Wind Turbine Drive Train Lubrication for Off-Grid Idling

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Solution Overview

Problem

Wind turbines in remote locations face challenges in maintaining adequate lubrication of drive train components, especially during idling or when disconnected from the grid, as existing systems either provide excessive lubrication leading to friction losses or lack sufficient lubrication when auxiliary power is unavailable.

Innovation Solution

A dual-reservoir lubrication system that uses gravity to supply lubrication liquid to drive train components, with separate reservoirs for different components and valves that adjust based on grid connection status, ensuring continuous lubrication without active pumping, and incorporating heat exchangers for temperature control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high amount of lubrication liquid is used in the drive train, then reliable lubrication is ensured during off-grid operation, but friction losses increase and performance decreases

Engineering Contradiction:
Improvelubrication reliabilityVSAvoidfriction losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The lubrication system is divided into separate reservoirs for different drive train components. The first reservoir supplies lubrication liquid to the main shaft and generator, while the second reservoir supplies to the gearbox. This segmentation allows optimized lubrication for each component without requiring excessive lubrication liquid throughout the entire system, thereby reducing friction losses while maintaining reliable lubrication where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts lubrication supply based on grid connection status. During grid-connected operation, the pump supplies lubrication liquid on demand. During off-grid operation, the system automatically creates oil sumps in the reservoirs to ensure continuous lubrication without external power. This dynamic adaptation ensures reliable lubrication during critical off-grid periods without maintaining high lubrication levels during normal operation, minimizing friction losses.

Inventive Principle:
Principle #15Dynamics

2Reliability

If lubrication liquid is actively pumped to all components, then adequate lubrication is provided during grid-connected operation, but the system becomes dependent on auxiliary power availability

Engineering Contradiction:
Improvelubrication supplyVSAvoidgrid independence
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary action by creating oil sumps in the reservoirs before off-grid operation begins. The reservoirs are designed to automatically accumulate lubrication liquid and maintain adequate levels for the duration of expected off-grid periods. This preliminary preparation ensures continuous lubrication supply during grid disconnection without requiring active pumping, thereby providing grid independence while maintaining reliable lubrication.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The lubrication system serves itself during off-grid operation through passive mechanisms. The reservoirs automatically maintain lubrication liquid levels and supply components without external power assistance. The system design allows gravity and pressure differential to drive lubrication delivery during off-grid periods, eliminating dependence on auxiliary power while ensuring adequate lubrication supply.

Inventive Principle:
Principle #25Self-service

3Reliability

If separate reservoirs are used for different drive train components, then lubrication is optimized for each component, but device complexity increases

Engineering Contradiction:
Improvecomponent-specific lubricationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The reservoirs serve multiple functions: they store lubrication liquid, create oil sumps during off-grid operation, and supply lubrication to specific components. The first reservoir serves the main shaft and generator, while the second reservoir serves the gearbox. This multi-functionality allows the system to provide component-specific lubrication optimization without proportionally increasing complexity, as the same structural elements perform multiple lubrication-related tasks.

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

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

Ensures reliable lubrication of wind turbine drive trains during both grid-connected and off-grid operations, minimizing friction losses and maintaining performance by optimizing lubrication liquid distribution and temperature management.

Implementation Method 1

The oil drains primarily by gravity from the first reservoir and/or the second reservoir to the respective component of the drive train

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

The lubrication system can further comprise a heat exchanger for tempering, more particular for cooling, the lubrication liquid

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

The main shaft can comprise heaters for heating lubrication liquid in at least one oil chamber in the main shaft

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3571403B1Lubrication system for a drive train of a wind turbine, wind turbine and method of lubricating
Publication Date: 2023.03.29 SIEMENS GAMESA RENEWABLE ENERGY DEUT GMBH
  • EP3571403B1 patent drawingFigure 1
  • EP3571403B1 patent drawingFigure 2
  • EP3571403B1 patent drawingFigure 3

AI summary

A lubrication system for a drive train of a wind turbine comprises a main oil tank (201) containing a lubrication liquid, in particular oil, for lubricating the drive train when the wind turbine has connection to a grid and a main reservoir (204) which is separate from the main oil tank (201) and contains lubrication liquid for the drive train when the wind turbine (10) has no connection to the grid. The main reservoir (204) comprises a first reservoir (214) containing a first amount of lubrication liquid for at least a first component of the drive train and a second reservoir (224) containing a second amount of lubrication liquid for at least a second component of the drive train. The first component is different from the second component. The lubrication system is configured to supply the oil from the main reservoir (204) to the drive train when the wind turbine has no grid connection for creating an oil sump in at least the second component of the drive train (100). Furthermore, a wind turbine comprising such a drive train and a method of lubricating a drive train of a wind turbine are suggested.