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Vol 87, No 10 (2016)

Article

Improved designs of disk induction motors of block-module type for extreme environments

Vil’danov K.Y., Zabora I.G., Chernov R.O., Bespalov V.Y.

Abstract

The construction of new disk induction motors of block-module type, which are a part of motor-transformer units (MTUs), are considered. The induction motors are intended for operation in hermetic objects under extreme conditions: a gas, steam-to-gas, and liquid environment at high pressures (up to 150MPa) and temperature (up to +600°C). The primary winding of the transformer part of the unit is connected to a three-phase network, and the secondary z-phase bar winding is located in Z grooves of the magnetic conductor of a transformer closed on one side by a short-circuited ring. The motor part of the unit contains an induction motor with a short-circuited rotor and stator with bar uninsulated winding connected to the transformer secondary winding; on the opposite side, it is closed by a short-circuited ring. The induction motor can be implemented with a disk short-circuited rotor located between two disk stators with bar windings. The bars of the transformer secondary winding are connected with Z bar-shaped hermetic lead-ins installed in a hermetic partition. Each bar-shaped hermetic lead-in is connected at the other end with n bars of the stator winding through intermediate conductive arc-shaped segments adjoining the stator. The operating principle and operation features of new disk induction motors of block-module type are considered.

Russian Electrical Engineering. 2016;87(10):549-553
pages 549-553 views

The marine electrical power industry with the use of renewable energy carriers. Part 2. Axial multipole synchronous generators with permanent magnets for wind and wave offshore power plants

Khrisanov V.I., Dmitriev B.F.

Abstract

The paper deals with problems of selection of structures and optimum design of multipole permanent magnet synchronous machines (PMSMs) for operation in offshore wind- and wave-power plants under severe conditions for maintenance service. It is shown that multipole PMSMs are a new and very suitable electrical machine for direct connected turbogenerators in power plants and, at the same time, multipole PMSMs meet a number of other important demands, including high reliability, contactless construction, high efficiency, minimum mass and dimensions, and cost effectiveness. With the aim of systematization, an integrated classification scheme of PMSMs is presented to describe the variety of designs of stator and rotor configurations. With the help of a theoretical analysis based on a geometrical approach, analytical expressions for PMSM comparison are derived using the relationship between the criterion of optimization (maximum power density) and the main geometric parameters of PMSMs. Comparative analysis of the PMSMs with radial and axial magnetic fluxes for the case of various numbers of poles and different diameters of rotors has confirmed that axial multipole PMSMs are synchronous machines with maximum power density and an optimum variant for direct connected turbogenerator structures for offshore wind- and wave-power plants. It is noted that the advantage of axial PMSMs over radial PMSMs is monotonic growth in accordance with increasing number of poles p. Under the condition that p ≥ 20, which is strictly necessary for designing direct connected turbogenerators in offshore wind- and wave-power plants, we have more than doubled the power density at axial PMSMs as compared with radial ones.

Russian Electrical Engineering. 2016;87(10):554-559
pages 554-559 views

Design and implementation of electric drives and control systems for mining excavators

Malafeev S.I., Novgorodov A.A.

Abstract

Results of the design and application of new mechatronic systems with dc motors and transistor power transducers for mining excavators are considered. Intelligent motion control provides a high dynamic performance and individual adjustment of drives, eliminating impacts and passing into critical zones. The application of modern dc motor transistor transducers makes it possible to reduce power consumption by 20–30% compared to conventional excavators with Ward–Leonard drives and to reduce the specific power intensity of excavation. The power factor of the excavator is maintained constant and equal to a specified value in all operating modes, which ensures optimum electromagnetic compatibility of the excavator and a feeder line. New intelligent systems provide full control of all the main operating parameters of the excavator, loads on the working bodies, and the condition of all equipment components, as well as analysis and presentation in tabular and graphical form of the basic technological parameters of excavator performance (a volume of loaded mined rock, productive time, energy consumption, etc.). Intelligent systems contain a remote monitoring module. Results of the design and experience in commercial production and operation of mechatronic systems for single-bucket mining excavators with transistor power transducers as a part of main motion electric drives are given.

Russian Electrical Engineering. 2016;87(10):560-565
pages 560-565 views

Alternating traction current dynamics in track lines of double-track hauls

Shamanov V.I.

Abstract

The operational stability of track circuits and continuous cab signaling in electrified railway sections is disturbed most often by traction current noises in the track line. They are generated when asymmetrical traction current is produced at the points where track circuit equipment is connected to the tracks or under sending cab coils of continuous cab signaling. From the standpoint of traction current flows, a single-track haul track line can be considered a solitary double-wire circuit with two reciprocally induced singlewire electric circuits. As a result, traction current asymmetry becomes easier to calculate. In the case of double-track hauls, this problem is much more difficult to solve, because the traction network in these hauls additionally includes electrified trackways of adjacent tracks, second contact wire, and longitudinal power supply lines laid on catenary supports. These lines are reciprocally inductive with the considered trackways. The considered hauls are characterized by different distances from each trackway to additional electric lines, for which reason the reciprocal inductances inversely related to these distances are different as well. According to the analysis of the proposed procedure of calculating the traction current asymmetry in the track line, this asymmetry depends not only on electric resistances and specific reciprocal inductances of interlinked singlewire electric power lines, but also on the ratio of currents in these lines. It has been established that the absolute value of traction current asymmetry at a particular point of the track lines is indicated more adequately by the level of impact of traction current asymmetry on the operational stability of track circuits than by the traction current asymmetry factor. The time course of the traction current asymmetry in the track line depends on variations in the ambient temperature, traction current in the rails, and electric resistances in the junctions of parts of track bonds, choke jumpers, and ground circuits of catenary line supports. Additional changes in the traction current asymmetry under sending cab coils occur during train traffic and depend on the inbound resistances of track line sections ahead, as well as on any uneven longitudinal track magnetization.

Russian Electrical Engineering. 2016;87(10):566-571
pages 566-571 views

A new PMU based power swing detector to prevent mal-operation of distance relay

Ouadi A., Bentarzi H., Chafai M.

Abstract

In conventional transmission line protection, a distance relay is used to provide the primary as well as remote backup protection. The voltage and current phasors measurement needed by the distance relay for determining the impedance may be affected by the power disturbances such as power swing. Consequently, this power swing may cause mal-operation of Zone three distance relays which in turn may affect on the reliability of the whole protective scheme. To mitigate these effects and hence improve the relay reliability, this work proposes a new real-time power swing detector using phasor measurement units for blinding the distance relay only during this transient disturbance. However, this developed detector will not block relay when the power swing accompanied with faults. To validate the present work, the performance of developed enhanced distance relay is tested by signals generated by Simulink/MATLAB simulator under different conditions. The test results show that this proposed scheme provides good discrimination between the transient currents and the fault current which in turn it may contribute in enhancing the reliability of Distance relay.

Russian Electrical Engineering. 2016;87(10):572-578
pages 572-578 views

Genetically tuned fuzzy PID controller in two area reheat thermal power system

Ruby Meena A., Senthil Kumar S.

Abstract

This paper demonstrates the design and analysis of automatic generation control using intelligent genetic algorithm tuned fuzzy based controller. A two area thermal power system simulated for four different scenarios considers a reheat steam turbine in each area with Generator rate constraints. The Integral Time Squared Error (ITSE) employed to get an objective function for the optimization of controller gains. The simulation results compared with the conventional Proportional Integral Derivative (PID) controller, Genetic Algorithm (GA) tuned PID controller and GA tuned Fuzzy PID controller. The proposed GA tuned Fuzzy based PID Controller can generate the best performance for peak overshoot, undershoot and settling time with step load disturbances. Robustness of the performance of the proposed controller provided with system parametric uncertainties.

Russian Electrical Engineering. 2016;87(10):579-587
pages 579-587 views

Novel FGbSA: Fuzzy-Galaxy-based search algorithm for multi-objective reconfiguration of distribution systems

Tolabi H.B., Shakarami M.R., Hosseini R., Ayob S.B.

Abstract

Reconfiguration according to different criteria is an important problem in distribution systems. This paper presents a new method for optimal multi-objective reconfiguration of distribution system based on the Galaxy-based Search Algorithm (GbSA). To avoid the convergence problem, the input and output data are normalized in the same range using fuzzy sets. The main objectives of the proposed algorithm have been considered as power loss reduction, voltage profile improvement and increase of the system load balancing. The proposed technique has been investigated using the IEEE 33-bus test system and a real distribution network i.e. Tai-Power 11.4-kV distribution system. The obtained results revealed the superiority of the proposed fuzzy-GbSA method in terms of accuracy compared to the GbSA and other intelligent search algorithms such as Genetic Algorithm (GA) or Particle Swarm Optimization (PSO). Furthermore, the proposed algorithm efficiently converged to the optimum solution compared to the other intelligent counterpart algorithms.

Russian Electrical Engineering. 2016;87(10):588-595
pages 588-595 views