Power Line Stability Evaluation for Sub-Synchronous Oscillation Prevention

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Solution Overview

Problem

Existing power line management systems fail to prevent sub-synchronous oscillations (SSO) by adjusting operation settings proactively, leading to potential equipment damage and instability.

Innovation Solution

A power line management system that evaluates stability by comparing PES power usage rates with a stability index, using a processor to calculate stability scores and control PES power generation to prevent oscillations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If operation settings of RES are changed after oscillation is detected to suppress the oscillation, then the oscillation can be reduced, but equipment damage may have already occurred and response time is delayed

Engineering Contradiction:
Improvepower line stabilityVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary stability evaluation by calculating stability indices and monitoring operational parameters before oscillations occur. The stability evaluation unit continuously assesses the power line state using pre-established stability criteria, enabling proactive adjustment of RES operation settings to prevent oscillation onset rather than reacting after detection

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback monitoring of power line stability through the stability evaluation unit, which compares real-time operational data against stability indices. This feedback mechanism enables dynamic adjustment of RES operation to maintain stability, with the evaluation results directly informing control decisions to prevent oscillation development

Inventive Principle:
Principle #23Feedback

2Reliability

If stability evaluation is performed continuously to prevent oscillation, then oscillation can be suppressed, but system complexity and computational load increase

Engineering Contradiction:
Improvepower line stabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stability evaluation system is segmented into distinct functional modules: stability index calculation unit, stability evaluation unit, and separate monitoring components. Each module performs a specific function (calculating indices, evaluating stability, monitoring parameters), which simplifies the overall system architecture and enables independent optimization of each component while maintaining comprehensive stability assessment

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system utilizes parameter-based stability indices that can be calculated from standard operational measurements. By transforming complex stability assessment into computations based on measurable parameters (power, voltage, frequency), the system achieves continuous evaluation without requiring complex additional sensing or measurement infrastructure

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4683152A1Power line management system and power line management method
Publication Date: 2026.01.21 HITACHI LTD
  • EP4683152A1 patent drawingFigure 1
  • EP4683152A1 patent drawingFigure 2
  • EP4683152A1 patent drawingFigure 3

AI summary

In view of instability of a power line due to expansion of introduction of RES, in order to evaluate stability of the power line and suppress occurrence of an oscillation such as an SSO, a power line management system includes: a storage unit which stores power load prediction information indicating prediction of a power load in the power line and power generation prediction information indicating prediction of power generated by a power plant in the power line; an index calculation unit which calculates stability index information indicating a stability index for evaluating stability of the power line on the basis of the power load prediction information and the power generation prediction information; a power information acquisition unit which acquires power load information indicating an actual power load in the power line and power generation information indicating power actually generated by a power plant in the power line from the power line via the communication network; and a stability evaluation unit which calculates a stability score related to the power line on the basis of the power load information and the power generation information, and generates a stability evaluation result indicating the stability of the power line on the basis of the stability score and the stability index information.