scholarly journals Trends in Improving Sensors for Controlling the Condition of Track Sections

2021 ◽  
Vol 264 ◽  
pp. 05045
Author(s):  
Ravshan Aliev
Keyword(s):  
Traffic Safety ◽  
Voltage Regulation ◽  
Rate Of Change ◽  
Electrical Parameters ◽  
Reliable Operation ◽  
Longitudinal Asymmetry ◽  
Compensation Methods ◽  
Track Circuits ◽  
Current Value ◽  
Element Base

Various principles can be used to implement intelligent track circuits: voltage regulation of the power supply, compensation methods for switching on rail lines and track circuit devices, receiver sensitivity adjustment, comparison of two electrical parameters of one, two, or more track circuits, as well as a combination of these methods. At present, such improvement of track circuits is becoming relevant, which would make it possible to exclude from the circuits one of the most unreliable elements - an insulating joint, use a modern microprocessor element base in devices for monitoring the state of track sections, thus ensure their reliable operation. This will significantly reduce the costs of building and operating interval control systems and increase train traffic safety. These requirements are met by intelligent track circuits, which consider the current value of the insulation resistance, the rate of change of this resistance, and the longitudinal asymmetry.

scholarly journals Investigation of Var Compensation Schemes in Unbalanced Distribution Systems

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Yinuo Huang ◽  
Licheng Wang ◽  
Kai Wang
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Low Voltage ◽  
Current System ◽  
Voltage Regulation ◽  
Voltage Sensitivity ◽  
Compensation Methods ◽  
Distribution System Planning ◽  
Var Compensation ◽  
Phase Conductors

Distributed rooftop photovoltaic (PV) generators prospered distributed generation (DG) in recent years. Certain randomness of rooftop PV connection may lead to significant PV power imbalance across three phases, especially in low-voltage distribution systems. Due to interphase line coupling, traditional Var compensation methods which typically have competent voltage regulation performance may become less effective in such PV imbalance scenarios. In this paper, the limitation of traditional Var compensation methods in voltage regulation with unbalanced PV power integration is demonstrated and comprehensively analyzed. After describing the voltage regulation challenge, based on the voltage sensitivity analysis, it is revealed that PV power unbalanced level together with equivalent mutual impedance among phase conductors has a significant impact on the effectiveness of traditional Var compensation methods on voltage regulation. On this basis, to improve the performance of voltage regulation methods, some suggestions are proposed for both current system operation and future distribution system planning. Numerical studies demonstrate the effectiveness of the proposed suggestions. Future rooftop PV integration in LV systems can benefit from this research.

scholarly journals Investigation of train shunt problem in track circuits of signalling and interlocking devices

2019 ◽  
Vol 294 ◽  
pp. 03007
Author(s):  
Adam Razgonov ◽  
Anton Zhuravlyov ◽  
Kateryna Yashchuk ◽  
Vadym Shcheka
Keyword(s):  
Traffic Safety ◽  
Surface Membrane ◽  
Stable Operation ◽  
Shunt Resistance ◽  
Signaling Systems ◽  
Low Resistance ◽  
Rail Line ◽  
Track Circuits ◽  
Standard Value ◽  
Definition Of

The problems of electric track circuits calculating were investigated in the works of various authors, it is noted that there is no complete clarity on the definition of shunt resistance. The value of the calculated train shunt resistance in many respects affects the area of signaling systems rail channel stable operation and train traffic safety. It is relevant to study the possibilities of changing the standard value of and the conditions for the execution of track circuits shunt mode, especially for sections of railway with low resistance insulation of the rail line. The surface area of the “wheel-rail” skating, taking into account the different conditions of interaction dynamics and wear of rails and wheel elements were obtained in article. It is shown that the reduction of the normative value of the resistance of the train shunt is appropriate for signaling systems, especially for sections of railway with low resistance insulation of the rail line. An approximate estimate of the geometric parameters of the membrane that forms on the “wheel-rail” surface is obtained; proposed a more complete electrical replacing scheme for the train shunt circuit, which allows analyzing the influence of the circuit elements parameters values and the frequency of the signal current. A method for calculating the correlation dependence of the train shunt resistance from wheel-rail surface membrane parameters is proposed.

Analysis of Feedwater Pump Suction Pressure Decay Under Instant Turbine Load Rejection

1972 ◽  
Vol 94 (2) ◽  
pp. 83-88
Author(s):  
G. S. Liao ◽  
P. Leung
Keyword(s):  
Approximate Solutions ◽  
Maximum Load ◽  
Rate Of Change ◽  
Complete Analysis ◽  
Reliable Operation ◽  
Safe Operation ◽  
Suction System ◽  
Pressure Decay ◽  
Feedwater Pump ◽  
Regenerative Cycle

As steam-electric generating plant unit sizes increase, and as the capacities of the feedwater pumps increase, the design provision of an adequate suction for the safe operation of the feedwater pumps becomes increasingly important, especially when the pumps take suction from a deaerator within the regenerative cycle. The design provision of sufficient suction head for feedwater pumps operating under a maximum and stable turbine load is rather simple. However, the design of an adequate suction head to meet an instant turbine load rejection from maximum load is rather complex. It deals with the rate of pressure decay within the deaerator, mass of condensate stored, size of suction pipes, rate of change of condensate temperatures entering the deaerator, and numerous other transient parameters. Previously published literature [1–5] offers approximate solutions which assumed a constant temperature of condensate entering the deaerator during transient opertion under load rejection. Such an assumption generally results in an unnecessarily conservative design. Particularly, it may not be economically justifiable for very large units to be designed on that basis. This paper presents a complete analysis of this transient operating condition for the purpose of designing an economic optimum feedwater pump suction system for safe and reliable operation. Varying temperatures of the condensate entering the deaerator during transient operation are considered. Mathematic derivations augmented by numerical examples are included, to facilitate system design.

scholarly journals Methods of reception and synchronization of signals of automatic cab signalling

2021 ◽  
Vol 7 (2) ◽  
pp. 175-188
Author(s):  
V. V. Batraev ◽  
Keyword(s):  
Traffic Safety ◽  
Noise Immunity ◽  
Original Method ◽  
Rolling Stock ◽  
Railway Transport ◽  
Noise Emission ◽  
Discrete Information ◽  
Track Circuits ◽  
Objective Fact

The article discusses the problems of existing methods of receiving automatic cab signalling on railway transport, an original method of receiving and processing data is proposed. The need to solve the problems is due to the requirement of a qualitative improvement in the reliability of receiving codes, and as a consequence, the capacity of existing lines. First of all, this refers to a significant increase in the quality of reception and processing of information flows from rail lines. Today it is difficult to imagine the organization of the movement of rolling stock without relying on automatic block systems with secondary sealing of tonal track circuits by frequency modulation signals or automatic cab signaling without the use of multivalued automatic cab signaling with phase-difference modulation. Taking into account the objective fact of noise emission from the operation of energy-intensive railway equipment and modern locomotives, the issues of reliability and noise immunity of receiving discrete information (including signals of traditional automatic cab signaling) are becoming more and more urgent. Analysis of the reasons for the decrease in the reliability and noise immunity of railway automation and telemechanics systems, and, consequently, traffic safety also comes to the fore.

scholarly journals Mathematical Modeling of the Route of Logging Roads

2021 ◽  
pp. 150-161
Author(s):  
Anton Borovlev ◽  
◽  
Alexey Skrypnikov ◽  
Vyacheslav Kozlov ◽  
Tatyana Tyurikova ◽  
...  
Keyword(s):  
Traffic Safety ◽  
Transportation Network ◽  
Road Transport ◽  
Rate Of Change ◽  
Plane Curves ◽  
Flow Mode ◽  
Curvature Radius ◽  
Central Projections ◽  
The Road ◽  
Logging Roads

The implementation of tasks related to the development of the transportation network as a whole and logging roads as an integral part of it requires scientifically based theoretical studies of the patterns of formation of spatial curves when combining elements of the plan and the longitudinal profile, since the rational laying of the route for many years determines its most important transport and operational characteristics (speed, traffic safety, traffic capacity). Consideration of the visual perception of the road by the driver will improve the quality of design decisions, which will allow to avoid emergencies in the future after setting the route into service. On the other hand, a decrease in speed before seemingly sharp turns of the road affects the efficiency of logging road transport. Therefore, the view of the road ahead should strongly orient the driver, i.e. be visually clear and clearly changing, ensuring the constancy or smooth reduction of the traffic flow mode. At the same time, the need for a successful spatial solution of the road increases. In the designs of logging roads, straight lines, transition curves, described in recent years most often according to the clotoid, and circular curves are found as elements of the route plan. It is found that the road view in perspective correctly orients the driver of the car, i.e. it is visually clear, provided that the lines describing the edges of the roadway and the edges of the roadway in the perspective image are curved in the same direction as in the road plan. The purpose of the work is to determine a set of quantitative indicators (curvature, radius of the curve in the plan, maximum curvature, maximum rate of change of curvature) for optimization of the visual smoothness and clarity of the central projections of elementary spatial and plane curves. The performed studies allow us to fully characterize the visual smoothness and clarity of the central projections of elementary spatial and plane curves. The above algorithm makes it possible to compile a computer program to determine the mentioned indicators. The indicators determined by this algorithm allow us to evaluate both the visual smoothness and clarity of curves on logging roads.

Asymmetry of rail circuits with dsh-2 relay

2017 ◽  
pp. 280-297
Author(s):  
Alexander Manakov ◽  
Andrey Kabetskiy ◽  
Alexander Troshin ◽  
Yuriy Pashaev
Keyword(s):  
Spin Asymmetry ◽  
Practical Importance ◽  
Rolling Stock ◽  
Voltage Sags ◽  
Natural Experiments ◽  
Longitudinal Asymmetry ◽  
Rail Line ◽  
Track Circuits ◽  
The Impact ◽  
Line Resistance

Objective: To consider the causes and ways to reduce voltage sags on resonant track relays of track circuits with dssh-2 relays. Methods: Analysis of voltage depressions causes on a track relay with track circuit, free of rolling stock on rails, was carried out by means of natural experiments with oscillography and voltage on a track relay analysis, as well as measurement of insulation resistance of rail lines and the inductances of the main windings of transformers. Results: It was determined that one of the causes of voltage depressions on road relays were the transverse asymmetry of the resistance of rail lines caused by metal chips generated by pantograph trains when passing a nonoverlayable interval on the approach to the station. The impact of longitudinal spin asymmetry of rail line resistance on voltage sags, which is formed by a variation in inductance of the primary winding sections of an impedance bond. The relationship of voltage sags and the methods of rolling stock handling as well as places of electric power cut-offs’ was studied. Practical importance: The rule of connecting the main windings of transformers to the rails of sections was proposed, in order to reduce the impact of the variation in total inductance of transformers’ sections on the longitudinal asymmetry of rail line resistance. The conducted research made it possible to determine the causes and ways to reduce voltage dips on the resonant track relays of track circuits with dssh-2 relays.

Risk Attitudes and Behavior Among Norwegian Adolescents

2005 ◽  
Vol 10 (1) ◽  
pp. 25-38 ◽  
Author(s):  
Hilde Iversen ◽  
Torbjørn Rundmo ◽  
Hroar Klempe
Keyword(s):  
Public Health ◽  
Traffic Safety ◽  
Behavior Modification ◽  
Health Programs ◽  
Risk Attitudes ◽  
Community Based ◽  
Public Health Programs ◽  
The Core ◽  
And Behavior ◽  
Attitudes And Behavior

Abstract. The core aim of the present study is to compare the effects of a safety campaign and a behavior modification program on traffic safety. As is the case in community-based health promotion, the present study's approach of the attitude campaign was based on active participation of the group of recipients. One of the reasons why many attitude campaigns conducted previously have failed may be that they have been society-based public health programs. Both the interventions were carried out simultaneously among students aged 18-19 years in two Norwegian high schools (n = 342). At the first high school the intervention was behavior modification, at the second school a community-based attitude campaign was carried out. Baseline and posttest data on attitudes toward traffic safety and self-reported risk behavior were collected. The results showed that there was a significant total effect of the interventions although the effect depended on the type of intervention. There were significant differences in attitude and behavior only in the sample where the attitude campaign was carried out and no significant changes were found in the group of recipients of behavior modification.

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