RU2278046C1 - Track circuit - Google Patents

Abstract

FIELD: railway signaling and combustion.

SUBSTANCE: invention is designed to check conditions of rail lines in case of change of shunt conductance in wide range. Proposed device operates by determining difference in signals of two frequencies transmitted by rail line and determining condition of rail line bashing on value of difference in voltages.

EFFECT: includes reliability of checking condition of rail lines by processing of signals of lower and higher frequencies by one rectifier and introduction of compensating capacitor.

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Description

The invention relates to the field of railway automation and telemechanics, in particular to rail circuits of interval control systems for train traffic.

A known rail circuit containing frequency generators at the supply end connected to the rail line through supply transformers, and filters and receive relays are connected to the rail end of the rail end, the freedom of sections of the rail lines is controlled by the on state of the receiving relays [USSR Author's Certificate No. 187827, Cl. B 61 L 23/16, publ. in BI No. 21, 1966. Self-locking and automatic alarm device with rail circuits without insulating joints. Shishlyakov A.V., Putin D.K. and etc.].

The disadvantage of this device is the relatively small functionality limited by the use of a high-frequency signal current, at which, due to the inductive nature of the resistance of the rail lines, significant signal attenuation occurs at the relay end, and therefore, the rail lines of the block sections have a small length with a wide variation range conductivity insulation.

A rail circuit is known that contains frequency generators whose outputs are connected to the supply end of the rail line, and the first and second rectifiers are connected to the relay end through bandpass filters, the negative terminals of which and one of the plates of the first and second capacitors are combined. The positive leads of the rectifiers are connected to the front contacts of the control relay. Through the corresponding switching and rear contacts of the last plate of the first and second capacitors are connected to the winding of the track relay. The winding of the control relay receives power through the switching contact of the pendulum transmitter [RF Patent No. 2173277, IPC B 61 L 23/16, publ. BI No. 25, 2001. Rail chain. Tarasov E.M., Belonogov A.S., Kurov M.B.].

The disadvantage of this device is its low reliability, because the accuracy of determining the state of the rail line depends on the identity of the parameters of the signal rectifiers of lower and higher frequencies and the corresponding capacitors. In the case of changing the parameters of the capacitors, the state of the rail line is determined erroneously.

This technical solution is selected by the authors as a prototype.

The technical result is to increase the reliability of monitoring the state of rail lines by processing signals of lower and higher frequencies with one rectifier and the introduction of a compensating capacitor, which eliminates the disadvantages of the prototype.

The technical result is achieved by the fact that the rail circuit containing frequency generators, a power source, matching devices, two bandpass filters and a track relay is additionally equipped with a switching relay with a group of switching and normally closed contacts, a half-wave rectifier, a compensating capacitor, and some outputs of the strip outputs filters are combined and connected to one input terminal of a half-wave rectifier, the other input terminal of which is connected to the central contact of the switching barely, the right and left contacts of which are connected to other terminals of the outputs of the bandpass filters, the positive output of the half-wave rectifier is connected to one lining of the compensating capacitor, the other lining of which is connected to one terminal of the normally closed contact of the control relay and to one terminal of the winding relay relay, the other terminal of which connected to the negative output of a half-wave rectifier and to another terminal of the normally closed contact of the control relay.

Figure 1 presents the diagram of the rail chain;

figure 2, 3 and 4 are graphs of changes in the voltage at the output of the bandpass filters at frequencies of 25 and 50 Hz in the normal, shunt and control modes and the difference curves of the amplitudes (ΔU) of the voltages of lower (U _f1 ) and higher (U _f2 ) frequencies.

The rail circuit (Fig. 1) consists of a power source 1, generators of a lower frequency 2 and a higher frequency 3, matching devices 4, 5, bandpass filters of a low frequency 7 and a high frequency 8, a half-wave rectifier 9, a switching relay with a central 10 and normal closed 12 contacts, compensating capacitor 11, travel relay 13.

The operation of the device is as follows.

At the input of the rail circuit, the generators feed two frequencies with the same voltage levels. In the time interval t ₂ >t> t _{1, the} central contact 10 of the switching relay is pressed to the right contact, the contacts 12 are closed, and the rectified voltage of the higher frequency signal is supplied to the capacitor 11, which is being charged. In this interval, the track relay 13 is turned off due to shunting of the winding by the normally-closed contacts 12 of the switching relay.

In the time interval t ₃ >t> t _{2, the} central contact of the switching relay is switched to the left and pressed to the left contact, and the normally-closed contacts 12 open, thereby connecting the difference between the rectified voltage from the output of the band-pass filter 7 and the pre-charged capacitor 11.

Due to the inductive nature of the resistance of the rail line (z _p = r _p + ωL, where r _p is the active resistance of the rails, ωL is the inductive resistance), the voltage level at the output of the bandpass filter of a higher frequency (U _f2 ) 8 is less, and at the output of the filter the signal of a lower frequency (U _f1 ) 7 is more (figure 2-4). Due to this, in the interval t ₃ >t> t ₂ , the signal voltages U _f1 -U _f2 are subtracted and the track relay is switched on from the difference voltage of lower and higher frequencies.

An increase in the conductivity of the insulation of rail lines leads to a decrease in the amplitudes of the signals U _f1 and U _f2 (FIG. 2), and vice versa, with a decrease in the conductivity of the insulation, the voltages increase, provided that the voltage levels at the supply end of the rail line are equal. The change in the voltage difference ΔU = U _f1 -U _f2 , due to the proximity of the laws of variation of the voltages U _f1 and U _f2 from the insulation conductivity, is insignificant in the entire range of the conductivity change, and this ensures quasi-invariance to the change in insulation conductivity. The reaction of the voltage at the output of the bandpass filters 7 and 8 to the effects of the train shunt (figure 3) and the break of the rail line is different from the change in the conductivity of the insulation (figure 2). Firstly, in the shunt and control modes, the signal attenuates in the rail lines, as in the classical schemes of rail circuits, and secondly, the algorithm detuns, because voltage levels at different frequencies vary differently from the effects of a shunt or a break in the rail line, which is confirmed by the curves of FIGS. 3 and 4. This property guarantees the execution of the shunt and control modes.

The invariant properties of the proposed rail circuit are confirmed by the fact that the value of the fluctuation of the differential voltage in normal mode is

в диапазоне изменения проводимости изоляции от 0.02 до 10 см/км. В этом же диапазоне изменения проводимости изоляции колебание значения напряжения на частоте 25 Гц составляет

in the range of changes in the conductivity of insulation from 0.02 to 10 cm / km. In the same range of changes in the conductivity of the insulation, the voltage fluctuation at a frequency of 25 Hz is

and at a frequency of 50 Hz

The compact arrangement of the areas of the differential voltage ΔU in the normal, shunt and control modes allows you to guaranteedly perform all three modes. The minimum value of the differential voltage in the normal mode is 0.064 V, and the maximum value of the differential voltage in the shunt and control is 0.016 V. The safety factor for the execution of the modes is

In accordance with [Bryleev A.M., Kravtsov Yu.I., Shishlyakov A.F. Theory, structure and operation of rail chains. M .: Transport, 1978 (p. 388)] the minimum safety factor for the implementation of the modes is 1.2, therefore, the proposed rail chain allows you to perform modes with a three-fold margin.

Instruments widely used in railway automation can be used as an element base for implementation: frequency converters, bandpass filters, polarized relays with two groups of contacts, track relays, rectifiers, capacitors.

The proposed rail chain provides the following technical and economic advantages in comparison with the existing ones:

- functionality is expanded by ensuring quasi-invariance of up to 10 cm / km with a standard of 1 cm / km;

- increases the safety of train traffic by eliminating the possibility of the appearance of "false" freedom;

- the economic indicators of the transportation process are improved by reducing the downtime of trains at closed traffic lights due to the "false" employment of the rail line;

- improves the quality of service rail chains by increasing their reliability.

Claims (1)

A rail circuit containing frequency generators whose inputs are connected to a power source, outputs - through matching devices to the supply end of the rail line, two bandpass filters connected to the relay end of the rail line, and a track relay, characterized in that a switching relay with a group is additionally introduced switching and normally-closed contacts, a half-wave rectifier and a compensating capacitor, moreover, one output of the output of the bandpass filters is connected to one output of the input of a half-wave rectifier the other input terminal of which is connected to the central contact of the switching relay, its right and left contacts are connected to other outputs of the bandpass filters, the positive output of the half-wave rectifier is connected to one cover of the compensating capacitor, the other cover is connected to one terminal of the normally closed contact of the switching relay and to one terminal of the track relay winding, its other terminal is connected to the negative output of a half-wave rectifier and to the other terminal is normally closed of contact switching relay.

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