Mathematical simulation application for research of nonuniform distributed-parameter circuit transients

This paper considers the simulation capability of nonuniform distributed-parameter circuit transients by using MatLab Simulink. This approach is capable of determining currents and voltages of nodes for power networks of any configurations and modes. The paper contains results of nonuniform line simulations in idle, short-circuit and load modes

Calculation of the surface effect in the ferromagnetic conductor with the harmonic electromagnetic field

The authors of the paper have obtained formulas for analytical calculation of the constants with the harmonic electromagnetic field, which characterize the surface layer (a skin layer) of the ferromagnetic conductors in case of heating and nonlinear magnetic properties, which can be used for practical calculation of the electromagnetic screens, rotors of the electrical machines and inductive heating installations. A nonlinear dependence of the magnetic induction on the magnetic tension of the ferromagnetic conductor is replaced by one or two linear sections. It is considered that the skin layer of the conductor has constant quantities of the specific conductivity and averaged temperature. Linear electrodynamics equations are solved for the conductive half-space. Parameters of the ferromagnetic conductor's surface layer are calculated: magnetic permeability, the thickness of the skin layer and its averaged temperature, exposure time of the electromagnetic field on the conductor with the established maximum temperature on the conductor's surface, pressure of the field on the conductor and its resistance, inductivity of the internal magnetic field in the conductor, the thermal energy capacity. The methods credibility is confirmed with the concurrence of the resistance and inductiviry of the ferromagnetic conductor with analogous quantities from other methods

The frequency-domain method of calculation for the pulsed electromagnetic field in a conductive ferromagnetic plate

The technique for parameters determination of magnetic skin effect on ferromagnetic plate at a specified pulse of magnetic field intensity on the plate surface is proposed. It is based on a frequency-domain method and could be applied for a pulsing transformer, a dynamoelectric pulse generator and a commutating inductor that contains an imbricated core. Due to this technique, such plate parameters as specific heat loss energy, the average power of this energy and the plate temperature raise, the magnetic flux attenuation factor and the plate q-factor could be calculated. These parameters depend on the steel type, the amplitude, the rms value, the duration and the form of the magnetic field intensity impulse on the plate surface. The plate thickness is defined by the value of the flux attenuation factor and the plate q-factor that should be maximal. The reliability of the proposed technique is built on a common frequency-domain usage applicable for pulse transient study under zero boundary conditions of the electric circuit and the conformity of obtained results with the sinusoidal steady-state mode

Mathematical model for the power supply system of an autonomous object with an AC power transmission over a cable rope

A modeling problem of the power system, which provides an AC power transmission to a submersible device over the conducting rope, was considered. The power supply system units and their parameters are described. The system multi-dimensional mathematical model in the variables state space with regard to the nonlinear characteristic of system elements is proposed

Regularising algorithm of parameter identification of electric charge equivalent circuit

A new algorithm of parameter identification of equivalent circuit for electrical charge replacement is suggested. The approach is based on the solution of integral equation of the I type with respect to the function of indicial admittance, by which then determination of replacement circuit parameters is carried out. Application of smoothing splines and original regulating algorithm including kernel setting error of integration equation permits to obtain a stable algorithm of parameter identification. The investigation of algorithm shows high calculating efficiency and sufficient accuracy of parameter identification

The power supply system model of the process submersible device with AC power transmission over the cable-rope

A practical problem of power supply system modeling for the process submersible device with AC power transmission over the cable-rope was considered. The problem is highly relevant in developing and operation of submersible centrifugal pumps and submersibles. The results of modeling a symmetrical three-phase power supply system and their compliance with the real data are given at the paper. The obtained results in the mathematical and simulation models were similar

Soliton solution of electromechanical transient processes in electric power systems

Бесперебойное электроснабжение нефтяных и газовых месторождений остается важнейшей задачей мировой экономики. Одним из важнейших факторов, влияющих на отключение электроснабжения месторождений, является нарушение устойчивой работы генераторов. Устойчивая работа генераторов может быть нарушена при возникновении переходных процессов, вызванных короткими замыканиями или импульсными воздействиями на линии электропередач. При этом в электроэнергетической системе могут возникнуть уединенные волны – солитоны, характеризующиеся большой амплитудой и высокой скоростью распространения волны. В данной работе описываются причины возникновения таких волн. Приводится решение волнового уравнения электромеханической системы электроэнергетики, описывающего распространение уединенных волн. Решение рассматривается в фазовой плоскости, приводится численный пример расчета солитонного решения. Цель: найти солитонные решения в переходных процессах электромеханических систем и объяснить причины их возникновения, дать объяснения этого физического явления, определить, какую роль это явление играет в оценке устойчивости работы генераторов и предложить мероприятия по устранению нарушения устойчивости при наличии солитонной волны. Методы: метод фазовой плоскости, численное решение дифференциального уравнения методом Рунге– Кутта, метод пространства состояния. Результаты. Обнаружено, что при приближении решения уравнения турбина–генератор к границе динамической устойчивости возникают солитоны – одиночные всплески величины угла генератора. Выводы. При распространении эти волны ведут себя как частицы, что позволяет производить анализ обмена энергиями (потоками мощности) так же как анализ обмена энергиями механических частиц. При нарушении устойчивости возникают гармонические колебания, которые преобразуются в группу солитонов, распространение которых можно рассматривать как распространение частиц.The paper introduces the solution of the wave equation of the electromechanical system of electric power engineering in the form of a soliton - solitary wave. The causes of such waves are described. The solutions are considered in the phase plane, a numerical example of the soliton solution was given. The main aim of the research is to find the soliton solutions in transients of electromechanical systems, and explain the causes of their occurrence, explain this physical phenomenon, determine the role this phenomenon plays in the sustainability assessment, and propose the measures to eliminate the violation of stability in the presence of a soliton wave. Methods: phase plane method, numerical differential equation by the Runge-Kutt method, state space method. Results. It was found out that when the turbine-generator equation solution is approaching to the dynamic stability boundary, the solitons - solitary waves of the generator angle - appear. Conclusions. These waves behave like particles at propagation, that allows analyzing the exchange of energies (power flows) as the exchange in mechanical particles with energies. When stability is violated, harmonic oscillations arise, which are transformed into a group of solitons which propagation can be considered as the propagation of particles