HVDC Offshore Wind Overload Reduction Circuit

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Solution Overview

Problem

Offshore wind energy systems face challenges in timely regulation to prevent overload due to actuator device inertia, leading to potential damage from power overshoots during strong winds and gusts, necessitating a solution to maintain maximum power output while ensuring safety and reducing the risk of component failure.

Innovation Solution

Incorporating an overload detection device and an overload reduction circuit that reduces current at the high-voltage direct current transmission station when an overload is detected, allowing for prompt dissipation of excess power without across-the-board throttling of wind turbines, utilizing switchable loads, chopper circuits, or voltage booster circuits for rapid regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If blade pitch actuators are used to regulate rotor speed, then wind turbine speed can be controlled, but the actuator inertia prevents timely control response to avoid overload

Engineering Contradiction:
Improveoverload protectionVSAvoidcontrol response time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The control device activates the overload reduction circuit in advance when an overload situation is detected, before the mechanical actuators can respond. This preliminary electrical action reduces the current received at the HVDC transmission station immediately, bypassing the slow mechanical blade pitch adjustment and preventing overload damage to components.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If wind turbines are throttled across the board to prevent overload, then component damage is avoided, but maximum power output cannot be achieved

Engineering Contradiction:
Improvecomponent safetyVSAvoidpower output
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

Instead of uniformly throttling all wind turbines, the invention applies overload reduction locally and selectively. The control device activates the overload reduction circuit only for specific turbines experiencing overload conditions, allowing other turbines to continue operating at maximum power output. This localized approach maintains system reliability while maximizing overall productivity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The overload reduction circuit provides partial action by reducing current only to the extent necessary to prevent overload, rather than completely shutting down turbines. The control device modulates the current reduction to maintain safety margins while preserving as much power output as possible, avoiding excessive throttling.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If maximum current is transmitted to maximize energy yield, then electricity generation is optimized, but component overload and damage risk increases

Engineering Contradiction:
Improveenergy yieldVSAvoidoverload damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control device continuously monitors current levels and activates the overload reduction circuit when overload conditions are detected. This feedback mechanism dynamically adjusts the current transmission to maintain optimal energy yield while preventing component damage, creating a self-regulating system that responds to real-time operating conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static current transmission to dynamic current control. The overload reduction circuit enables the system to adapt current levels in real-time based on operating conditions, allowing maximum current transmission during normal operation for optimized energy yield, while automatically reducing current when overload risk is detected to prevent component damage.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2759699B1Method of operating an offshore windpark with a high voltage direct current transfer station.
Publication Date: 2019.07.17 INNOGY SE
  • EP2759699B1 patent drawingFigure 1
  • EP2759699B1 patent drawingFigure 2
  • EP2759699B1 patent drawingFigure 3~4

AI summary

The system has several high voltage direct current transmission stations (6) which are electrically connected to wind turbines (4). An overload detection unit (20) is provided for detecting an overload of the wind energy system. A control device (22) drives an overload reduction circuit (24) which is provided for the detection of the overload, such that overload reduction circuit is triggered, and received power of high voltage direct current transmission station is reduced.