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A method for calculating a switched inductive-capacitor generator has been developed that makes it possible to determine the voltages, currents, power, and efficiency of the generator taking into account the parameters of its elements in a pulse-frequency mode of power supply of an active-inductive load. To increase the efficiency of the generator, the voltage across the capacitor and the power of the generated current pulses in the load, it is necessary to increase the source voltage, the switching voltage of the dynistors (Shockley diodes), the switching frequency and duty cycle, the number of capacitor-charging periods, and the time constant of the inductive storage, as well as reduce the capacitance of the capacitor. A generator with a source voltage of up to 48 V and a current-pulse frequency in a load of 1 Hz can have a pulse energy of up to 12 kJ, an average power of up to 12 kW with an efficiency of up to 0.89 and a pulse power of up to 35 MW. It is possible to connect the generator to a source with an insufficient dc voltage level for charging the capacitor, with the voltage across the charged capacitor (639–3060 V) being able to be tens of times higher than the source voltage (12–48 V). [ABSTRACT FROM AUTHOR]

A technique for calculating the parameters of a transformer without a magnetic circuit with two cylindrical coaxial multilayer windings of the same length has been developed. Such parameters as inductance, resistance, capacitance, and temperature of windings are determined, which are used to calculate periodic voltages and currents in the steady-state power supply mode of the active load, when the primary winding of the transformer is connected to the voltage inverter. The formulas for calculating the transformer parameters, voltages, and currents, which are obtained based on the equations of electromagnetic fields and electric circuits, are programmed using the Mathcad software. The method's reliability is confirmed by a satisfactory agreement between the calculated and the experimental values of the transformer parameters, as well as by similar calculated and experimental values of periodic voltage on the resistive load. The results obtained testify to the possibility of the efficient use of transformers without magnetic circuit with high coupling coefficient at sufficiently high frequencies, when the quality factors of the windings are high, the surface effect in the conductors of the windings is negligible and the undesirable shunting effect of parasitic capacitances in the windings is still insignificant. [ABSTRACT FROM AUTHOR]

This article describes a procedure for predicting the parameters of an electromagnetic field in thin flat metal sheets of magnetic cores, screens, and busbars in a pulse regime. The following parameters have been determined: magnetic intensity and current density, thermal and magnetic energy, temperature, magnetic flux and electric current, resistance and inductance, and acceptable thickness of the sheets. These parameters have been determined with consideration for the physical properties of materials and sizes of the sheets, as well as the amplitude, shape, and duration of a pulse of magnetic intensity on a sheet surface. The procedure that has been developed is based on solving the equations of an electromagnetic field by the operator and frequency methods, as well as using Duhamel's integral. The obtained equations can be applied, for instance, in the Mathcad environment for engineering predictions of magnetic cores, screens, and busbars in a pulse regime during their automated engineering. The reliability of the procedure has been confirmed on the basis of a coincidence of magnetic intensities obtained by the frequency method and Duhamel's integral. [ABSTRACT FROM AUTHOR]

In this paper, we ground a method for calculating switching overvoltages including the discharge of lightning currents into the contact network and into a high-voltage power wire (HVPW) to isolate the contact network in the power supply system with the HVPW. It was established that the protection of outdoor signaling, centralization, and blocking (SCB) devices from switching overvoltages in a power supply system with a high-voltage power wire (PSS HVPW) can be solved by connecting the reinforcement of the support foundations of the contact network to an extended artificial grounding conductor (GC) located under the ground and not connected to the rail track. The use of a GC, along with limitation of pulse overvoltages on the insulation of the contact network supports, solves the problem of ensuring reliable protection of the traction networks from short-circuit currents in the traction network. An algorithm for calculating the voltage of the zero sequence of phase voltages of overhead power lines (OPLs) with an isolated neutral relative to the ground when they are located in the zones of electromagnetic influence of the PSS with the HVPW was developed. Due to the electrical effect of the HVPW voltage, the induced voltage in an OPL is shown to reach values ​​that significantly exceed the levels allowed by regulatory documents. An analysis of the obtained results indicates the feasibility of placing OPL wires on free-standing supports outside the reserved strip. The need for such a solution is also determined by keeping the HVPW voltage from entering the OPL wires, with their possible breakage. [ABSTRACT FROM AUTHOR]

The paper considers a twelve-pulse rectifier circuit based on the ring circuit with equalizing reactor. Analysis of the scheme revealed several positive qualities in comparison with those known. These include the same duration of current flow through the gates equals 120 el. deg, simultaneous parallel operation of two gates in the ring circuit, unified construction of transformer secondary windings (two star connections or two triangle connections), and the possibility of connecting an additional load to the zero taps of secondary winding and simultaneous operation with the different loads as in the six- and twelve-pulse modes. The operating principles of this circuit are considered, and general equations for the calculation of transformer, gate elements and equalizing reactor are given. The results of simulation and experimental verification of the model sample in all modes are the basis for its practical use. Waveforms are shown for the simulation and experimental results. Circuit simulation for the parameter values corresponding to the elements of the model sample showed a possible increase in efficiency and decrease of the losses in semiconductor devices for up to 20%. [ABSTRACT FROM AUTHOR]

A patented ring circuit with an equalizing reactor is considered in uncontrolled and controlled operation. After theoretical analysis, simulation, and experimental verification of the circuit, its parameters are determined. [ABSTRACT FROM AUTHOR]

The switching conditions of nonloaded transformers have been investigated to understand the effect of current inrushes and limitations by considering the connecting circuit of the windings, magnetization performances, contact parameters, type of switcher drive, and the value and sign of residual magnetization. The peak-switching currents have been calculated, simulated, and measured and the results have been compared. The obtained results make it possible to increase the power efficiency of the facility by decreasing the losses and maintainign the quality factor of electric power in transient modes. [ABSTRACT FROM AUTHOR]

The functional dependences of relative harmonic amplitudes and the factor of the form of the current of the power source versus the space factor, as well as the number of phases and phase displacement for a multiphase pulse chopper, are established. The optimum phase displacement values, which minimizes power losses in the source circuit, are determined. The dependences of the mean value form factor and the mean ratio of the power losses in the source circuit for the impulse and rheostatic control versus the number of chopper phases are obtained. It is shown that, from the standpoint of reducing the power losses in the source circuit, the increase in the number of chopper phases n > 2 is not effective. [ABSTRACT FROM AUTHOR]

A vector ratio of current and voltage distortions in a three-phase system that fully takes into account all distortion phenomena is suggested. The techniques of measuring this ratio are considered and examples of measurements are given. [ABSTRACT FROM AUTHOR]

A simplified way of calculating the current frequency of induction self-excited generator with two distributed windings on the stator is suggested. It is shown that iron losses do not influence the current frequency of the generator; therefore, to simplify calculations, it is possible to neglect them. [ABSTRACT FROM AUTHOR]

A new measurement system is considered that contains a fiberoptical waveguide that implements galvanic isolation (separation) between measurement and operator areas (zones) serves for transferring (transmitting) measurement information from the measurement area to the operator area, as well as for transferring optical radiation in the measurement area. The energy of this optical radiation is converted to the electrical energy to supply (power) at the circuit of the remote module (unit). In contrast to known hybrid measurement systems for measuring the current strength, this system enables the measurement of a number of the parameters, namely, the current, frequency, phase, and temperature of a current-carrying wire. [ABSTRACT FROM AUTHOR]