Time Distribution Switch
AssigneeSchweitzer Engineering Laboratories, Inc.
InventorsDavid E. Whitehead, Shankar V. Achanta, Henry Loehner
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Abstract
Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.
Claims20
A method comprising:
- receiving, at a time distribution device, two or more consecutive time signals from each of a plurality of time sources;
- determining, for each time source, a duration between each of the two or more consecutive time signals, wherein the duration is based on an internal oscillator;
- comparing the duration between the two or more consecutive time signals for each time source to determine a time source with the lowest variation in the duration between the two or more consecutive time signals;
- selecting the time source with the lowest variation as a best available time source;
- and
- distributing the best available time source to one or more consuming devices.
A time distribution device comprising:
- a plurality of receivers configured to receive consecutive time signals from each of a plurality of corresponding precision time sources;
- an output configured to provide a precision time signal to an intelligent electronic device (IED), wherein the precision time signal is determined from a best available time source of the plurality of corresponding precision time sources;
- and
- a time quality module configured to:
- determine, for each of the plurality of precision time sources, a duration between two or more consecutive time signals, wherein the duration is based on an internal oscillator;
- compare the duration between the two or more consecutive time signals for each time source to determine a time source with the lowest variation in the duration between the two or more consecutive time signals;
- and
- select the precision time source with the lowest variation as the best available time source.
A non-transitory computer readable storage medium having instructions stored thereon, which when executed by a processor, cause the processor to perform a method for determining a best available time source, the method comprising:
- receiving, at a time distribution device, two or more consecutive time signals from each of a plurality of time sources;
- determining, for each time source, a duration between each of the two or more consecutive time signals, wherein the duration is based on an internal oscillator;
- comparing the duration between the two or more consecutive time signals for each time source to determine a time source with the lowest variation in the duration between the two or more consecutive time signals;
- and
- selecting the time source with the lowest variation as the best available time source.
Dependencies are inferred from the claim text.