Power Network Impedance Analysis for IBR Instability Root Cause Detection

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Solution Overview

Problem

The increasing penetration of inverter-based resources (IBRs) in power grids leads to reliability challenges such as unexpected tripping, control interactions, declining system inertia, and instability, necessitating improved methods for predicting and identifying the root causes of power network instabilities.

Innovation Solution

An impedance-based technique is employed to analyze power networks, combining network and IBR impedance matrices to generate a characteristic matrix, determine eigenvalues, and use sensitivity matrices to identify peaks that indicate the root cause of instability, allowing for precise detection of unstable regions and their causes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If inverter-based resources penetration level is increased, then renewable energy integration is improved, but power system reliability deteriorates

Engineering Contradiction:

Improverenewable energy integrationVSAvoidpower system reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent performs preliminary stability analysis by calculating the characteristic impedance matrix and its eigenvalues before actual instability occurs. The sensitivity matrices are pre-computed to identify potential root causes of instability, allowing preventive actions to be taken before reliability deteriorates during high IBR penetration periods

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism by continuously monitoring system impedance characteristics and comparing them against stability criteria. When eigenvalues indicate potential instability, the system provides feedback to operators about the root causes (specific buses or IBRs), enabling real-time corrective actions to maintain reliability despite high IBR penetration

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If inverter-based resources penetration level is increased, then renewable energy integration is improved, but system inertia and frequency stability deteriorate

Engineering Contradiction:

Improverenewable energy integrationVSAvoidfrequency stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent replaces traditional mechanical inertia-based stability assessment with an impedance-based electrical analysis. Instead of relying on physical rotor inertia from synchronous generators, the system uses electrical impedance matrices and eigenvalue analysis to assess frequency stability, providing a complementary approach that works effectively with inverter-based resources

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If inverter-based resources penetration level is increased, then renewable energy integration is improved, but grid strength and voltage stability deteriorate

Engineering Contradiction:

Improverenewable energy integrationVSAvoidvoltage stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent creates a universal stability assessment framework that simultaneously evaluates multiple aspects of power system stability (frequency, voltage, and overall grid strength) using a single impedance-based approach. The characteristic impedance matrix and its eigenvalues provide multi-functional insights into different stability dimensions, allowing comprehensive assessment without requiring separate analysis methods for each stability type

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Device complexity

If traditional stability analysis methods are used, then computational complexity is reduced, but detection precision of instability root causes deteriorates

Engineering Contradiction:

Improvecomputational complexityVSAvoidinstability root cause detection precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the power system into discrete buses and IBRs, representing each component's impedance characteristics as separate matrix elements. This segmentation allows the complex stability analysis to be broken down into manageable calculations of individual impedance matrices, their products, and resulting eigenvalues, making the sophisticated analysis computationally tractable while maintaining high precision in root cause identification

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20260072070A1Enhanced detection of instability regions in power systems with inverter-based resources

Publication Date: 2026.03.12 GE INFRASTRUCTURE TECH LLC

AI summary

Methods, systems, and devices for detecting instabilities and their root causes in power networks may include identifying a network impedance matrix of a power network; determining impedance matrices for inverter-based resources (IBRs) of the power network; generating, by the at least one processor, a characteristic impedance matrix based on a product of the network impedance matrix and an IBR impedance matrix of the impedance matrices; determining a first sensitivity matrix of an nth eigenvalue of the characteristic impedance matrix on the network impedance matrix; determining a second sensitivity matrix of the nth eigenvalue of the characteristic impedance matrix on the IBR impedance matrix; identifying a first peak of the first sensitivity matrix and a second peak of the second sensitivity matrix; and determining, based on the first peak and the second peak, that at least one bus of the power network is a root cause of an instability.