Wind Turbine Pitch System Hydraulic Fluid Testing

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Solution Overview

Problem

Hydraulic accumulators in wind turbine pitch systems have a shorter service life due to high strain, requiring frequent checks that necessitate stopping the turbine, leading to decreased production and increased risk of component failure.

Innovation Solution

A hydraulic pitch system with a testing unit that measures the properties of the hydraulic fluid in real-time, allowing for non-invasive testing of accumulators without stopping the turbine, using a system accumulator to replace the manifold accumulator during testing, and a control system to monitor and manage the results.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If accumulators are checked frequently to ensure reliability, then the reliability of the pitch system is improved, but the productivity of the wind turbine decreases due to frequent stops

Engineering Contradiction:
Improvereliability of pitch systemVSAvoidproduction of wind turbine
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The testing unit performs preliminary testing of the accumulator by measuring pressure drop and fluid properties before failures occur. This allows early detection of degradation trends, enabling planned maintenance during scheduled downtime rather than forced stops for inspection, thus maintaining productivity while ensuring reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual inspection methods with an automated testing unit that electronically measures pressure drop, fluid temperature, and other properties. This substitution eliminates the need for physical disassembly and manual checking, allowing continuous monitoring without stopping the turbine, thereby resolving the contradiction between reliability monitoring and productivity.

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

2Measurement precision

If accumulators are inspected by disconnecting and visual examination, then the measurement precision of accumulator state is improved, but the time required for inspection increases

Engineering Contradiction:
Improvedetection accuracy of accumulator stateVSAvoidinspection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The accumulator system performs self-diagnosis through the integrated testing unit that continuously monitors its own state by measuring pressure drop across itself and analyzing fluid properties. This self-service capability provides precise measurement of accumulator health without requiring external inspection or disconnection, eliminating time loss while maintaining high measurement precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The testing unit acts as an intermediary between the accumulator and the control system, indirectly measuring accumulator state through fluid property analysis and pressure drop measurement. This intermediary approach provides accurate detection of accumulator degradation without direct physical intervention or disconnection, resolving the time versus precision contradiction.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If manual inspection of accumulators is performed, then the device complexity is reduced, but the ease of operation decreases due to required entry into nacelle or hub

Engineering Contradiction:
Improvesimplicity of pitch systemVSAvoidease of accumulator testing
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The accumulator system with integrated testing unit performs self-monitoring and self-diagnosis, automatically measuring its own state and reporting to the control system. This eliminates the need for operators to manually enter the nacelle or hub for inspection, greatly improving ease of operation while maintaining simple device architecture through automated rather than manual processes.

Inventive Principle:
Principle #25Self-service

4Reliability

If frequent maintenance stops are scheduled, then the reliability of the system is improved, but the productivity and energy production decrease

Engineering Contradiction:
Improvesystem reliabilityVSAvoidwind energy production
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The testing unit performs preliminary assessments of accumulator health by measuring pressure drop and fluid properties, identifying degradation trends before failures occur. This enables condition-based maintenance scheduling during planned downtime rather than reactive maintenance requiring unplanned stops, improving reliability while minimizing impact on energy production.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system receives continuous feedback from the testing unit about accumulator state and fluid properties, enabling real-time monitoring and predictive maintenance planning. This feedback loop allows optimization of maintenance scheduling to balance reliability requirements with productivity goals, avoiding unnecessary stops while ensuring timely intervention before failures.

Inventive Principle:
Principle #23Feedback

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 solution extends the service life of hydraulic accumulators, reduces turbine downtime, and minimizes the risk of component failure by enabling continuous operation during maintenance and early detection of defects, thus improving overall wind energy production.

Implementation Method 1

The flow constriction means causes the pressure drop to occur slowly enough to make it easier to detect a failure in the accumulator.

Methodology Applied
Scientific EffectPressure drop: Pressure Drop

Implementation Method 2

a hydraulic cylinder for adjusting a pitch angle of the blade

Methodology Applied
Scientific EffectHydraulic force: Hydraulic Press

Implementation Method 3

an accumulator having gas on one side and usually oil on the other side to absorb pulsations

Methodology Applied
Scientific EffectGas compression: Compression

Data Source

PatentEP2402596B1Wind turbine blade pitch system
Publication Date: 2017.12.20 VESTAS WIND SYSTEMS AS
  • EP2402596B1 patent drawingFigure 1
  • EP2402596B1 patent drawingFigure 2
  • EP2402596B1 patent drawingFigure 3

AI summary

The present invention relates to a pitch system for pitching a blade of a wind turbine by means of a hydraulic fluid, comprising a manifold which comprises a hydraulic cylinder for adjusting a pitch angle of the blade and an accumulator hydraulically connected to the cylinder, the hydraulic fluid having at least one measurable property, wherein the system further comprises a testing unit adapted to measure at least one property of the hydraulic fluid in fluid communication with the accumulator. Furthermore, the invention relates to a method for measuring the property of the hydraulic fluid.