Time Signal Verification Device for Power Network Synchronization
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Solution Overview
Problem
Current precision time signal distribution systems in power networks face challenges with accuracy beyond the millisecond range, particularly due to limitations in protocols like NTP and SNTP, and are susceptible to malicious attacks and spoofing, which affect the reliability of time synchronization for critical applications such as synchrophasor calculations.
Innovation Solution
A system and method for verifying and distributing precision time signals using a time distribution device that receives multiple time sources, determines the best available time signal, and switches to a holdover period using local oscillators when primary sources fail, incorporating protocols like IEEE 1588 and GNSS for enhanced accuracy and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If NTP and SNTP protocols are used for time distribution, then ease of operation is improved, but measurement precision deteriorates (cannot achieve accuracy beyond millisecond range)
Solution Approach 1:
The system segments the time distribution function by introducing an intermediate time distribution device between the primary time source and consuming devices. This device receives time signals from multiple sources, verifies their accuracy, and distributes the verified time signal, thereby achieving high-precision synchronization while maintaining operational simplicity through standardized protocol interfaces.
2Reliability
If multiple time sources are verified and switched between, then reliability is improved, but device complexity increases
Solution Approach 1:
The time distribution device performs preliminary verification of multiple time sources before distribution, checking their accuracy and validity in advance. It maintains a pool of verified time sources and switches between them based on verification results, ensuring reliability while managing complexity through pre-validation and automated switching logic.
Solution Approach 2:
The time distribution device acts as an intermediary between primary time sources and consuming devices, verifying time signals from multiple sources and distributing only verified accurate time signals. This intermediary function isolates consuming devices from the complexity of multiple source management while ensuring reliability through verification.
3Reliability
If holdover period with local oscillators is used when primary sources fail, then reliability is maintained, but measurement precision deteriorates
Solution Approach 1:
The system prepares for potential primary source failures by maintaining a pool of pre-verified alternative time sources. When the primary source fails, the system can immediately switch to a verified alternative source rather than entering holdover mode, thus maintaining both reliability and precision. The verification mechanism cushions against the precision loss that would otherwise occur during holdover periods.
Data Source
AI summary
The time signal verification and distribution device disclosed herein verifies and distributes a time signal to consuming devices. The device determines a time quality status of a first and second time signal, calculates a difference between a first and a second time signal, and compares the difference to a predetermined threshold. Based on the time quality status and the comparison, the time signal verification and distribution device distributes a time signal to a plurality of time signal consuming devices. Exceeding the predetermined threshold may indicate a spoofing attack or other problem with the time signals.