Synchrophasor Data Recovery for Missing PMU Measurements
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Solution Overview
Problem
Current methods for recovering missing phasor measurement unit (PMU) measurements, such as Nuclear Norm Minimization and Hankel Norm Minimization, are inadequate as they fail to accurately determine temporally missing data and are computationally costly due to high resource requirements.
Innovation Solution
A method and system that utilize a Total Variation (TV) algorithm in conjunction with a nuclear norm minimization algorithm to determine substitute entries for missing PMU measurements by analyzing differences in PMU data sets, allowing for the recovery of both temporally and randomly missing data with reduced computational intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Nuclear Norm Minimization is used to recover missing PMU measurements, then randomized missing data can be determined, but temporally missing data cannot be determined
Solution Approach 1:
The patent combines Nuclear Norm Minimization with Total Variation Minimization into a hybrid algorithm. The Nuclear Norm component handles randomized missing data by minimizing the nuclear norm of the data matrix, while the Total Variation component handles temporally missing data by minimizing the temporal variation of the recovered values. This merging allows the system to recover both types of missing data effectively.
Solution Approach 2:
The recovery algorithm is constructed as a composite method integrating two different mathematical approaches: Nuclear Norm Minimization (which assumes low-rank structure) and Total Variation Minimization (which assumes piecewise smooth temporal behavior). This composite algorithm leverages the strengths of both methods to handle diverse missing data patterns that neither method could address alone.
2Adaptability or versatility
If Hankel Norm Minimization is used to recover missing PMU measurements, then both randomized and temporally missing data can be determined, but computational and processing resources are excessively high
Solution Approach 1:
The patent employs computationally efficient algorithms (Nuclear Norm Minimization and Total Variation Minimization) that require significantly less computational power and processing time compared to Hankel Norm Minimization. These lighter-weight algorithms achieve acceptable recovery performance without the excessive resource demands of Hankel Norm methods, making them suitable for real-time or near-real-time PMU data recovery applications.
Solution Approach 2:
The patent changes the mathematical parameters and objective functions used in the recovery process. Instead of using Hankel Norm (which involves complex matrix operations and high computational complexity), the patent uses Nuclear Norm and Total Variation parameters that lead to more computationally tractable optimization problems with lower resource requirements while maintaining recovery effectiveness.
3Loss of information
If existing recovery methods are used, then some missing measurements can be recovered, but the computational complexity and processing time are excessive for real-time applications
Solution Approach 1:
The patent segments the recovery process into distinct components: one segment handles randomized missing data using Nuclear Norm Minimization, while another segment handles temporally missing data using Total Variation Minimization. This segmentation allows each component to be optimized independently and processed more efficiently, reducing overall computational time compared to a monolithic approach like Hankel Norm Minimization.
Data Source
AI summary
A method for recovering missing phase measurement unit (PMU) measurements from a plurality of PMUs is provided. The method comprises: receiving a plurality of obtained PMU measurements from the plurality of PMUs; populating a PMU dataset based on the plurality of obtained PMU measurements; determining a plurality of missing entries within the PMU dataset, wherein each of the plurality of missing entries indicates a missing PMU measurement within the PMU dataset at a particular time; determining a plurality of substitute entries for the plurality of missing entries based on an optimization algorithm that determines differences associated with a missing entry, of the plurality of missing entries, and a first set of PMU measurements, of the plurality of obtained PMU measurements, that are taken immediately prior to the missing entry; and inserting the plurality of substitute entries into the PMU dataset to generate a new PMU dataset.


