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17
Aripov Nazirjon Mukaramovich, doctor, of Technical Sciences, professor, of the Department "Automatics and telemechanics
in railway transport" Tashkent Institute of Railway Transport Engineering Rikhsiev Dilmurod Hodzhiakbarovich, deputy dean, ".Faculty on organization of transportation and transport logistics" Tashkent Institute of Railway Transport Engineering E-mail: dilmurod.rikhsiev@gmail.com
IMPROVEMENTS TO THE STATION TRACK CIRCUITS OF RAILWAY AUTOMATION AND REMOTE CONTROL SYSTEMS
Abstract: The article deals with the improvement of station rail circuits of railway automation and telemechanics systems. To improve the noise immunity of the rail circuit, it is proposed to preserve the existing phase method of protecting the track receiver from interference from the adjacent rail circuit and to add a pulse mode to protect it from external sources of interference.
Keywords: rail circuit, relay, interference, impulse, phase, analyzer, track receiver, safety.
Introduction pulse mode to protect it from external sources of interference.
Rail chains in the system of railway automation and telem- Using a pulse-phase analyzer as a path receiver in station rail echanics are sensors of information about where the rolling circuits, it is possible to significantly reduce the risk of danger-
stock is located within the station or the distances. Among the other elements in the rail automation and telemechanics system, rail chains are the most important, since they directly determine the safety of train traffic. Rail chains provide operational control and monitoring by railway traffic at stations and sections by using continuously received information on the status of each block-section, which makes it possible to monitor the trains without the need for their visual observation [1].
On railways, the conditions of rail chains become more unfavorable (ballast contamination and increase in its conductivity, the state of insulating joints, rail connectors). The main methods of protection against interference of station rail circuits include the phase protection principles with the use of opposite phases of adjacent rail circuits. The application of phase noise protection has its own problems, from neighboring rail chains, the influence of wandering currents. In the two-element sectorial plug-in (DSS) relay, there are the following disadvantages: relatively small contact resource (100.000 operations); the influence of temperature on the characteristics of the relay is great; jamming the sector with the plates of the "swollen" core. Taking into account the above, it will be expedient to search for other methods of protection and improvement of station rail circuits [2-3].
Main part
In station rail circuits, noise immunity can be improved by retaining the phase method of protecting the track receiver from interference from the adjacent rail circuit and adding a
ous failures of station rail circuits (see Fig. 1-2.).
To increase the safety of station rail circuits, a model of a pulse-phase path receiver is proposed in (Fig. 3). From a sound generator, a voltage with an amplitude of 10 V equivalent to a rectangular pulse at a threshold of the sensitivity of a phase-frequency analyzer of approximately 0.55 V is applied to the input of an PPhA. The voltage of a local source U0 with a frequency f = 50 Hz is taken 5.2V (nominal for operating conditions). In parallel to the winding of the IRR relay, a digital voltmeter is switched on in the manual start mode. The integrating properties of the voltmeter are set approximately 250 ms.
At fixed values of the frequency of the sound generator fn, the voltages on the IRR winding were repeatedly counted using a digital voltmeter. In this case, for fn = f0, fn > f0 + 50 Hz and fn < f0 - 25 Hz, the results of multiple samples coincided. At the frequency intervals fn from 25 to 50 Hz and from 50 to 100 Hz, oscillations of the measurement results caused by infra-low frequencies in the vicinity of f0 were observed. The obtained experimental function uap =y( fn, f0) (Fig. 5) confirms the results of theoretical calculations in the neighborhood of f0 and for multiple T /T . The voltage levels on the IRR winding turned out to be lower than the calculated ones, since the influence of the voltage drop across the transistors VT1, VT2 and the diodes VD1, VD2 of the PPhA block, as well as the rectifier bridge diodes built into the IRR relay case, was not taken into account in the calculation.
Figure 1. General scheme of the pulse-phase analyzer (PPhA)Where, PPA - pulse power analyzer relay; IRR - pulse converter with rectifier attachment reed switch relay;IF - impulse phase relay
Figure 2. Structural diagram of the pulse-phase analyzer I Un\
Generator PPhA IRR Digital voltmeter
U„ Ucp
Figure 3. Model of a pulse-phase track receiver
The band of frequency selection of the pulse-phase analyzer depends on the integrating properties of the track receiver. The measurements are performed directly on the IRR winding and do not take into account the voltage drop across the diodes of the IRR rectifier bridge. If, for example, the relay has a trigger threshold of 2.0V, then the selection band for the pulse-phase analyzer for this relay will be between 46 and 54 Hz (see Figure 5). In other words, at interference frequencies below 46 and above 54 Hz, the pulse-phase track relay does not respond to interference, regardless of their amplitude.
The circuit of the pulse-phase analyzer is protected from a dangerous failure by the fact that in the event of damage to its elements, the pulse-phase track receiver passes from the state of impulse operation to the protective state "permanently on" or "permanently off". As a result of this, the states of the contacts of the PPA relay and the IF relay are violated during their dynamic operation when receiving a signal from the rail circuit, and the signal at the output of the dynamic conjunctor disappears.
Ucp,V
ft Calculated
Experimental
20 30 40 50 60 70 80
f, Hz
Figure 4. The dependence of the average voltage on the frequency
The idealization of the characteristics of diodes and transistors adopted in the calculations is justified, since the absolute value of the voltage level does not influence the conclusions about the frequency properties of the pulsephase analyzer.
The phase-amplitude characteristic of a pulse-phase track receiver obtained experimentally and is shown in (Fig 6). A distinctive positive feature of this characteristic from the analogous characteristic of the TSP relay is the independence of
Un, B
the phase sensitivity angle from the amplitude of the signal from the rail circuit. The influence of the spread of the gains of transistors on the results of experimental studies is negligible.
Phase sensitivity of the pulse-phase analyzer within certain limits depends on the amplitude of the voltage of the reference signal u0 and unop on the threshold of operation of the pulse-phase track receiver. If necessary, the phase sensitivity angle of the pulse-phase path receiver can be controlled by changing the reference signal level u0.
-35—
w
ч Ê
V
V ///
—Jt-
-+20C
Ф,град
Figure 5. Amplitude-phase characteristic of a pulse-phase track receiver
Conclusions
The proposed pulse-phase analyzer meets the requirements for the equipment of railway automation and telemechanics used in floor-standing devices. The width of the amplitude-phase characteristic when the ambient temperature varies from minus 60 °C to plus 60 °C and the value of the local voltage UM = 5.5 V, which corresponds to the nominal value of the voltage on the pulse relay type IRR included at the output of the unit. If the value of the track voltage Un is more than 10V, the phase sensitivity zone does not change. The phaseamplitude characteristic of the proposed track receiver shows
the independence of the phase sensitivity angle from the amplitude of the signal from the rail circuit. This means that the oscillations of the detuning angle, caused in practice by changing the external conditions, do not lead to a general detuning of the impulse-phase track receiver under consideration. As a positive factor, we also note a slight effect of temperature on the phase-amplitude characteristic. The solution obtained is relevant for encoding information with automatic locomotive signaling, and in a pulse-phase rail circuit, a sound property is a means of ensuring the safety of train traffic.
References:
1. Kostrominov A. M., Rikhsiev D. Kh. Theoretical analysis of the frequency properties of a pulse - phase receiver. Izvestiya, St. Petersburg: PGUPS,- 2011.-No. 3.- P. 181-190.
2. Kostrominov A. M., Rikhsiev D. Kh. Protection of the receiver of rail circuits from interference by means of a pulse-phase analyzer / Transport of the Russian Federation.- St. Petersburg: PGUPS,- 2011.- No. 5 (36).- P. 68-70.
3. Aripov N. M., Rikhsiev D. Kh. Analysis of station rail circuits in railway automation and telemechanics systems / Bulletin of Tashkent TashIIT,- 2017.- No. 1.- P. 80-84.
