method to calculating transient voltages of power transmission lines

2016 ◽  
Vol 19 (2) ◽  
pp. 5-15
Author(s):  
Anh Pham Lan Vu ◽  
Viet Quoc Le ◽  
Tu Phan Vu
Keyword(s):  
Finite Difference ◽  
Transmission Lines ◽  
Power Transmission ◽  
Power Transmission Lines ◽  
Finite Difference Approximations ◽  
Transient Problems ◽  
Benchmark Circuit ◽  
Three Phase ◽  
Phase Transmission ◽  
Transient Voltages

This paper presents an application of the Radial Basis Function – Based Finite Difference Method (RBF-FD) to solving the electrical transient problems defined by the time-dependent ordinary differential equations. In this method, the finite difference approximations of first- and second-order derivatives in time domain are formalated the same as those in space domain based on the MQ (Multiquadrics) function presented in [1]. The MQ RBF-FD method are for the sake of evaluating the accuracy, effectiveness and applicability used to compute the transient voltages on the benchmark circuit and 220 kV three-phase transmission line of Viet Nam. Our numerical results are compared with those obtained by the analytical method, the traditional FD method and ATP/EMTP software. The compared results have been shown that the MQ RBF-FD method has accuracy that is higher than ones of the traditional numerical methods, especially with the optimal shape parameter.

scholarly journals Restoring normal network operation mode by automatically disabling network ATS

2020 ◽  
Vol 178 ◽  
pp. 01072
Author(s):  
A.V. Vinogradova ◽  
A.I. Psarev ◽  
A.V. Vinogradov ◽  
V.E. Bolshev ◽  
M. Jasinski ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Load Transfer ◽  
Power Transmission ◽  
Operation Mode ◽  
Power Transmission Lines ◽  
Initial State ◽  
Power Sources ◽  
Normal Network ◽  
Network Operation

Automatic sectionalizing and redundancy of power transmission lines is one of the conditions for network intellectualization and can significantly reduce the power supply interruption time for rural consumers. However, both sectionalizing and redundancy of power transmission lines in 0.4 kV electric networks are used extremely limitedly since there are no sufficiently effective methods and technical means for their implementation. This article presents a method to automatically deactivate the automatic load transfer switch when restoring the normal network operation mode. The paper considers the implementation of the method on the example of damage occurring in the network where power is supplied to consumers from two power sources using an automatic load transfer switch and two sectionalizing units. A device is developed which allows implementing the developed method of automatic load transfer switch deactivation. The device consists of sectionalizing unit, automatic load transfer switch, voltage presence sensor, power direction sensor, memory element, repeater element, element AND and 3 elements NOT. The work of the device is described. The proposed method for automatically disconnecting the automatic load transfer switch in order to return the consumers’ power supply circuit to its initial state solves the problem of eliminating unreasonable power supply interruptions for consumers.

scholarly journals Evaluating through mathematical modelling the power equipment busbars electrodynamic strength under sudden short-circuit conditions

2018 ◽  
Vol 210 ◽  
pp. 02004
Author(s):  
Cornelia A. Bulucea ◽  
Constantin Brindusa ◽  
Doru A. Nicola ◽  
Nikos E. Mastorakis ◽  
Carmen A. Bulucea ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Power Transformer ◽  
Short Circuit ◽  
Simulation Models ◽  
Electrical Equipment ◽  
Power Transmission Lines ◽  
Electric Circuits ◽  
Mechanical Deformations ◽  
Electrodynamic Forces

The electrodynamic strength, as forces acting between the current-carrying electric circuits are exerted as long as the currents exist, and have the tendency of deformation and displacement of the circuits. In short-circuit regimes the strength in electrical equipment becomes severe. For instance, short-circuits highly affect power transformers connected to power transmission lines. The effects are also strong because of mechanical deformations occurring in the power transformer connection part. In line with this idea, in this paper it is made an analytical study upon the a.c. single-phase and a.c. three-phase electric circuits, taking into account the current instantaneous maximum value. The paper also entails numerical simulations of electrodynamic strength in power transformer busbars under short-circuit conditions. MATLAB software, with its specific extensions, enable simulation models to generate the charts of the electrodynamic forces in the power transformer connection bars.

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