Renewable Power Plant Frequency Response Using Storage Reserve Control

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Solution Overview

Problem

Existing renewable energy power plants struggle to provide a fast frequency response to frequency deviations in power networks, which can destabilize the grid and violate grid codes, necessitating a quicker correction of frequency deviations.

Innovation Solution

A control strategy for renewable energy power plants that utilizes an energy storage system and renewable energy generators to rapidly increase active power output during frequency deviations, followed by a staged approach to conserve energy reserves and maximize generator contributions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the energy storage system continuously supplies active power to satisfy the active power request, then the frequency deviation is corrected, but the energy storage is depleted quickly and cannot sustain long-term frequency support

Engineering Contradiction:

Improvefrequency support capabilityVSAvoidenergy storage duration

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The control method dynamically adjusts the active power setpoint for the energy storage system based on real-time frequency measurements and generator output. The energy storage system transitions from continuous high-power discharge to a more sustainable operation mode, adjusting its power contribution according to the evolving frequency condition and generator response, thereby extending its operational duration while maintaining frequency support capability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The method utilizes the active power reserve already available in the renewable energy generators at the time of frequency deviation. By immediately dispatching this pre-existing generator reserve to counteract the frequency drop, the system reduces the initial burden on the energy storage system, allowing it to conserve energy while still meeting the active power request through coordinated generator-stORAGE operation.

Inventive Principle:

Principle #10Preliminary action

2Speed

If the renewable energy generators increase active power output rapidly, then the frequency response is faster, but the generators may exceed their operational limits or lose stability

Engineering Contradiction:

Improvefrequency response timeVSAvoidgenerator operational stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The energy storage system acts as an intermediary between the frequency deviation event and the renewable energy generators. It provides immediate high-speed power response to address the frequency drop, while simultaneously modulating the power demand placed on the generators. This intermediary role allows the system to achieve fast frequency response without forcing generators to operate beyond their stable operational limits.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The control method dispatches only the necessary portion of active power from the energy storage system and generators to meet the active power request, rather than maximizing output from both sources simultaneously. By calculating the precise power shortage and allocating it optimally between storage and generators, the system achieves adequate frequency response while maintaining generator operational stability and conserving energy storage.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If the system prioritizes fast frequency response, then grid stability is improved, but energy storage is depleted quickly reducing future response capability

Engineering Contradiction:

Improvegrid stabilityVSAvoidenergy storage depletion

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The control method continuously monitors frequency deviations, generator active power output, and energy storage state of charge. Based on this feedback, it dynamically adjusts the active power setpoint for the energy storage system and the dispatch instructions for generators. This closed-loop feedback control ensures fast frequency response when needed while preventing excessive energy storage depletion, as the system adapts its power allocation strategy based on real-time system conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes operational parameters dynamically - specifically, the active power setpoint for the energy storage system is adjusted as a function of frequency deviation magnitude, generator response, and remaining energy storage. This parameter adaptation allows the system to provide aggressive frequency support when the grid needs it most while transitioning to more conservative operation as energy storage depletes or when generators can meet the demand independently.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12407167B2Renewable energy power plant fast frequency response

Publication Date: 2025.09.02 VESTAS WIND SYSTEMS AS

AI summary

Aspects of the present invention relate to a method of controlling a renewable energy power plant connected to a power network. The renewable energy power plant comprises one or more renewable energy generators having an active power reserve for supplying additional active power to the power network and an energy storage system having an active power store. In response to detecting a frequency event on the power network a power sequence is implemented to manage the additional active power contributions from the energy storage system and the one or more renewable energy generators to satisfy the active power request.