Verification of time sources

• US 10,527,732 B2
• Filed: 02/09/2017
• Issued: 01/07/2020
• Est. Priority Date: 02/09/2017
• Status: Active Grant

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: Schweitzer Engineering Laboratories, Incorporated
• Inventors: Sagen, Eric A., Zeller, Mark L., Kasztenny, Bogdan Z.
• Primary Examiner(s): Nguyen, Chuong P
• Application Number:
  US15/429,013
• Publication Number:
  US 20180224558A1
• Time in Patent Office: 1,062 Days
• Field of Search: 3423574, 34235722, 34235739
• CPC Class Codes: G01S 19/01 Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
• CPC Class Codes: G01S 19/03 Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/39 the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
• CPC Class Codes: G04F 1/005 using electronic timing, e.g. counting means pulse time delay arrangements H03K5/13; modifications of electronic switches for introducing a time delay before switching H03K17/28
• CPC Class Codes: G04R 20/10 Tuning or receiving; Circuits therefor
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 13/00022 using wireless data transmission
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/18 using switches, relays or circuit breakers, e.g. intelligent electronic devices [IED]
• CPC Class Codes: Y04S 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• CPC Class Codes: Y04S 40/126 using wireless data transmission

Abstract

This disclosure relates to systems and methods for verification of time sources. In various embodiments, one or more secondary time sources may be used to verify the accuracy of a primary time source prior to relying on a time signal created by the primary time source. In one embodiment, a first interface is configured to receive the primary time signal from a primary time source, and a second interface in communication with a secondary time source is configured to receive a secondary time signal. A time assessment subsystem is configured to determine an occurrence of a verification criteria. Upon the occurrence of the verification criteria, the system may compare the primary time signal and the secondary time signal to determine whether that the primary time signal is consistent with the secondary time signal. If the signal is consistent, the primary time source may be utilized by the system.

Claims

1. An intelligent electronic device (IED) operable to monitor electrical conditions in an electric power system and to utilize an external time source, the IED comprising:

a Global Navigation Satellite Systems (GNSS) receiver configured to receive a primary time signal;

an internal oscillator configured to generate a secondary time signal;

a time assessment subsystem configured to;

determine an occurrence of a verification criteria;

perform a comparison of the primary time signal and the secondary time signal to determine that the primary time signal is consistent with the secondary time signal;

verify the primary time signal based on the comparison; and

a time utilization component configured to utilize a plurality of measurements of electrical conditions associated with a corresponding plurality of time measurements based on the primary time signal to perform at least one operation after the time assessment subsystem has verified the primary time signal and to block a protective action on the electric power system based on the primary time signal when a failure to verify the primary time signal occurs.

2. The system of claim 1, wherein the GNSS receiver is configured to receive a time quality indicator associated with the primary time signal, and wherein the time assessment subsystem is configured to verify the quality of the primary time signal independent of the time quality indicator.

3. The system of claim 1, wherein the verification criteria comprises one of a disruption in receipt of the primary time signal, a start of the system, and a pre-established schedule.

4. A system configured to verify and utilize a primary time signal, the system comprising:

a first interface configured to receive the primary time signal from a primary time source;

a second interface in communication with a secondary time source and configured to receive a secondary time signal;

a time assessment subsystem configured to;

determine an occurrence of a verification criteria;

perform a comparison of the primary time signal and the secondary time signal to determine that the primary time signal is consistent with the secondary time signal; and

verify the primary time signal based on the comparison; and

a time utilization component configured to utilize the primary time signal to perform at least one operation after the time assessment subsystem has verified the primary time signal and to block a protective action on the electric power system based on the primary time signal when a failure to verify the primary time signal occurs.

5. The system of claim 4, wherein the first interface is configured to receive a time quality indicator with the primary time signal, wherein the verification criteria of the time assessment subsystem is independent of the time quality indicator communicated with the primary time signal.

6. The system of claim 5, wherein the time quality indicator comprises a time quality flag under a C37.118 standard.

7. The system of claim 4, wherein the verification criteria comprises a disruption in receipt of the primary time signal.

8. The system of claim 4, wherein the verification criteria comprises a start of the system.

9. The system of claim 4, wherein the time assessment subsystem is further configured to generate an archive comprising a representation of at least one metric associated with the primary time source, and the comparison further comprises a comparison based on the at least one metric.

10. The system of claim 4, wherein the time assessment subsystem is further configured to generate an archive comprising a representation of at least one metric associated with the secondary time source, and the comparison further comprises a comparison based on the at least one metric.

11. The system of claim 4, wherein the time utilization component comprises a sensor component and the operation comprises associating a measurement of an electrical condition with a time stamp based on the primary time signal.

12. The system of claim 4, wherein the time utilization component comprises a monitored equipment interface and the operation comprises associating one of a control instruction and a status indicator with a time stamp based on the primary time signal.

13. The system of claim 4, wherein the first interface comprises a Global Navigation Satellite Systems (GNSS) receiver.

14. The system of claim 13, wherein the second interface comprises a network communications interface and the secondary time signal is provided to the network communications interface using an IEEE 1588 standard.

15. The system of claim 4, further comprising a reporting subsystem configured to generate an indication of a failure to verify the primary time signal based on the comparison.

16. A method for verifying and utilizing a primary time signal, the method comprising:

receiving, via one or more processors of an intelligent electronic device (IED), the primary time signal from a primary time source using a first interface;

receiving, via the one or more processors, a secondary time signal from a secondary time source using a second interface;

determining, via the one or more processors, an occurrence of a verification criteria;

performing, via the one or more processors, a comparison of the primary time signal and the secondary time signal and determining that the primary time signal is inconsistent with the secondary time signal;

determining, via the one or more processors, that the primary time signal is not verified based on the comparison; and

blocking, via the one or more processors, the IED from performing at least one operation upon failing to verify the primary time signal.

17. The method of claim 16, comprising:

receiving, via the one or more processors, a time quality indicator communicated with the primary time signal; and

determining, via the one or more processors, that the primary time signal is not verified independent of the time quality indicator.

18. The method of claim 16, further comprising:

generating, via the one or more processors, an archive comprising a representation of at least one metric associated with the primary time source; and

wherein comparing the primary time signal and the secondary time signal further comprises comparing the at least one metric to the primary time source.

19. The method of claim 16, wherein the primary time source comprises a GNSS system.

20. The method of claim 16, wherein utilizing the primary time signal to perform at least one operation after verifying the primary time signal comprises associating one of a control instruction and a status indicator with a time stamp based on the primary time signal.

21. The method of claim 16, wherein utilizing the primary time signal to perform at least one operation after verifying the primary time signal comprises associating a measurement of an electrical condition with a time stamp based on the primary time signal.