Power Grid Event Screening Using DC-AC Flow Margining

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Solution Overview

Problem

Current power system stabilization systems face challenges in reducing computational resources while maintaining accuracy, especially in large-scale systems, as existing methods either simplify models too much or are inadequate for analyzing overloads or voltage stability.

Innovation Solution

A power system stabilization system that includes a power system computation unit for performing simple and event computations, and a margin setting unit to calculate a screening margin, allowing for reduced computational resources while maintaining accuracy by using DC and AC power flow computations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If full AC power flow computation is performed for all event cases, then computation accuracy is maintained, but computational resources and time increase significantly

Engineering Contradiction:
Improvecomputation accuracyVSAvoidcomputational efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The computation process is segmented into two stages: first, a simplified DC power flow computation is performed for all event cases to quickly identify potentially problematic scenarios; second, full AC power flow computation is performed only for the screened event cases that require detailed analysis. This segmentation reduces the number of computationally intensive AC simulations while maintaining accuracy for critical cases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of performing full AC power flow computation for all event cases (excessive action), the method applies partial action by conducting detailed AC analysis only for a subset of event cases that are identified as potentially problematic through the initial DC computation screening. This reduces overall computational resources while maintaining necessary accuracy.

Inventive Principle:
Principle #16Partial or excessive action

2Productivity

If simplified DC power flow computation is used for all event cases, then computational resources are reduced, but computation accuracy deteriorates

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidcomputation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The computation process is segmented into two stages: first, a simplified DC power flow computation is performed for all event cases to quickly identify potentially problematic scenarios; second, full AC power flow computation is performed only for the screened event cases that require detailed analysis. This segmentation reduces the number of computationally intensive AC simulations while maintaining accuracy for critical cases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The DC power flow computation acts as an intermediary screening mechanism between the event cases and the detailed AC power flow analysis. It filters out event cases that do not require detailed analysis, allowing the system to maintain high computational efficiency while ensuring accuracy for cases that truly need it.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If model simplification is applied to reduce computational scale, then computational resources are suppressed, but the ability to evaluate local overload conditions deteriorates

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidoverload evaluation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The computation process is segmented into two stages: first, a simplified DC power flow computation is performed for all event cases to quickly identify potentially problematic scenarios; second, full AC power flow computation is performed only for the screened event cases that require detailed analysis. This segmentation reduces the number of computationally intensive AC simulations while maintaining accuracy for critical cases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method applies different computation qualities to different event cases: simplified DC computation is applied to the majority of cases where high accuracy is not critical, while full AC computation is applied locally to specific event cases that are identified as potentially problematic. This ensures high accuracy is maintained where needed while reducing overall computational burden.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4404408A1Power system stabilization system and power system stabilization method
Publication Date: 2024.07.24 HITACHI LTD
  • EP4404408A1 patent drawingFigure 1
  • EP4404408A1 patent drawingFigure 2
  • EP4404408A1 patent drawingFigure 3

AI summary

Provided is a power system stabilization system (1) capable of suppressing computation resources while maintaining computation accuracy for evaluating a state of a power system. A power system stabilization system (1) includes a power system computation unit (2) that receives a power system state, a power system model, and an event case as inputs and executes at least one of simple event computation and event computation, and a margin setting unit (3) that receives a margin setting parameter as an input and calculates a screening margin from a result of the simple event computation and a result of the event computation for an event case targeted by the power system computation unit (2). By the margin setting unit (3) calculating the screening margin from the results of both the simple event computation and the event computation, a possibility of erroneous screening can be curbed to maintain the computation accuracy, a system state of an evaluation target can be reduced according to power flow computation, and computation resources can be suppressed.