Renewable Energy Reactive Power Control via Dynamic Capability Adjustment

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Solution Overview

Problem

Renewable energy systems, such as wind farms, face challenges in determining actual reactive power limits under various system conditions, leading to inefficiencies in meeting reactive power demands without requiring costly on-load tap changing transformers.

Innovation Solution

A system and method that adjusts reactive power limits based on actual reactive power capability by aggregating feedback signals from individual power generation units, using a farm-level control system with inner loop voltage regulators and outer loop reactive power/power factor regulators to distribute and clamp reactive power commands, allowing for dynamic adjustment of reactive power limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If on-load tap changing transformers are installed at each power generation unit, then reactive power capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvereactive power capabilityVSAvoidtransformer complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the reactive power compensation function from individual transformer-based solutions and implements it through a centralized control system that aggregates reactive power capabilities across multiple generation units. The farm-level controller calculates and distributes reactive power commands without requiring complex transformers at each unit.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The control system enables power generation units to serve multiple functions: they can operate in power generation mode under normal conditions and switch to reactive power compensation mode when voltage deviations occur, eliminating the need for dedicated transformer equipment at each unit.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If reactive power capability is provided by adjusting active power production, then device complexity is reduced, but productivity decreases

Engineering Contradiction:
Improvetransformer requirementVSAvoidactive power production
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The system dynamically adjusts the balance between active and reactive power production based on real-time voltage conditions. The farm-level controller continuously monitors voltage deviations and temporarily reduces active power production only when and where needed to provide reactive power support, minimizing impact on overall productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements partial reduction of active power production rather than complete shutdown. The control system calculates the minimum necessary active power reduction to achieve the required reactive power output, maintaining productivity while meeting reactive power demands during voltage events.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If rated reactive power limits are used for individual power generation units, then ease of operation is improved, but measurement precision of actual reactive power capability deteriorates

Engineering Contradiction:
Improvereactive power limit settingVSAvoidactual reactive power limit
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the farm-level controller receives actual voltage and power data from individual generation units, compares it against the power factor requirement, and adjusts reactive power commands accordingly. This closed-loop control continuously refines the actual reactive power capability assessment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary calculations of reactive power requirements based on predicted voltage deviations and power factor targets before actual voltage events occur. The farm-level controller pre-positiones reactive power reserves to ensure rapid response while maintaining operational simplicity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3059830B1Reactive power compensation based on reactive power capability of a renewable energy system
Publication Date: 2019.10.23 GENERAL ELECTRIC CO
  • EP3059830B1 patent drawingFigure 1
  • EP3059830B1 patent drawingFigure 2
  • EP3059830B1 patent drawingFigure 3

AI summary

Systems and methods 600 for controlling a renewable energy system 200 based on actual reactive power capability of the renewable energy system are provided. The reactive power output of the renewable energy system 200 can be controlled based at least in part on an initial reactive power limit. The initial reactive power limit can be determined based on rated reactive power for the power generation units 202 in the renewable energy system 200. When a difference between a reactive power demand and the actual reactive power production of the renewable energy system fall outside a threshold, the initial reactive power limit can be adjusted to a corrected reactive power limit that is closer to the actual reactive power capability of the renewable energy system.