Method, system, and software code for calibration of rail track circuits, and related rail track circuit

Patent metadata

Field	Value
Publication number	US-11148690-B2
Application number	US-201916367936-A
Country	US
Kind code	B2
Filing date	Mar 28, 2019
Priority date	Mar 28, 2019
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

Method, system and software code for calibrating a rail track circuit comprising a plurality of rails coupled to form a track section having a predefined length, a transmit processing unit coupled to the track section at a first end of the track section, and a receive processing unit coupled at the second end of the track section. A transfer function between a transmit voltage applied by the transmit processing unit at the track section and a resulting receive current detected at the receive processing unit is first determined and then applied to the rail track circuit for automatic initial calibration or recalibration.

First claim

What is claimed is:

1. A method for calibrating a rail track circuit, said rail track circuit comprising:
a plurality of rails coupled to form a track section having a predefined length,
a transmit processing unit coupled to the track section at a first end of the track section, and
a receive processing unit coupled to the track section at a second end of the track section,
wherein the method comprises:
determining a transfer function between a transmit voltage applied by the transmit processing unit at said first end of the track section and a resulting receive current detected at said second end by the receive processing unit; and
calibrating the rail track circuit by applying the determined transfer function to the rail track circuit, and

wherein the determining of the transfer function further comprises selecting or calculating one or more variables suitable to influence the values of the resulting receive current detected by the receive processing unit, the selected or calculated variables including one or more of a resistance selected from the group consisting of a rail electrical resistance (R r ) of the track section, a ballast electrical resistance (R r ) of the track section, an electrical resistance (R stx ) of an energy source of the transmit processing unit, and an electrical resistance (R srx ) of an energy source of the receive processing unit.

2. The method for according to claim 1 , wherein the determining of the transfer function further comprises determining one or more coefficients applicable to values of the corresponding selected or calculated variables.

3. The method according to claim 2 , wherein the determining of one or more coefficients comprises:
calculating at least one corrective coefficient (parR r ) suitable to be applied to values of the rail electrical resistance (R r ) of the track section; and/or
calculating at least one corrective coefficient (parR b ) suitable to be applied to values of the ballast electrical resistance (R b ) of the track section; and/or
calculating at least one corrective coefficient (parR stx ) suitable to be applied to values of the electrical resistance (R stx ) of the energy source of the transmit processing unit; and/or
calculating at least one corrective coefficient (parR srx ) suitable to be applied to values of the electrical resistance (R srx ) of the energy source of the receive processing unit.

4. The method according to claim 1 , wherein the transfer function is determined by the following equation:

I
rx

=

constant
+

parRb
⁢

⁢

1
·

R
b

parRb
⁢

⁢
2

+

R
b

+

parRr
·

R
r

+

parRs
tx

Rs
tx

⁢

parRs
rx

Rs
rx

wherein (I rx ) is the receive current detected by the receive processing unit resulting from a predefined value of the transmit voltage applied by the transmit processing unit, (R b ) is the ballast electrical resistance of the track section and (parR b1 ) and (par R b2 ) are a first coefficient and a second coefficient, respectively, suitable to be applied to values of the ballast electrical resistance, (R r ) is a rail electrical resistance of the track section and (parR r ) is a corrective coefficient suitable to be applied to values of the rail electrical resistance (R r ), (R stx ) is an electrical resistance of an energy source of the transmit processing unit and (parR stx ) is a corrective coefficient suitable to be applied to values of the electrical resistance of the energy source of the transmit processing unit, (R srx ) is the electrical resistance of an energy source of the receive processing unit and (parR srx ) is a corrective coefficient suitable to be applied to values of the electrical resistance of the energy source of the receive processing unit.

5. The method according to claim 1 , wherein calibrating the rail track circuit comprises:
calculating actual values for one or more of a resistance selected from the group consisting of the ballast electrical resistance (R b ) of the rail track circuit, the rail electrical resistance of the track section (R r ), and the electrical resistances (R stx , R srx ) of the energy source of the transmit processing unit and of the receive processing unit, respectively, and
calibrating the rail track circuit by using the determined transfer function based on the actual values calculated for the one or more of the resistances selected from the group consisting of ballast electrical resistance (R b ) of the track circuit, the rail electrical resistance of the track section (R r ), and the electrical resistances (R stx , R srx ) of the energy source of the transmit processing unit and of the receive processing unit, respectively.

6. The method according to claim 1 , wherein calibrating the rail track section comprises adjusting, based on the determined transfer function, a first predefined threshold of the rail track circuit, and wherein the presence or absence of a railway vehicle on the track section is determined based on the first predefined threshold.

7. The method according to claim 6 , wherein during calibrating the rail track section, the first predefined threshold is adjusted based on a value of the receive current determined via said determined transfer function.

8. The method according to claim 7 , wherein calibrating the rail track section comprises comparing said value of the receive current determined via the determined transfer function with a value of the receive current measured at the receive processing unit and if the difference between the value of the receive current determined and the value of the receive current measured is above a second predetermined threshold, then generating an alarm, otherwise adjusting the value of said first threshold and/or of a gain of the transmit processing unit based on the value of said difference between the value of the receive current determined and the value of the receive current measured.

9. The method according to claim 1 , wherein calibrating the rail track section comprises

Assignees

• Alstom Transp Tech

Inventors

• Fries Jeffrey
• Mijatovic Nenad

Classifications

• B61L1/20 Primary

  Safety arrangements for preventing or indicating malfunction of the device, e.g. by leakage current, by lightning · CPC title

• B61L25/025

  Absolute localisation, e.g. providing geodetic coordinates · CPC title

• B61L29/22

  electrically · CPC title

• B61L23/04

  for monitoring the mechanical state of the route · CPC title

• B61L1/188 Primary

  Use of coded current · CPC title