Linear Load Shedding for Power Grid Frequency Stabilization

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Solution Overview

Problem

Existing electrical network stabilization methods through load shedding often result in abrupt power variations, leading to instabilities due to non-linear power shedding dynamics, which can cause frequency deviations and require costly additional power generation.

Innovation Solution

A method and system that periodically measure instantaneous shedding power at consumer sites, calculate estimated shedding power, and set threshold frequencies for each site to ensure a substantially linear variation of shedding power with frequency, allowing for progressive load disconnection when network frequency drops below predetermined thresholds, thereby stabilizing the network with minimal jerks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If load shedding is performed abruptly at sub-network level to reduce power consumption quickly, then the response speed to frequency drop is improved, but the network stability deteriorates due to jerky power variations

Engineering Contradiction:
Improveresponse speedVSAvoidnetwork stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent segments the load shedding process into multiple progressive steps across different frequency thresholds. Instead of a single abrupt disconnection, loads are shed progressively as frequency drops through predefined thresholds (e.g., 49.5 Hz, 49.0 Hz, 48.5 Hz), transforming one jerky action into multiple controlled steps that maintain stability while responding quickly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic threshold frequencies for different sites rather than uniform static thresholds. Each site receives customized threshold frequencies based on its characteristics, allowing the system to adapt the load shedding response dynamically to specific conditions while maintaining overall network stability through coordinated progressive action.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If uniform load shedding thresholds are applied across all sites, then the device complexity is reduced, but the manufacturing precision of power variation linearity deteriorates

Engineering Contradiction:
Improvecontrol system complexityVSAvoidpower variation linearity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by assigning different threshold frequencies to different sites based on their specific characteristics and power consumption profiles. Each site receives customized thresholds tailored to its local conditions, ensuring that the aggregate power variation across all sites follows a substantially linear relationship with frequency while maintaining relatively simple control logic at each individual site.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3084910B1Method to stabilize a power grid using load shedding
Publication Date: 2018.05.09 INSTITUT NAT POLYTECHN DE GRENOBLE
  • EP3084910B1 patent drawingFigure 1
  • EP3084910B1 patent drawingFigure 2
  • EP3084910B1 patent drawingFigure 3

AI summary

The invention relates to a method of stabilization between a high frequency and a low frequency, of an electrical network supplying several sub-networks (22), each sub-network comprising a sub-network manager (24) and supplying N consumer sites (28), each site, j, comprising sheddable loads (34), the method comprising for each sub-network the following steps: ensuring a communication between each site and the sub-network manager thereof; periodically measuring the value of the sheddable power consumed at each site; deducing for each site an estimated sheddable power; and dispatching to each site j (28) a threshold frequency, such that sheddable loads (34) of this site are unplugged when the frequency of the network drops below the threshold frequency, in which the sub-network manager (24) calculates the threshold frequencies in such a way that the variation of the sheddable powers as a function of frequency is substantially linear.