Booster Transformer Soft-Closing for Offshore Wind Park Grid Connection

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Solution Overview

Problem

Offshore wind parks face challenges in meeting onshore electricity grid requirements due to voltage and current transients during switching-in, and existing solutions like Static VAR devices are vulnerable and costly, especially for offshore use, while also needing to comply with environmental regulations.

Innovation Solution

A booster transformer with an intermediate circuit operating at medium-voltage and an energy dissipating element switchable between operational and non-operational conditions is used to dampen current and voltage transients, allowing for a soft-closing scheme that reduces transient effects and extends the life of insulation systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a booster transformer with an energy dissipating element is used to dampen voltage and current transients during switching-in, then the quality of electrical connection is improved and the lifespan of insulation systems is extended, but the device complexity increases due to the additional intermediate circuit and switchable energy dissipating element

Engineering Contradiction:
Improvequality of electrical connectionVSAvoidstructure of booster transformer
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

An intermediate circuit is introduced between the primary and secondary windings of the booster transformer. This intermediate circuit contains a switchable energy dissipating element (resistor) that acts as a mediator to dampen voltage and current transients during switching-in operations, thereby improving connection quality while managing the added complexity through a structured intermediate layer

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The energy dissipating element in the intermediate circuit is made switchable between operational and non-operational conditions. This dynamic configuration allows the system to adapt its damping characteristics based on operational requirements, enabling transient suppression during switching-in while maintaining normal operation with reduced losses

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If Static VAR devices based on power electronics are installed to meet plant capability curves, then the reactive power control capability is improved, but the reliability decreases due to vulnerability of power electronics especially for off-shore use

Engineering Contradiction:
Improvereactive power control capabilityVSAvoidrobustness of power electronic devices
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention replaces vulnerable power electronic Static VAR devices with a transformer-based solution using electromagnetic principles. The booster transformer with its intermediate circuit and energy dissipating element provides reactive power control capability through electromagnetic induction and resistive damping, eliminating the reliability issues associated with offshore power electronics while maintaining adaptability through switchable configurations

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The solution effectively eliminates or reduces voltage and current transients, limiting electrodynamic and thermal stresses, thereby increasing the lifespan of electrical system components and ensuring compliance with environmental regulations.

Implementation Method 1

an energy dissipating element switchable between an operational and non-operational condition

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

booster transformer for coupling an AC-connection of an off-shore wind-park to an on-shore electricity grid

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2396866B1Ac-connection of an off-shore wind-park to an on-shore electricity grid and booster transformer for providing such an ac-connection
Publication Date: 2013.04.03 VISERGE
  • EP2396866B1 patent drawingFigure 1
  • EP2396866B1 patent drawingFigure 2
  • EP2396866B1 patent drawingFigure 3

AI summary

The present invention relates to a method for switching-in an electricity grid of an off-shore wind park to an on-shore electricity grid, to a booster transformer modified for switching-in an electricity grid of an off-shore wind park to an on-shore electricity grid and to an AC- connection for operating an electricity grid of an off-shore wind-park switched-in to an onshore electricity grid.