Precision Time Source Failure Detection in Power Systems
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Solution Overview
Problem
Precision time sources in electric power transmission and distribution systems are susceptible to failures due to factors like spoofing, jamming, and limited accuracy of protocols such as NTP and SNTP, which can impact the reliability of time synchronization for critical applications like synchrophasor calculations.
Innovation Solution
A system and method for detecting failures in precision time sources, utilizing a time quality module to compare multiple time signals and select the best available time source, with features like holdover periods and local time source monitoring to ensure continuous accurate time reference distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single precision time source is used for time synchronization, then the system structure is simple, but the reliability deteriorates when the time source fails or is spoofed
Solution Approach 1:
The patent implements independent monitoring of the primary time source using a separate monitoring channel that does not rely on the primary source itself. This local quality approach ensures that the monitoring function has different reliability characteristics than the time source being monitored, allowing detection of failures including spoofing attacks without adding significant system complexity.
Solution Approach 2:
The patent introduces an intermediary monitoring mechanism that compares the primary time source against alternative time sources or expected time characteristics. This intermediary layer detects anomalies such as spoofing or jamming without requiring a complete redundant time source system, thus improving reliability while maintaining relatively simple system structure.
2Reliability
If multiple time sources are monitored and compared, then the reliability improves, but the device complexity increases
Solution Approach 1:
The patent monitors multiple time sources or time characteristics but only fully processes and switches to alternatives when actual failure or anomaly is detected. During normal operation, the system maintains simple single-source functionality while having alternative sources ready for comparison, thus improving reliability without proportionally increasing complexity under all operating conditions.
Solution Approach 2:
The patent divides the time source monitoring function into separate independent modules: primary time source reception, alternative time source monitoring, comparison logic, and switching control. This segmentation allows each module to remain simple while the collective system provides robust multi-source monitoring and failure detection capabilities.
3Reliability
If time source failure detection is implemented, then the reliability improves, but the difficulty of detecting and measuring increases due to spoofing and jamming
Solution Approach 1:
The patent implements preliminary monitoring and validation of time source signals before they are fully trusted or used for critical synchronization. By continuously checking time source characteristics against expected parameters and alternative sources in advance, the system can detect spoofing or jamming attempts before they cause synchronization failures, thus improving reliability while managing detection complexity through proactive rather than reactive measures.
Data Source
AI summary
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.