IED Time Synchronization Handover to Prevent Protection Blockage
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Solution Overview
Problem
Inaccurate synchronization between intelligent electronic devices (IEDs) in a digital substation can lead to blocking of protective functions, resulting in unintentional power supply interruptions due to phase differences and incorrect impedance calculations.
Innovation Solution
Implement a method that sends a pre-synchronization message when the grandmaster role switches between time units, informing IEDs about the previous synchronization source, ensuring continuous synchronization and preventing functional blockages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the grandmaster role switches between time units to maintain synchronization redundancy, then reliability is improved, but IEDs may experience functional blockage due to unrecognized synchronization source changes
Solution Approach 1:
The system performs preliminary actions by notifying IEDs about the upcoming grandmaster role switch before the actual switch occurs. This advance notification allows IEDs to prepare for the synchronization source change, preventing functional blockage while maintaining the reliability benefits of role switching between time units.
Solution Approach 2:
The system implements feedback by monitoring the synchronization state and detecting when a grandmaster role switch occurs. This feedback mechanism triggers the notification process to IEDs, ensuring they are aware of the synchronization source change and can adjust their operation accordingly to avoid functional blockage.
2Measurement precision
If IEDs verify the identity of the synchronization source to ensure accuracy, then measurement precision is improved, but this verification process can cause functional blockage when the source changes
Solution Approach 1:
The system performs preliminary notification about the grandmaster role switch before the actual change occurs. This allows IEDs to verify the new synchronization source's identity in advance and recognize it as valid, maintaining measurement precision while avoiding functional blockage that would occur during source transitions.
3Reliability
If multiple redundant synchronization sources are used to maintain protection functionality, then reliability is improved, but device complexity increases
Solution Approach 1:
The system uses an intermediary notification mechanism that mediates between multiple redundant synchronization sources and IEDs. This intermediary approach allows the system to maintain multiple sources for reliability while simplifying the interaction complexity by providing a standardized notification process that IEDs can follow regardless of which source becomes active.
Data Source
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AI summary
The invention relates to a method for avoiding functional blockages of intelligent electronic devices (IEDs) (2, 4) that are connected to each other as part of a local network (1) and via the locally limited network (1), wherein the locally limited network (1) has at least two time reference units (3). The method according to the invention comprises the following steps: (1) One of the time reference units (3a) assumes an active grandmaster role as a synchronization source. (2) All other time reference units (3b, 3c) remain in their slave state and synchronize with the time reference unit (3a) in the grandmaster role.(3) When one of the time units (3b, 3c) in slave mode switches to the role of the grandmaster time unit, a pre-synchronization message (8) informs all IEDs (2, 4) in the local network (1) via the network (1) whether, and if so, with which previous grandmaster time unit (3a), the current grandmaster time unit (3c) was synchronized. This prevents the function of the IEDs (2, 4) that generate or process data streams whose samples were acquired synchronously with the previous grandmaster time unit from being blocked.