Time signal propagation delay correction

• US 9,270,442 B2
• Filed: 04/29/2014
• Issued: 02/23/2016
• Est. Priority Date: 04/29/2014
• Status: Active Grant

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: Schweitzer Engineering Laboratories, Incorporated
• Inventors: Rice, Raymond W., Achanta, Srinivas
• Primary Examiner(s): Guarino, Rahel
• Application Number:
  US14/264,394
• Publication Number:
  US 20150312023A1
• Time in Patent Office: 665 Days
• Field of Search: 455/63.1, 455/67.16, 375/354, 375/371, 375/257, 375/355, 375/357, 375/358, 375/360, 370/350
• US Class Current: 1/1
• CPC Class Codes: H04J 3/0635 Clock or time synchronisation in a network timer in protocols H04L69/28
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04L 7/0041 Delay of data signal

Abstract

Disclosed herein are a variety of systems and methods for correcting for propagation delay in time signals used in connection with an electric power generation and delivery system. According to various embodiments, a device consistent with the present disclosure may determine an estimated propagation delay between an accurate time source and a receiving device. The propagation delay may be determined based on a variety of transmission parameters including, for example, communication channel type and/or length. A corrected time signal may be generated by advancing a reference incitation such as an “on-time” reference and/or “start-of-second” reference included in the time signal by an amount associated with the propagation delay. The corrected time signal may then be transmitted to the receiving device.

Claims

1. A device associated with an electric power delivery system, the device comprising:

an interface configured to receive a time signal from an accurate time source;

a processor communicatively coupled to the interface;

a computer-readable storage medium communicatively coupled to the processor, the computer-readable storage medium storing instructions that when executed by the processor cause the processor to;

determine a first estimated propagation delay between the accurate time source and a first receiving device,

generate a first corrected time signal by advancing a plurality of signal edges associated with encoded time information following a reference indication included in the time signal by the first estimated propagation delay, wherein the reference indication comprises an on-time reference rising signal edge indication, and

transmit the first corrected time signal to the first receiving device.

2. The device of claim 1, wherein the time signal comprises a inter-range instrumentation group encoded time signal.

3. The device of claim 1, wherein the reference indication comprises an indication denoting a start of a data frame of the time signal compromising encoded time information.

4. The device of claim 1, wherein the time signal comprises a time signal generated using a reference atomic clock.

5. The device of claim 1, where determining the first estimated propagation delay between the accurate time source and the first receiving device is based on one or more transmission parameters associated with a communication channel between the accurate time source and the first receiving device.

6. The device of claim 5, wherein the one or more transmission parameters comprise one or more of a communication channel length, a communication channel type, and an ambient temperature.

7. The device of claim 5, wherein the one or more transmission parameters are provided to the device by user input.

8. The device of claim 1, wherein the instructions are further configured to cause the processor to:

determine a second estimated propagation delay between the accurate time source and a second receiving device;

generate a second corrected time signal by advancing a reference indication included in the time signal by the second estimated propagation delay; and

transmit the second corrected time signal to the second receiving device.

9. The device of claim 1, wherein the first estimated propagation delay comprises an estimated amount of propagation delay having previously occurred in the time signal prior to being received by the interface.

10. The device of claim 1, wherein the first estimated propagation delay comprises an estimated amount of anticipated propagation delay between the accurate time source and the first receiving device.

11. A method for generating a corrected time signal in an electric power delivery system comprising:

receiving a time signal from an accurate time source;

determining a first estimated propagation delay between the accurate time source and a first receiving device;

generating a first corrected time signal by advancing signal edges associated with encoded time information following a reference indication included in the time signal by the first estimated propagation delay, wherein the reference indication comprises an on-time reference rising signal edge indication; and

transmitting the first corrected time signal to the first receiving device.

12. The method of claim 11, wherein the time signal comprises a inter-range instrumentation group encoded time signal.

13. The method of claim 11, wherein the reference indication comprises an indication denoting a start of a data frame of the time signal compromising encoded time information.

14. The method of claim 11, wherein the common time signal comprises a time signal generated using a reference atomic clock.

15. The method of claim 11, where determining the first estimated propagation delay between the accurate time source and the first receiving device is based on one or more transmission parameters associated with a communication channel between the accurate time source and the first receiving device.

16. The method of claim 15, wherein the one or more transmission parameters comprise one or more of a communication channel length, a communication channel type, and an ambient temperature.

17. The method of claim 15, wherein the one or more transmission parameters are provided by user input.

18. The method of claim 11, wherein the method further comprises:

determining a second estimated propagation delay between the accurate time source and a second receiving device;

generating a second corrected common time signal by advancing a reference indication included in the common time signal by the second estimated propagation delay; and

transmitting the second corrected common time signal to the second receiving device.

19. The method of claim 11, wherein the first estimated propagation delay comprises an estimated amount of propagation delay having previously occurred in the time signal prior to being received from the accurate time source.

20. The device of claim 11, wherein the first estimated propagation delay comprises an estimated amount of anticipated propagation delay between the accurate time source and the first receiving device.

21. A device associated with an electric power delivery system, the device comprising:

an interface configured to receive an inter-range instrumentation group encoded time signal from an accurate time source;

a processor communicatively coupled to the interface;

a computer-readable storage medium communicatively coupled to the processor, the computer-readable storage medium storing instructions that when executed by the processor cause the processor to;

determine a first estimated propagation delay between the accurate time source and a first receiving device based on a length and a type of a communication channel between the accurate time source and the first receiving device,

generate a first corrected time signal by advancing an on-time reference indication included in the time signal by the first estimated propagation delay and advancing a plurality of signal edges associated with encoded time information following the on-time reference indication, by the first estimated propagation delay,

transmit the first corrected time signal to the first receiving device

determine a second estimated propagation delay between the accurate time source and a second receiving device;

generate a second corrected time signal by advancing a reference indication included in the time signal by the second estimated propagation delay; and

transmit the second corrected time signal to the second receiving device.