Том 87, № 5 (2016)

Some aspects of the construction of power quality control systems in power supply systems are discussed. The basic requirements for quality factors of electric power are determined, the conditions of joint parallel operation of energy consumers are considered, and analysis of traditional ways of solving the emerging problems is carried out. The advantages and disadvantages of power quality control systems related to the capabilities of new technologies with application of high-power semiconductor switching devices (GTO and IGCT thyristors, MOSFET and IGBT transistors) are considered. The application of computer technology in power quality control systems makes it possible to use rather complicated and effective algorithms of numerical processing of signals and significantly increase the accuracy of correction of disturbances in electric networks. The advantages and disadvantages of industrial plants constructed in the form of a controlled reactor with a dc magnetic bias and a reactor with a thyristor key are considered. Two types of devices to compensate for possible disadvantages are identified: devices using fully controlled keys and devices ones using artificial commutation and incompletely controlled power keys. A brief analysis of the known methods of electric power quality control is implemented. Recommendations for the establishment of power quality control systems are suggested in which the parameters of software depend on the solution algorithm of a posed problem, while the algorithm itself depends on the method of control and mathematical laws on which it is based. The method of control determines the structure of the power quality control system, while the software determines the basic operations of information processing, their quantity, the scheme of data processing, the volume data flows, etc.

Centralized power supply systems for passenger and special trains with generator cars (GCs) are characterized by a lower specific weight and cost of equipment and lower service and repair expenses, as well as the possibility of using the standard general-purpose electrical apparatus. Their disadvantages include a large amount of noxious atmospheric emissions when diesel generators with a load less than the rated value are in operation and a high noise level. This hinders the operation of GCs at stations and depots and in tunnels. Designing combined power systems in which alternative energy sources, particularly as regards electrochemical generators (ECG) characterized by the absence of noxious atmospheric emissions, low noise level, higher efficiency increasing with the loads lower than the rated ones are used along with diesel generators is a method of improving the ecological performance of generator cars. The power control methods, the principles of control system construction, and the variants of the structure and an ECG energy channel operating with a voltage inverter in parallel to a synchronous generator are discussed in this article. The possibility of controlling the active and reactive powers of the ECG energy channel within a wide range by changing the modulation coefficient and the initial phase of the master effect of the voltage inverter is shown. A block diagram of the control system providing high speed and satisfactory quality of the transient processes in the energy system with the GC is proposed. The mathematical modeling method is used to indicate the possibility of ensuring a satisfactory quality of electric energy on the channel output (the total harmonic distortion does not excess 10–12%) with a rather high efficiency (80–88%) over the total power range.

A problem of evaluating the possibility of a proposed devise to limit motor current when supply voltage is restored after a short period of separation of a pantograph from a contact wire is formulated. An analysis of the transient processes in the circuits of the traction commutator motors under transient operation modes of the electric stocks and the current limiter in the course of voltage recovery on the pantograph after its separation from the contact wire, the assessment of the variants of feeding the excitation winding; calculation of the parameters of the proposed current limiters; development of variants of computer models; and investigation of the transient processes in the traction motor chain at the supply voltage recovery are carried out in the present article. The effect of excitation winding feeding on the additional power source, as well as the area of possible limitation and exclusion of the motor current inrushes I the course of voltage source recovery, are estimated. The variants of the discharge of the storage element on the excitation winding and the relationships between the capacitor parameters depending on the required value of the winding voltage are considered. A method of controlling excitation winding current from an independent source is implemented. The use of the method and the protection device allows one to increase the commutation resistance of the traction motors at the inrushes or the voltage recovery after loss of the contact of the pantograph with the contact wire, to decrease the possible commutation violation, and to reduce the number of failures.

This article is devoted to solving the problem of determination of rates of electric rolling stock conductive interference on the mechanisms of subway track circuits using the example of SUE Petersburg Subway System. This allows us to investigate the electromagnetic compatibility of rolling stock and train traffic control devices, first of all, track circuits. These problems are solved using the electromagnetic compatibility theory. Some features of the interference that appear during track circuit operation are described in this paper, including separation of interference to danger and interrupting. The investigation has shown that the requirements for the interference current that is generated by the rolling stock should be standardized for investigating the electromagnetic compatibility of electric rolling stock with a frequency motor and track circuit equipment. The main information from the standards based on the research is given. The rates of danger and interrupting interference on the rolling stock currents are given. Also the rates of interference currents in the audio frequency track circuits and the track circuits with the frequency of 50 Hz, and the rates of interference currents in the rails for specified asymmetry coefficient are given.

Modern railway automation and remote control systems are equipped with advanced self-diagnostics facilities. This article is devoted to the development of continuous technical state control of turned-off signal lamps. Application of pulse control using special pulses is proposed. The advantage of such a control circuit is its low sensitivity to the shunting effect of the signal transformer magnetizing inductance. The correct selection of the pulse parameters allows one considerable decreasing the shunting influence of the cable line capacity. It is shown that the pulse test circuit can be implemented by means of the up-to-date contactless semiconductor component base. The pulse control principles of the turned off signal lamps are discussed. An engineering solution enabling one to generate test pulses 5 ms in duration with a time interval of 200 ms is given. The signal processing principles on the control circuit output are considered. The aforementioned solution is integrated to the structure of the signal lamp control power module.

Special linking circuits are required for the design of safe railway automation and remote control of trackside objects. They are usually based on devices with an asymmetrical failure rate, mainly first reliability class electromagnetic relays. The development of railway automation and remote control devices requires the use of state-of-the-art contactless semiconductor components. In this case, the use of functional converters or periodic testing of semiconductor switches and disconnection of the power supply from control objects in case of faults are needed. This article describes the use of a three-phase induction motor as the solution of the problem. They are used for the design of functional converters for railway automation electric motors control. It is proposed to use the low-frequency mode of power switch operation (switch frequency is 50 Hz) and to abandon the pulse-width modulation. The suggested technical solution is used in a CBI-MPC system for train traffic control at stations developed at the Center for Computer Railway Technologies of St. Petersburg State Transport University.