Node-Level Power System Inertia Estimation via Multi-Innovation Identification
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Solution Overview
Problem
Existing methods for estimating power system inertia focus on overall and regional levels, lacking precision in reflecting the specific spatial distribution and failing to identify low-inertia regions effectively, which hampers operational dispatch and stability.
Innovation Solution
A method utilizing time-series data from synchronized phasor measurement units, preprocessing, and multi-innovation identification to construct an output error moving average model, analyzing node inertia, frequency, and injection power, and solving for unknown parameters to estimate spatial distribution of inertia at a node level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods (equivalent inertia, polynomial fitting, system identification) are used to estimate power system inertia, then the estimation can be performed at system and region levels, but the precision is limited and the specific spatial distribution of inertia cannot be reflected
Solution Approach 1:
The patent segments the power system into multiple nodes and estimates inertia for each node individually rather than treating the system as a whole or in large regions. This is achieved by constructing separate output error moving average models for each node and using multi-innovation identification to solve for node-specific inertia parameters, thereby revealing the detailed spatial distribution of inertia across the power system.
Solution Approach 2:
The patent transitions from traditional system-level or regional-level inertia estimation to node-level estimation, adding a spatial dimension to the measurement. By estimating inertia at each node and mapping these values to their corresponding geographic locations, the patent creates a two-dimensional spatial distribution map of inertia across the power system, enabling identification of low-inertia regions that were previously invisible.
2Adaptability or versatility
If non-synchronous power supplies (DC and renewable energy) are integrated into the grid, then the transmission power is decoupled from grid frequency, but the overall inertia level is greatly attenuated and frequency stability deteriorates
Solution Approach 1:
The patent applies local quality by identifying specific nodes or regions with low inertia characteristics caused by high penetration of non-synchronous power supplies. Rather than treating the entire system uniformly, the method pinpoints localized areas where inertia is deficient and can target these regions for specific reinforcement measures such as adding synchronous condensers or adjusting generator dispatch to maintain frequency stability.
3Productivity
If centralized grid-connected region of renewable energy is developed, then new energy integration is improved, but the region exhibits obvious low-inertia characteristic contrasting with high-inertia synchronous generator regions
Solution Approach 1:
The patent segments the power system into nodes with different inertia characteristics, allowing distinct identification of renewable energy centralized regions with low inertia versus synchronous generator regions with high inertia. This segmentation enables precise characterization of inertia distribution patterns and supports differentiated operational strategies for different regions.
4Power
If high-capacity DC transmission line is accessed, then power transmission capability is improved, but the inertia support between grids in different regions is blocked and uneven spatial distribution of system inertia is aggravated
Solution Approach 1:
The patent uses spatial mapping of node-level inertia estimates to visualize and analyze the impact of DC transmission lines on inertia distribution. By representing inertia values at their geographic locations and examining spatial patterns, the method reveals how DC lines create boundaries that separate inertia support between regions, providing insights for optimizing DC line placement and operation to maintain adequate inertia support.
Data Source
AI summary
A method and device for estimating spatial distribution of power system inertia based on multi-innovation identification. The method includes: (S1) acquiring time-series data including each node frequency of a power system and a transmission power of a transmission line; decomposing a frequency signal in a series of different spaces to identify a disturbance occurring moment; (S2) analyzing a relationship among node inertia, node frequency and node injection power; constructing an OEMA model to describe an active power-frequency dynamic process of the node after the disturbance occurs; analyzing a coupling relationship between an unknown parameter of the model and the node inertia; (S3) solving the OEMA model based on multi-innovation identification to identity the unknown parameter; and (S4) according to the relationship between a vector of the parameter and the node inertia, calculating each node inertia to estimate the spatial distribution of the power system inertia.