Oscillation Analysis Apparatus for Grid Subsystem Contribution
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Solution Overview
Problem
Current methods are inadequate for determining the contribution of grid subsystems to oscillations in angle within an electrical grid, making it difficult to identify and address negative contributors to grid stability.
Innovation Solution
A method that determines the contribution of grid subsystems to oscillations in angle by analyzing the phase relationship between measurable properties such as frequency and angle, allowing for the identification of positive, negative, or neutral contributions, even in partially observed systems, using phase shifts and phasor measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase relationship analysis is used to determine subsystem contributions to oscillation, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses phase relationship as an intermediary parameter to indirectly determine subsystem contributions to oscillation. Instead of directly measuring contribution, the system measures phase angles of oscillation signals from different subsystems and uses the phase difference to calculate contribution. This intermediary approach enables precise measurement without requiring complex direct contribution measurement devices.
Solution Approach 2:
The patent replaces complex mechanical or direct measurement systems with signal processing and phase analysis methods. By substituting direct contribution measurement with phase relationship analysis of electrical signals, the system achieves high precision while reducing physical device complexity. The phase angle measurements and trigonometric calculations provide a mathematical substitute for direct physical measurement of subsystem contributions.
2Reliability
If comprehensive grid monitoring is implemented to identify all oscillation contributors, then reliability is improved, but loss of information increases due to measurement losses
Solution Approach 1:
The patent implements feedback through the phase relationship analysis mechanism. By continuously monitoring phase angles and their relationships, the system provides feedback about subsystem contributions to oscillation. This feedback loop enables the system to maintain reliable identification of oscillation sources even when individual measurements are lost, as the phase relationship information is continuously updated and can be reconstructed from available data.
Solution Approach 2:
The patent changes the measurement parameter from direct contribution measurement to phase angle measurement. This parameter transformation makes the system more resilient to measurement losses because phase angles can be derived from standard voltage and frequency measurements that are already available in grid monitoring systems. The phase parameter is more robust to data loss and can be reconstructed more easily than direct contribution measurements.
3Productivity
If detailed phase analysis is performed to identify negative contributors, then productivity is improved in terms of identifying actionable targets, but difficulty of detecting and measuring increases
Solution Approach 1:
The patent makes the phase analysis system universal by using standard grid measurement quantities (voltage, frequency, angle) that are already measured by existing PMU (Phasor Measurement Unit) infrastructure. The same measurement system serves multiple functions: monitoring grid state, detecting oscillations, and identifying contribution sources. This multi-functionality reduces the difficulty of measurement while maintaining high identification efficiency.
Solution Approach 2:
The patent uses copies of standard measurement signals (voltage and frequency phasors) to derive phase relationship information. Instead of requiring specialized sensors or direct measurements of subsystem contributions, the system uses copies of already-available measurement data. This copying approach simplifies detection and measurement while enabling detailed phase analysis for identifying negative contributors to oscillation.
Data Source
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AI summary
The present invention relates to apparatus (10) for determining a contribution of at least one grid subsystem of plural grid subsystems to oscillation in angle or grid oscillation in an electrical grid (12). The apparatus (10) is configured to receive a first quantity which corresponds to oscillation in angle at a first grid subsystem (14). The apparatus (10) is also configured to receive a second quantity which corresponds to oscillation in angle at a second grid subsystem (16). The apparatus (10) comprises a processor (32) which is operative to determine a contribution of at least one of the first and second grid subsystems to oscillation in angle or grid oscillation with the contribution being determined in dependence on a phase relationship between the first and second quantities.