Voting Scheme for Time Alignment in Power Systems
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Solution Overview
Problem
In electric power transmission and distribution systems, time-stamped measurements from geographically isolated sources often arrive with unreliability due to independent time sources and varying communication path reliability, leading to invalid, delayed, or duplicate timestamps, which complicates the alignment of phasor data for precise monitoring and control tasks.
Innovation Solution
A voting scheme-based filter is employed by the phasor data concentrator to align time-stamped measurements, discarding out-of-sync data, establishing windows for acceptable timestamps, and using a voting scheme to determine a valid current time, ensuring accurate synchronization within nanoseconds for comparison and analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time-stamped measurements are collected from geographically isolated sources with independent time sources and varying communication paths, then the system can monitor and control power transmission, but the measurements become unreliable due to invalid, delayed, or duplicate timestamps
Solution Approach 1:
The system implements a feedback mechanism where received measurements are evaluated against expected time stamps, and feedback is provided to adjust the time alignment process. Measurements are compared against a expected time stamp derived from a reference clock, and those falling outside a tolerance window are identified and handled through the voting scheme to refine the time alignment.
Solution Approach 2:
A phasor data concentrator acts as an intermediary between distributed measurement sources and the final time-aligned data output. This intermediary collects measurements from multiple sources, applies the voting scheme to determine valid time stamps, and produces synchronized phasor data, thereby mediating the reliability and precision contradictions.
2Reliability
If a voting scheme is used to determine valid current time, then measurement reliability improves, but device complexity increases
Solution Approach 1:
The voting scheme applies partial action by evaluating only the necessary portions of received measurements against the current time window. Instead of processing every possible measurement indefinitely, the system uses a voting mechanism where a threshold number of valid votes within a time window suffices to confirm a time stamp's validity, reducing processing complexity while maintaining reliability.
3Measurement precision
If measurements are time aligned for nanosecond precision, then synchrophasor accuracy improves, but the complexity of synchronizing across geographically isolated sources increases
Solution Approach 1:
The time alignment process is segmented into discrete steps: collecting measurements with timestamps, evaluating each against expected time stamps, applying the voting scheme to determine valid times, and producing aligned phasor data. This segmentation breaks down the complex synchronization task into manageable operations that can be processed sequentially.
Data Source
AI summary
Systems and methods for time aligning time-stamped measurements using a voting scheme are disclosed. The system and method filter incoming measurements based on whether the time-stamped measurements fall within a defined time window. In response to determining that the time stamp falls within the defined time window, the time-stamped measurement is added to a time slice corresponding with the time stamp. In response to determining that the time-stamped measurement does not fall within the defined time window, the time window is re-established based on a voting scheme.