Measurement Unit Placement for Pseudo-Measurement-Free Grid Estimation
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Solution Overview
Problem
The challenge in power distribution grids is determining an optimal placement of measurement units to accurately estimate the state of the grid while minimizing costs, as extensive deployment is costly and pseudo-measurements introduce uncertainty, especially in non-convex problems with limited historical data.
Innovation Solution
A two-stage method combining Minimum Norm and Weighted Least Square state estimation, which ensures accurate capture of line congestions and voltage profiles without pseudo-measurements, by iteratively optimizing measurement unit placement and deploying them in a way that minimizes the number of units required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement units are extensively deployed in the grid, then the accuracy of state estimation is improved, but the cost of deployment increases significantly
Solution Approach 1:
The patent changes the parameter of measurement unit placement from random or uniform distribution to optimized placement based on grid topology and state estimation requirements. By solving an optimization problem that determines the optimal set of nodes for measurement unit deployment, the system achieves high estimation accuracy with fewer units. The optimization considers grid parameters such as node connectivity, line impedances, and measurement redundancy to identify the minimal set of strategic locations.
2Ease of operation
If pseudo-measurements are used to offset lack of real measurements, then the state estimation can proceed, but uncertainty in estimation accuracy increases
Solution Approach 1:
The patent extracts and removes pseudo-measurements from the state estimation process, relying exclusively on real measurements from strategically placed measurement units. By eliminating pseudo-measurements (which are forecasts or projections based on historical data), the system avoids the uncertainty and non-Gaussian nature of such data. The optimization of measurement unit placement ensures sufficient real measurements are obtained to perform accurate state estimation without needing to supplement with unreliable pseudo-measured data.
3Measurement precision
If measurement units are placed to capture voltage phase angle differences, then the accuracy of state estimation is improved, but the cost increases due to the need for high-precision devices
Solution Approach 1:
The patent applies local quality by placing measurement units at specific locations in the grid where they provide maximum information value for state estimation. Rather than uniformly distributing high-precision devices throughout the grid, the optimization identifies specific nodes where measurements are most critical for determining voltage phase angles and overall grid state. This localized strategic placement reduces the total number of high-cost devices needed while maintaining estimation accuracy.
Data Source
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Figure 3A~3B
AI summary
The invention relates to a method for determining an optimal placement of measurement units for estimating the state of a physical power distribution grid. The method comprises a step of searching for measurement-unit placements that are compatible with a State Estimation method that is performed in two stages, first, a Minimum Norm formulation, followed by a Weighted Least Square one.