Track circuit protection system

Abstract

The present invention provides a track circuit protection system, the system includes a choke transformer, an air-core coil, a tuning and matching unit, and a compensation tuning unit, wherein the choke transformer includes a choke coil and two lead terminals, and the choke transformer is connected to two tracks through its two lead terminals respectively; the air-core coil includes a choke coil and two lead terminals, and the air-core coil is connected to the two tracks through its two lead terminals respectively; the tuning and matching unit is connected to both ends of the air-core coil; the compensation tuning unit includes an oscillation branch and a capacitance branch connected in parallel, and the compensation tuning unit is connected between the two tracks. The track circuit protection system of the present invention can effectively eliminate the crosstalk interference of adjacent sections after a mechanical insulation joint is damaged, and can greatly reduce the influence of the high-frequency components in the traction current on the track circuit monitoring, thereby ensuring the operational safety of the railway system.

Description

Technical Field

[0001] The invention belongs to the technical field of rail transportation, and in particular relates to a track circuit protection system. Background Art

[0002] At present, audio track circuits are generally used in railway stations. The track circuit signal is an FSK signal, which contains locomotive signal information that can be recognized by locomotive onboard equipment. Mechanical insulation joints are used in the station to divide the track circuit sections in the station. When a mechanical insulation joint is damaged, the track circuits in adjacent sections will be transmitted across zones. When the amplitude of the cross-zone signal meets the receiving threshold of the onboard equipment, it will cause the onboard equipment to operate. In severe cases, the locomotive signal upgrade display will appear, seriously endangering the safety of railway operations.

[0003] Since the track circuit relies on the rails as a transmission path, and the rails are the locomotive current discharge path, when the traction current returning to the substation through the rails contains high-frequency components, it will be connected to the track circuit receiving end after passing through the track circuit receiving end, forming an interference signal, causing the track circuit monitoring curve to change, affecting the judgment and normal work of the maintenance unit, and also increasing the maintenance workload. Summary of the invention

[0004] In view of the above problems, the present invention provides a track circuit protection system.

[0005] A track circuit protection system, the system comprises a choke transformer, an air-core coil, a tuning and matching unit, and a compensation tuning unit, wherein:

[0006] The choke transformer comprises a choke coil and two lead terminals, and the choke transformer is connected to two tracks through the two lead terminals respectively;

[0007] The hollow coil comprises a choke coil and two lead terminals, and the hollow coil is connected to the two tracks through the two lead terminals respectively;

[0008] The tuning and matching unit is connected to both ends of the air-core coil;

[0009] The compensation tuning unit comprises an oscillation branch and a capacitance branch connected in parallel, and the compensation tuning unit is connected between the two tracks.

[0010] Furthermore, the choke transformer also includes an iron core, an adaptor coil, and an adapter and a circuit breaker that form a loop with the adaptor coil.

[0011] Furthermore, the tuning and matching unit includes a tuning part and a matching part.

[0012] Furthermore, the choke transformer is connected to the two rails via lead terminals using equal-resistance steel-clad copper rail lead wires.

[0013] Further,

[0014] The matching part includes a transformer, a first compensation inductor and a second compensation inductor, a first electrolytic capacitor and a second electrolytic capacitor;

[0015] The first electrolytic capacitor and the second electrolytic capacitor are respectively connected to two ends of the first coil of the transformer;

[0016] The first compensation inductor and the second compensation inductor are respectively connected to two ends of the second coil of the matching transformer.

[0017] Furthermore, the tuning and matching unit is connected to the air-core coil by a wire.

[0018] Furthermore, the hollow coil is connected to the two rails via a connecting terminal using a steel-clad copper rail lead wire.

[0019] Furthermore, the oscillation branch includes a first capacitor and an inductor connected in series; and the capacitor branch includes a second capacitor.

[0020] Furthermore, the compensation tuning unit is connected to the rail via a connecting terminal using a steel-clad copper rail lead wire.

[0021] The track circuit protection system of the present invention can effectively eliminate the crosstalk interference of adjacent sections after a mechanical insulation joint failure, and can significantly reduce the impact of high-frequency components in the traction current on track circuit monitoring, thereby ensuring the operational safety of the railway system. Other features and advantages of the present invention will be described in the subsequent description, and partly become apparent from the description, or can be understood by implementing the present invention. The objects and other advantages of the present invention can be achieved and obtained by the structures indicated in the description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A simplified schematic diagram of a track circuit protection system according to an embodiment of the present invention is shown;

[0024] Figure 2 A circuit structure schematic diagram of a choke transformer according to an embodiment of the present invention is shown;

[0025] Figure 3 A circuit structure schematic diagram of a tuning and matching unit according to an embodiment of the present invention is shown;

[0026] Figure 4 A circuit structure principle diagram of a compensation tuning unit according to an embodiment of the present invention is shown;

[0027] Figure 5 It shows a signal cross-zone and protection principle diagram of a track circuit protection system according to an embodiment of the present invention;

[0028] Figure 6 It shows the protection principle diagram when the rail return current in the track circuit without protection device is unbalanced and contains high-frequency harmonic components;

[0029] Figure 7 A protection principle diagram of a track circuit protection system according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The track circuit protection system of the present invention comprises a choke transformer BE, an air-core coil SVA, a tuning and matching unit PT, and a compensation tuning unit TB. Figure 1 As shown, the track circuit system of the present invention is arranged in a section in the track circuit, and the transformer BE, the air-core coil SVA, and the compensation tuning unit TB are connected across two tracks in the section, and the tuning matching unit PT is connected across the air-core coil SVA.

[0032] The main function of the choke transformer BE in the track circuit protection system of the present invention is to conduct the traction current so that it can smoothly pass through the mechanical insulation node and return to the substation. Figure 2 Two choke transformers of the track circuit protection system of the present invention are shown. Figure 2 The left side is an air-choke transformer, including a choke and an iron core, wherein the choke has three lead terminals 1-3. The air-choke transformer is connected to the rail through the choke lead terminal 1 and the lead terminal 2, and the lead terminal 3 can be connected to the lead terminal 3 of the choke of the choke transformer in the adjacent section, wherein the choke transformer BE can be connected to the rail through the lead terminal using an equal-resistance steel-clad copper rail lead wire. Figure 2The right side of the figure shows a choke adapter transformer, including a choke, an iron core, an adapter coil, an adapter, and a circuit breaker Rd, wherein the choke is the same as the choke in the above-mentioned air-choke transformer. In order to protect the choke transformer, a box is also provided outside the choke transformer.

[0033] The choke transformer BE of the present invention presents high impedance to the audio track circuit signal, and conducts the industrial frequency traction current through the choke coil and the lead-out terminal 1 and the lead-out terminal 2; the industrial frequency series resonance is formed by the adapter coil and the adapter, and low impedance is transformed to the rail side, thereby reducing the industrial frequency voltage on the rail side; the audio track circuit signal parallel resonance is formed by the adapter coil and the adapter, and high impedance is transformed to the rail side, without consuming audio signal energy.

[0034] The hollow coil SVA of the track circuit protection system of the present invention comprises a choke coil, a lead terminal, and a box body for protecting the hollow coil SVA.

[0035] The hollow coil SVA provides a stable inductance for the tuning part of the tuning matching unit to generate parallel resonance, and can present low impedance to the high-frequency harmonics in the traction current, and form a short-circuit effect on the high-frequency components, effectively reducing the high-frequency voltage formed on the rail side by the rail surface voltage formed by the high-frequency harmonics, which will effectively reduce the interference to the track circuit monitoring equipment. The hollow coil SVA can be connected to the rail through the lead-out terminal using a steel-clad copper rail lead wire.

[0036] The tuning and matching unit PT of the track circuit protection system of the present invention is composed of a tuning part and a matching part. Figure 3 The circuit structure diagram of the tuning and matching unit PT is shown in FIG. Figure 3 The tuning part shown includes an oscillation branch (a circuit consisting of an inductor TL1 and a capacitor C3 connected in series with the inductor TL1) and a capacitor branch (a circuit consisting of a capacitor C4 and a capacitor C5 connected in parallel with the capacitor C4), and the oscillation branch is connected in parallel with the capacitor branch. The oscillation branch forms a series resonance with the frequency signal of the track circuit in the adjacent section, and the resonant impedance approaches zero, forming a "zero impedance", realizing the first line of protection for the adjacent signal. The oscillation branch is connected in parallel with the capacitor branch, forming a parallel resonance with the hollow coil, forming a "polar impedance", which meets the transmission of the frequency signal of the track circuit in this section.

[0037] The matching part in the tuning and matching unit PT includes a transformer AFT, two compensation inductors PTL, and two electrolytic capacitors C1 and C2. The two electrolytic capacitors C1 and C2 are respectively connected to the two ends of the first coil of the transformer AFT, and the two compensation inductors PTL are respectively connected to the two ends of the second coil of the matching transformer. The matching part realizes the matching transmission of the signal between the rail and the cable through the connection terminals E1 and E2. The tuning and matching unit PT is connected to the hollow coil SVA through the U1 copper plate terminal and the U2 copper plate terminal by a wire. The hollow coil SVA and the tuning and matching unit PT constitute the working part of the track circuit, and form the first line of protection for the track circuit signal of the adjacent section, forming a higher impedance to the track circuit signal frequency.

[0038] The compensation tuning unit TB of the track circuit protection system of the present invention comprises an oscillation branch and a capacitance branch connected in parallel with the oscillation branch. Figure 4 The circuit structure diagram of the compensation tuning unit is shown in FIG. Figure 4 As shown, the oscillation branch includes a capacitor C and an inductor L connected in series with the capacitor C, and the capacitor branch includes a capacitor C0. The oscillation branch forms a series resonance with the frequency signal of the track circuit of the adjacent section, and the resonant impedance approaches zero, forming a "zero impedance" to achieve a second line of protection for the adjacent signal. The capacitor branch is connected in parallel with the oscillation branch, so that the compensation tuning unit TB is equivalent to a 25uF capacitor at the frequency of the track circuit of this section, compensating for the inductance of the rails in this section, so that the signal of this section is matched and transmitted.

[0039] The compensation tuning unit TB is connected to the rails by using a steel-clad copper rail lead wire, presenting a 25uF compensation capacitor characteristic to the track circuit signal of the current section and a low impedance to the track circuit signal of the adjacent section.

[0040] Usually, after the mechanical insulation joints of adjacent sections of the train track are damaged (such as Figure 5 The insulation joint between 8DG and 1G is damaged), and the track circuit signal of the adjacent section forms a channel through the connected insulation joint, rail, occupied wheelset, and the center point of the choke transformer at both ends of the insulation joint, forming an out-of-zone signal current. A signal current is formed on the rail in front of the occupied wheelset and is received by the locomotive signal induction coil. When the out-of-zone signal current exceeds the specified value, it causes the on-board equipment to operate, and then causes the locomotive signal to display an error, which in severe cases causes the locomotive signal to upgrade.

[0041] Figure 5 The signal crossing zone and protection principle diagram of the track circuit protection system of the present invention are shown. Figure 5As shown in FIG. 1 , the tuning part in the tuning matching unit PT and the compensation tuning unit TB of the track circuit protection system of the present invention respectively form a double protection for the track circuit signal. When the 1G is equipped with such a protection unit of the present invention, due to the tuning function of the tuning part in the tuning matching unit PT, a short circuit can be formed for the cross-zone signal (such as Figure 5 The solid line with arrows in the figure shows the direction of the signal current at 1700 Hz, which greatly reduces the magnitude of the cross-zone signal current in the rail. When the tuning part in the tuning matching unit PT fails, the tuning part in the compensation tuning unit TB (i.e., the tuning circuit composed of capacitor C, inductor L and capacitor C0) can play the same role, forming a secondary short circuit for the cross-zone signal (such as Figure 5 This effectively provides short-circuit protection for the cross-zone signal current formed after the mechanical insulation joint is damaged, so that the on-board equipment will not receive the cross-zone signal, ensuring the normal operation of the vehicle.

[0042] like Figure 6 The protection principle diagram of the track circuit protection system according to the present invention is shown when the rail return current is unbalanced and contains high-frequency harmonic components. Figure 6 As shown in Figure 2, when the rail return current is unbalanced and contains high-frequency harmonic components (i.e. Figure 6 (When the medium current I1≠I2), since the air choke transformer and matching transformer have no filtering function and present a large impedance to the high-frequency signal, a high voltage U will be generated on the receiving rail, which will be transmitted to the receiving end, affecting the normal operation of the monitoring equipment at the receiving end. When using protective devices, such as Figure 7 As shown, the hollow coil can present a lower impedance to the high-frequency signal, and can clamp the voltage of the high-frequency signal at the receiving end tuning and matching unit at a lower level, thus playing a protective role.

[0043] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A track circuit protection system, the system comprising a choke transformer, an air-core coil, a tuning and matching unit, and a compensation tuning unit, wherein: The hollow coil comprises a choke coil and two lead terminals, and the hollow coil is connected to two tracks through the two lead terminals respectively; The tuning and matching unit is connected to both ends of the air-core coil; The compensation tuning unit comprises an oscillation branch and a capacitance branch connected in parallel, and the compensation tuning unit is connected between the two tracks; The choke transformer comprises a choke coil and an iron core, wherein the choke coil has three lead terminals 1-3; the choke transformer is connected to the rail through the choke coil lead terminal 1 and the lead terminal 2, and the lead terminal 3 is connected to the lead terminal 3 of the choke coil of the choke transformer in the adjacent section; The tuning and matching unit PT is connected to the U1 copper plate terminal and the U2 copper plate terminal by a wire. The hollow coil SVA is connected; the hollow coil SVA and the tuning and matching unit PT constitute the working part of the track circuit and form the first line of protection for the track circuit signal of the adjacent section; Provide short-circuit protection for the cross-zone signal current generated after the mechanical insulation joint is damaged, so that the on-board equipment will not receive the cross-zone signal; The compensation tuning unit includes an oscillation branch and a capacitance branch connected in parallel with the oscillation branch. The oscillation branch includes a capacitor C and an inductor L connected in series with the capacitor C. The capacitance branch includes a capacitor C0. The oscillation branch forms a series resonance with the frequency signal of the track circuit of the adjacent section. The resonant impedance approaches zero, forming a zero impedance, and realizing the second protection of the adjacent signal. The capacitance branch is connected in parallel with the oscillation branch, so that the compensation tuning unit is equivalent to a 25uF capacitor at the frequency of the track circuit of this section, compensating for the inductance of the rails of this section, so that the signal of this section is matched and transmitted; The choke transformer also includes an iron core, an adaptor coil, and an adapter and a circuit breaker forming a loop with the adaptor coil; The choke transformer is connected to the two rails through lead terminals using an equal-resistance steel-clad copper rail lead wire; the matching part includes a transformer, a first compensation inductor and a second compensation inductor, a first electrolytic capacitor and a second electrolytic capacitor; the first electrolytic capacitor and the second electrolytic capacitor are respectively connected to the two ends of the first coil of the transformer; the first compensation inductor and the second compensation inductor are respectively connected to the two ends of the second coil of the matching transformer.

2. The track circuit protection system according to claim 1, wherein: The tuning and matching unit includes a tuning part and a matching part.

3. The track circuit protection system according to claim 1, wherein: The tuning and matching unit is connected to the air-core coil by a conducting wire.

4. The track circuit protection system according to claim 1, wherein: The hollow coil is connected to the two rails through a connecting terminal using a steel-clad copper rail lead wire.

5. The track circuit protection system according to claim 1, wherein: The oscillation branch includes a first capacitor and an inductor connected in series; and the capacitor branch includes a second capacitor.

6. The track circuit protection system according to claim 1 or 5, wherein: The compensation tuning unit is connected to the rail by a steel-clad copper rail lead wire through a connecting terminal.

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