Frequency Measurement Synchronization for Inaccurate Asset Clocks
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Solution Overview
Problem
Existing demand response systems face challenges in integrating smaller energy assets with less accurate clocks, as they struggle to meet the strict timing requirements for frequency and voltage measurements, which can significantly impact the accuracy of reported frequency values.
Innovation Solution
A method and system for determining a synchronization offset by receiving measurement data from multiple sources, calculating correlation measures for different time shift values, and selecting the time shift value that indicates the strongest correlation to correct the timing information in measurement data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If smaller energy assets with less accurate clocks are integrated into demand response systems, then the quantity of energy assets and system flexibility increase, but the measurement precision and timing accuracy deteriorate
Solution Approach 1:
The patent introduces a synchronization offset as an intermediary parameter that mediates between the inaccurate local clocks of smaller energy assets and the centralized time reference. By calculating and applying this offset, the system enables integration of assets with less accurate clocks without compromising overall measurement precision, thus resolving the contradiction between increasing asset quantity and maintaining timing accuracy.
Solution Approach 2:
The patent changes the timing parameter by introducing a synchronization offset that corrects the absolute time stamps from smaller energy assets. This parameter transformation allows the system to accept data from assets with less accurate clocks while maintaining the required timing precision for frequency measurements, thereby enabling greater asset integration without sacrificing measurement quality.
2Measurement precision
If very accurate local clocks are installed on each asset to meet timing requirements, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
Instead of requiring each asset to have inherently accurate clocks, the patent introduces a synchronization offset as a mediator that corrects timing errors post-measurement. This approach maintains measurement precision without imposing complex and expensive accurate clock requirements on individual assets, thereby reducing device complexity while preserving timing accuracy.
Solution Approach 2:
The patent creates a corrected version of the time stamp by applying the synchronization offset, effectively producing an accurate time reference without requiring the original measurement device to have high clock accuracy. This copying approach allows precise timing to be achieved through data processing rather than through expensive hardware requirements.
3Ease of operation
If absolute time stamps from smaller energy assets are used directly, then the ease of operation and integration simplify, but the measurement precision and frequency accuracy deteriorate
Solution Approach 1:
The synchronization offset serves as an intermediary correction mechanism that maintains the simplicity of integrating smaller energy assets while compensating for their timing inaccuracies. By applying this offset to the absolute time stamps, the system preserves ease of integration without sacrificing frequency measurement precision, thus resolving the contradiction between operational simplicity and measurement accuracy.
Data Source
AI summary
Disclosed is a method of determining a synchronization offset for measurement data relating to an electrical power supply network. First and second data sets of measurement data are received from a first source and a second source. Each data set includes measurements of an electrical parameter of the network measured at the respective source together with time information indicating measurement times of the measurements. Correlation measures are determined for each of a plurality of time shift values, indicating correlation between a first set of measurement values derived from the first data set and a second set of measurement values derived from the second data set, with one of the first and second sets of measurement values being derived under application of a time shift corresponding to the respective time shift value. One of the time shift values is selected in dependence on the correlation measures and used to provide a synchronization offset. The synchronization offset is used to correct time information in measurement data from one of the sources.


