Hierarchical Energy Storage Control for Island Grid Fluctuations

Solution Overview

Problem

Island power grids face challenges in managing new energy generation fluctuations due to the intermittency and randomness of wind and solar power, leading to insufficient active and reactive power compensation, weak voltage support, and significant power abandonment, which affects the safe and stable operation of the grid.

Innovation Solution

A hierarchical control method for an island power grid energy storage system using model predictive control, which implements a rolling dispatch method and constructs an objective function for economic optimization to determine charge and discharge plans for lithium battery and supercapacitor systems, effectively responding to both short-term and long-term dispatch instructions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If existing energy storage control strategy is used to smooth short-term random fluctuation, then power quality at new energy access point is improved, but long-term output variation of new energy is not addressed, resulting in significant wind and solar abandonment

Engineering Contradiction:

Improvepower qualityVSAvoidnew energy consumption capacity

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The control strategy is segmented into two distinct layers: intraday control layer that handles short-term fluctuation smoothing, and real-time control layer that addresses long-term output variation. This segmentation allows each layer to focus on specific time scales and objectives, preventing the trade-off between power quality and new energy consumption capacity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a temporal dimension by implementing hierarchical control across different time scales (intraday vs. real-time). This dimensional approach allows the system to simultaneously optimize for both short-term power quality and long-term new energy consumption, resolving the contradiction by operating in multiple time dimensions rather than a single time scale.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of energy

If energy storage system responds to grid-wide economic dispatch instructions, then economic operation of island power grid is improved, but new energy generation fluctuation is not effectively suppressed

Engineering Contradiction:

Improveeconomic operationVSAvoidpower generation stability

Core Design Contradiction:

Loss of energyVSStability of the object's composition

Solution Approach 1:

The control strategy is segmented into two distinct layers: intraday control layer that handles short-term fluctuation smoothing, and real-time control layer that addresses long-term output variation. This segmentation allows each layer to focus on specific time scales and objectives, preventing the trade-off between power quality and new energy consumption capacity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The intraday control layer acts as an intermediary between the real-time control layer and the new energy power generation system. It receives long-term output variation instructions and translates them into actionable control signals for the real-time layer, enabling coordinated optimization of both economic operation and power generation stability across different time scales.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If energy storage system suppresses new energy fluctuation, then safe and stable operation of island power grid is improved, but new energy consumption capacity is not sufficiently enhanced

Engineering Contradiction:

Improvegrid operation stabilityVSAvoidnew energy consumption capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The control strategy is segmented into two distinct layers: intraday control layer that handles short-term fluctuation smoothing, and real-time control layer that addresses long-term output variation. This segmentation allows each layer to focus on specific time scales and objectives, preventing the trade-off between power quality and new energy consumption capacity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The hierarchical control strategy ensures continuous useful action by maintaining coordinated operation across both intraday and real-time layers. The intraday layer continuously optimizes for new energy consumption while the real-time layer continuously suppresses fluctuations, creating an uninterrupted dual-function control system that simultaneously achieves both reliability improvement and consumption capacity enhancement.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS11831165B2Hierarchical control method for island power grid energy storage system for increasing new energy generation fluctuation

Publication Date: 2023.11.28 STATE GRID ZHEJIANG ELECTRIC POWER COMPANY TAIZHOU POWER SUPPLY

AI summary

A hierarchical control method for an island power grid energy storage system for increasing new energy generation fluctuation is disclosed. The method includes implementing a rolling dispatch method based on an idea of model predictive control; comprehensively considering a response capability of the energy storage system to grid-wide economic dispatch instructions and life loss of energy storage lithium batteries, and constructing an objective function of an intraday control model of the energy storage system with economic optimization; and constructing, on a basis of satisfying the objective function of the intraday control model, a real-time control model of the energy storage system and solving the model, and determining charge and discharge plans of a lithium battery energy storage system and a supercapacitor energy storage system.