Improvement of the traction current asymmetry control system

The article presents approaches that allow modernizing the system for monitoring the asymmetry of the traction current. The existing systems of technical diagnostics and monitoring of the technical condition of automation and telemetry control devices, which have found wide application on the railways of JSC Russian Railways, do not allow monitoring the condition of adjacent railway transport infrastructure systems that affect the performance of railway automation and telemetry control devices. Besides, information about the condition of the object being diagnosed is sent to the monitoring center, while the operational and repair personnel do not have the necessary information and start working only after receiving information about the malfunction from the dispatcher of the monitoring center. The mobile device, proposed in the article, allows reducing the time necessary for obtaining information about the unserviceable condition of the railroad line. The article presents the analysis of gadgets planned for use in a mobile device, and the concept of the interface of the mobile application for technicians. It is noted that the hardware intended for use in a mobile device must provide protection against unauthorized access to the application, as well as have a high degree of protection against penetration. Besides, the article identifies the areas for further improvement of the traction current asymmetry control system.

NORMS AND METHODS FOR DETERMINING THE ELECTROMAGNETIC COMPATIBILITY OF MODERN AUTOMATIC LOCOMOTIVE SIGNALING SYSTEMS AND ELECTRIC ROLLING STOCK WITH AN ASYNCHRONOUS TRACTION DRIVE ON THE SUBWAY

The article provides a brief overview of the development and application of automatic control systems for subway trains. Modern automatic locomotive signaling systems featuring automatic speed control with signal transmission based on double-phase-diff erence modulation are analyzed. The introduction of electric rolling stock with an asynchronous traction drive and advanced train traffi c automation and remote control systems at the St. Petersburg Metro initiates the drive to ensure their electromagnetic compatibility. For the subway train traffi c automation and remote control systems, there have been no acceptance criteria for electromagnetic interference that occur in their operating range when electric rolling stock with an asynchronous traction drive is put into operation. The article identifi es the main sources of conducted electromagnetic interference and the routes of their penetration into the receive path of automatic locomotive signaling devices with automatic speed control. A method is proposed for determining the limits of hazardous and interfering eff ects (immunity limits) for automatic train signaling systems with automatic speed regulation of the systems of the BARS automatic speed control unit with phase-diff erence modulation and the upgraded PA-M (ПА-М) train automation with phase-diff erence modulation for the St. Petersburg Metro lines. A method is given for the transition from the immunity limits of automatic locomotive signaling systems with automatic speed control to the emission limits of electric rolling stock at diff erent traction current unbalance factors. A technique for measuring traction current at high-potential points on electric rolling stock is considered. A technique for assessing the levels of conducted electromagnetic interference from electric rolling stock by calculating the eff ective value in a sliding window of a pre-fi ltered traction current signal of an electric rolling stock is presented.

Simulation of the process of current distribution in a traction rail network

The article synthesizes a simulation model of a section of a traction rail network, analyzes the norms of permissible asymmetry current, at which a choke-transformer is able to function with a set quality. The simulation of the current distribution process that occurs in the traction rail network during the movement of trains of increased weight and length has been carried out. The graphs of the dependence of the asymmetry current on the traction current consumed by the electric rolling stock have been obtained, and the simulation of the dynamics of changes in the traction current in each of the rail lines has been carried out when the train was moving along a section of the traction rail network. Conclusions about the need to monitor the state of traction rail network elements, the service life of which in heavy traffic conditions is significantly reduced both due to dynamic loads and due to overheating due to the passage of increased traction currents have been made.

Studi Mekanisme Sedimentasi Formasi Dolokapa, Gorontalo

The Dolokapa Formation is a sedimentary rock formation formed in a deep-sea depositional environment with a fairly complex level of deformation and tectonic arrangement. Analysis of the sedimentation mechanism is carried out to determine how much tectonic influence on the mechanisms that occur in a depositional environment and the variations in the sedimentation mechanism formed. Research on the sedimentation mechanism needs to be carried out to determine the history of the formation of Gorontalo sedimentary rocks, especially in the Dolokapa Formation which was formed during the Miocene. The purpose of this study is to know the mechanisms of deep-marine sedimentation based on the identification of lithological characteristics, layer stacking patterns, and sedimentary structures. The method used was measuring sections using a range of ropes divided into four measurement paths. After that, a correlation was performed based on the genesis of deep marine formation. Based on the results of processing and analysis of the data, obtained units of lithology that insertion silty-clay, and the sandstone graining insertion of silt. In vertical succession, the layering pattern formed generally thickens upwards which describes the energy of the depositional currents. The sedimentary structure consists of rip up-clast, parallel lamination, graded bedding, convolute, slump, and trace fossils of nereites trace fossils of nereites that characterize the sedimentation of traction currents and turbidite currents in the deep-sea environment. The sedimentation mechanism formed is the traction current mechanism which is a further development of turbidite current and high-low concentration turbidity current mechanism that occurs slowly on a suspension-controlled grain. The stratigraphic relationship of the rock units in the research area is aligned based on the genesis formation that is located in the setting of the deep marine.

Synthesis of a device for anti-jamming reception of signals of tonal rail circuits on the background of additive five-component interference

An optimal receiving device for information signals of tonal rail circuits has been synthesized. The signals are observed against the background of an additive five-component interference. The first component of the interference is broadband Gaussian noise. The other four components of the interference are structurally determined: single impulse interference, interference from an adjacent tonal rail circuit, and multiharmonic interference from alternating traction current combined with the power line and from the locomotive traction converter. The presence of a complex of interference leads to errors in decision-making regarding the regulation of train traffic. This puts the participants in this movement before the danger of threatening emergencies. Therefore, it is necessary to develop and study means of noise-immune reception of information signals and the formation of dispatch decisions. The decision on the presence or absence of a signal is made by comparing two values of the mean square of the approximation error. This error is understood as the difference between the input voltage of the receiver and the sum of the signal with structurally determined interference. The first value of the error is calculated assuming the presence of a signal in a mixture with structurally determined noise. The second error value is calculated on the assumption that there is no signal in this mixture. The noise component is assumed to be present in both cases. The solution corresponds to a channel with a lower mean squared error. The block diagram of the device is presented. Analytically, it has been shown that the average value of the error in recognizing situations of presence or absence of a signal is two orders of magnitude less than the admissible value according to regulatory requirements. High noise immunity of the developed device will improve the safety of train traffic

PROBLEMS IN DEVELOPMENT OF ENERGY-SAVING TRACTION DRIVE

The problems of traction properties increase in locomotives are considered. The necessity in devices for instantaneous control of a friction coefficient of wheels and rails based on the impact of electric current or a magnetic field upon a wheel/rail contact area. There are defined basic fields of researches essential for the actual realization of such devices. It is defined that devices based on electric current impact require the introduction of considerable changes in the units of a crew part for wheel pair insulation and searches of problem solution in the separation of traction current and control one and the prevention of control current impact upon alarm systems. It is offered to consider magnetic amplifiers of adhesion as a solution of a short-term outlook which can be introduced in an existing locomotive fleet and those using current impact as a solution of newly-developed promising machines. There is offered a design of an individual traction drive simplifying a problem in the arrangement of devices for instantaneous control of a friction coefficient.

METHOD OF SPECTRAL ANALYSIS OF TRACTION CURRENT OF AC ELECTRIC LOCOMOTIVES

An improved method for spectral analysis of traction current of an Alternating Current (AC) electric locomotive is considered in the article. A new method of spectral analysis considers the change in voltage in the catenary system as a non-deterministic, non-ergodic and non-Gaussian process. It has been established that higher voltage harmonics in the catenary system have a significant negative effect on the operation of non-traction railway consumers of electricity. In addition, electric locomotives operating in the same feeder zone have a mutual influence on each other. Electric railway transport is a source of higher voltage harmonics and strongly distorts the shape of the sinusoidal voltage of the catenary system, which are caused by the higher spectral components of the current in the electric locomotive traction drive circuit. These spectral components of the traction current arise in the traction drive circuit due to the nonlinearity of the current-voltage characteristics of the electronic devices of an electric locomotive, for example, a contact rectifier, a capacitor circuit of traction motors. Reactive power compensators are used in electric locomotives to eliminate components of higher harmonic traction current in the catenary system. Traditionally, spectral analysis in such systems is performed using Fourier methods. However, the determination of the spectral components of the traction current by the Fourier method for constructing a control system for a reactive power compensator is possible only if the process of voltage variation is a deterministic or ergodic Gaussian process. Otherwise, the application of Fourier transform methods will be incorrect. An analysis of the factors that affect voltage changes in the catenary system showed that this process is significantly different from the ergodic Gaussian process. Such factors include the following: the operating mode of the electric locomotives; number and total capacity of electric locomotives in one feeder zone; electric locomotives passing through feeder zones; instability of collection current. Thus, in the case under consideration, the application of the Fourier methods is incorrect for the analysis of the spectral components of the traction current. This affects the quality of compensation of the higher harmonic components of the traction current, and in some cases, the unstable operation of the control system of the active part of the reactive power compensator. Proposed scientific approach is based on the Levinson–Durbin linear prediction algorithm. On the one hand, this allows adapting the control system of the compensator to the voltage parameters of the catenary system. On the other hand, this allows taking into account the operating modes of electric rail vehicle with reactive power compensation. The construction of a compensator control system using the Levinson–Durbin algorithm significantly simplifies thensynchronization scheme of the compensator and power circuits of the traction electric drive of AC electric locomotive. A comparison of the traditional method of spectral analysis, based on the Fast Fourier Transform (FFT), and the method, based on the Levinson–Durbin algorithm, proposed by the authors, showed the high efficiency of the latter.