Reactive Power Allocation in Wind Plant Internal Grid

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Solution Overview

Problem

Wind turbines in power plants face instability issues that can lead to damage due to fluctuations in internal grid voltage, requiring effective management of reactive power to maintain desired voltage levels.

Innovation Solution

A method involving a power plant controller that detects voltage changes in the internal grid, calculates the necessary reactive power, and allocates its generation between High Voltage Direct Current (HVDC) converters and wind turbine converters based on their capabilities, using signals from a grid monitor to ensure stable voltage levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reactive power is generated to maintain voltage stability in the internal grid, then voltage stability is improved, but the complexity of power management increases

Engineering Contradiction:
Improvevoltage stabilityVSAvoidpower management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention divides the wind power plant into multiple independent control zones (individual wind turbines and the central HVDC converter), allowing distributed reactive power management. Each wind turbine converter and the HVDC converter can independently generate or consume reactive power based on local voltage conditions, reducing the complexity of centralized control while maintaining overall voltage stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention implements dynamic reactive power allocation where the capability of each converter (wind turbine converters and HVDC converter) is continuously assessed and adjusted based on real-time operating conditions. The controller dynamically determines how much reactive power each converter should provide to maintain voltage stability, adapting to changing grid conditions and converter capabilities rather than using fixed allocation schemes.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple converters are used to generate reactive power, then voltage maintenance capability is improved, but the coordination complexity increases

Engineering Contradiction:
Improvevoltage maintenance capabilityVSAvoidconverter coordination complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention employs a feedback mechanism where the controller continuously monitors the internal grid voltage and the capability status of each converter. Based on this feedback, the controller dynamically adjusts the reactive power output of individual wind turbine converters and the HVDC converter to maintain voltage within desired limits. This closed-loop control simplifies coordination by using real-time status information to make automated allocation decisions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Each converter (wind turbine converters and HVDC converter) is equipped with the capability to autonomously assess its own reactive power generation capacity and contribute to voltage maintenance according to its current operating state. The controllers at each converter can independently determine their reactive power contribution based on local measurements and pre-defined capability curves, reducing the need for complex centralized coordination while ensuring collective voltage stability.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively maintains desired voltage levels in the internal grid, preventing damage to wind turbine components and ensuring compliance with grid requirements by dynamically managing reactive power generation.

Implementation Method 1

calculating an amount of reactive power that should be generated to maintain the voltage of the internal grid at a desired voltage

Methodology Applied
Scientific EffectReactive power generation: Electromagnetic Induction

Data Source

PatentEP2659564B1Reactive power management for wind power plant internal grid
Publication Date: 2019.07.24 VESTAS WIND SYSTEMS AS
  • EP2659564B1 patent drawingFigure 1
  • EP2659564B1 patent drawingFigure 2
  • EP2659564B1 patent drawingFigure 3

AI summary

A wind power plant comprising a plurality of wind turbine converters coupled to a High Voltage Direct Current (HVDC) converter via an internal grid and a power plant controller. The power plant controller is configured to monitor a voltage of the internal grid, and allocate responsibility for generating reactive power to the HVDC converter and the wind turbine converters to maintain thevoltage of the internal grid at a desiredvoltage.