RU2328400C1 - Track circuit - Google Patents

Abstract

FIELD: automation.

SUBSTANCE: invention concerns railway automation and can be applied in the systems of interval regulation of underground trains. The track circuit consists of a rail way, two track transformers, power generator and a receiver. One end of the rail way is linked to the secondary coil of the transformer, the primary coil of which is connected to the power generator with functional superimposing of automated locomotive signalling coding, and the other end is linked to the secondary coil of the second track transformer, the primary coil of which is connected to the track receiver with functional superimposing of automated locomotive signalling coding. Capacitors are connected in series to the secondary coils of track transformers. Values of capacitors satisfy the conditions of voltage resonance in the track circuit at the carrier frequency of track control signal in normal mode and of inverse resonance at the carrier frequency of automated locomotive signalling.

EFFECT: significant decrease of effect of traction current asymmetry; improved noise immunity and reliability of track circuit operation.

3 dwg

Description

The invention relates to railway automation and can be used in interval control systems for metro trains.

A device according to patent No. 2173648 C. B61L 23/16, containing a generator, isolation transformers, filters, resistors, AND logic, phase meters, an amplifier, two comparators, two time delay units, an NAND logic element, a multiplexer, a trigger, a contact directional relay and a frequency divider. The disadvantage of this device is the instability of the rail circuit with a reduced ballast resistance due to the interference effect of the asymmetry of the traction current.

The closest in technical essence to the claimed invention is a device for protecting rail chains according to patent No. 2173275 C. B61L 23/16, adopted as a prototype.

The known device contains a rail line, to the two ends of which are connected matching elements in the form of track transformers. A generator in the form of a power source, automatic locomotive signaling coding devices are connected to a matching element at one end of the rail line. A track receiver in the form of a track relay and an automatic locomotive alarm coding device are connected to a matching element at the other end of the rail line. The generator through a track transformer connected to it supplies a signal to the rail line. At the receiving end, through a track transformer, the signal enters the track receiver with a track coding device for automatic locomotive signaling. If the current voltage is lower than the threshold, then the section is busy, otherwise it is free. When the rail circuit is occupied, an automatic locomotive signal is sent under the train.

The disadvantage of this device is the instability of the rail circuit due to the interference effect of the asymmetry of the traction current.

The task of the invention is to increase the noise immunity and reliability of the rail chain.

The technical result achieved by the implementation of the invention is expressed in a significant reduction in the interference effect of the asymmetry of the traction current.

The technical result is achieved by the fact that the rail circuit contains a rail line, to one end of which a secondary winding of the first track transformer is connected, the primary winding of which is connected to a generator with functional coding of the automatic locomotive signaling, and the secondary winding of the second track transformer is connected to the other end of the rail line the primary winding of which is connected to the track receiver with a functional overlay coding automatic locomotive alarm system, is additionally equipped with first and second capacitors, the first capacitor is connected in series with the secondary winding of the first track transformer, the second capacitor is connected in series with the secondary winding of the second track transformer, and the capacitance values of the capacitors satisfy the resonance conditions of the voltage in the rail circuit at the carrier frequency of the rail control signal in normal mode and current resonance at the carrier frequency of the automatic locomotive signal in place the location of the train shunt at the time of occupation of the rail chain of maximum length.

Figure 1 presents a General view of the rail circuit, which includes a generator with functional coding of automatic locomotive signaling 1, a receiver with functional coding of automatic locomotive alarm 2, the first track transformer T1, the second track transformer T2, the rail line 3, the first capacitor C 1 , the second capacitor C2.

The rail chain operates as follows.

The electric signal for monitoring the rail line (RRL) from the generator 1 passes through the track transformer T1, through the capacitor C1 and enters the rail line 3. After passing the rail line 3, the signal through the capacitor C2 and the track transformer T2 enters the receiver 2. In the case of the integrity of the rail line 3 and the absence of a shunt, the signal level at the receiver is above the busy threshold, the rail circuit is considered free (normal mode). Fulfillment of the condition of voltage resonance at the frequency of the KRL signal in this mode by appropriate selection of the capacitance of the capacitors provides a maximum of the KRL signal with suppression of side frequencies. The resulting filtering of the KRL signal at the carrier frequency increases the noise immunity of the rail circuit.

As the train approaches, due to shunting, the signal level at the receiver decreases and falls below the occupancy threshold. The rail chain is considered busy. After occupying the rail circuit, a signal for automatic locomotive signaling (ALS) is supplied to the rail line for train reception. The quality of the transmission path is a rail circuit - the train is characterized by the shape of the amplitude-frequency characteristic and the current level of the ALS signal in the rails in the immediate vicinity of the train shunt (under the train coils). At the time of occupation of the rail circuit, the ALS current is minimal. The longer the rail circuit, the lower the ALS current. Consequently, the transmission path is a rail chain - a train is unstable, as a rule, on the longest rail chains at the time of their occupation. In this case, at the location of the train shunt, there is a current resonance at a frequency that is advisable to use as the carrier frequency of the automatic locomotive signal. The condition of current resonance at the frequency of the ALS signal provides the maximum signal ALS with suppression of side frequencies. The resulting filtering of the ALS signal at the carrier frequency increases the noise immunity of the rail circuit in the ALS encoding mode.

The constant component of the asymmetry of the traction current through the secondary windings of the path transformers is absent due to the inclusion of capacitors in series with them. Therefore, the stability of the rail circuit is ensured by the exclusion of the demagnetization of the track transformers of the constant component of the asymmetry of the traction current and the resonant filtering of the signals KRL and ALS.

The rail chain can be implemented within the framework of the “Motion” system (Kuznetsov SV and others, “The“ Motion ”system: stationary equipment, a central post and a single radio communication system. Modern Automation Technologies, 2001, No. 2). A feature of the operation of the rail circuits of the Motion system is the relatively high carrier frequencies of the rail line monitoring signal - 4262 Hz, and the coding signal of the automatic locomotive signaling system - 3348 Hz. As capacitors, you can use a wide class of capacitors with a capacity of 10 ÷ 70 μF. As path transformers, transformers with a transformation coefficient of 40 can be used. As a generator and receiver with functional overlapping of the coding of automatic locomotive signaling, a device similar to the transceiver of the AB-UE system can be used (I.V. Belyakov et al., “Microprocessor-based unified system of automatic blocking AB-UE ”, Automation, Communications and Computer Science, 2002, No. 6).

The amplitude-frequency characteristic of the rail circuit in the normal mode has the form shown in figure 2. The maximum characteristic is at point A at a frequency of 4.26 kHz.

The amplitude-frequency characteristic of the ALS signal current in the rails near the train shunt of the longest rail circuit at the time of its occupation is presented in Fig.3. The maximum characteristic is at point B at a frequency of 3.35 kHz.

Analysis of the amplitude-frequency characteristics (figure 2, figure 3) shows that the exclusion of the constant component and a significant attenuation of the decaying frequency harmonic components of 300 Hz, 600 Hz, 900 Hz, 1200 Hz, etc. asymmetries of the traction current ensures reliable operation of the rail circuit and stable transmission of ALS signals to the train.

Thus, the introduction of the first and second capacitors eliminates the magnetization of the track transformer of the constant component of the traction current asymmetry, significantly reduces the influence of the first harmonics of the traction current asymmetry, and improves the noise immunity of the rail circuit, which increases the reliability of the rail circuit.

Claims (1)

A rail circuit comprising a rail line, to one end of which a secondary winding of the first track transformer is connected, the primary winding of which is connected to a generator with functional coding of the automatic locomotive signaling, a secondary winding of the second track transformer, the primary winding of which is connected to the track, is connected to the other end of the rail line receiver with functional coding of automatic locomotive signaling, characterized in that the rail chain l is equipped with the first and second capacitors, the first capacitor is connected in series with the secondary winding of the first track transformer, the second capacitor is connected in series with the secondary winding of the second track transformer, and the capacitance values of the capacitors satisfy the resonance conditions of the voltage in the rail circuit at the carrier frequency of the rail control signal in normal mode and current resonance at the carrier frequency of the automatic locomotive signal at the location of the train shunt in moment of occupation of the rail chain of maximum length.

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