Wind Turbine Generator Damage-Based Load Control
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Solution Overview
Problem
Conventional wind turbine generators face challenges in adapting their operation to their useful life, as existing fatigue life evaluation methods do not effectively consider the operational mode changes needed to extend the design life beyond the original intended years, leading to potential premature failure due to unmanaged cumulative damage.
Innovation Solution
A method for controlling wind turbine generators by calculating cumulative damage degrees and comparing them with threshold values to determine operation modes, shifting to low-load modes when damage thresholds are exceeded, and adjusting pitch angles and rotation speeds to reduce stress on critical components, thereby extending the service life and preventing unexpected failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wind turbine generator operates in normal operation mode continuously, then productivity is improved, but the cumulative damage degree increases leading to reduced reliability
Solution Approach 1:
The operation mode is dynamically adjusted based on real-time cumulative damage degree calculations. The control unit transitions between normal operation mode and low-load operation mode according to the calculated damage levels, making the system adaptable rather than static. This resolves the contradiction by allowing full productivity when damage is low while protecting reliability when damage accumulates.
Solution Approach 2:
The patent changes operational parameters (pitch angle, rotation speed) based on the cumulative damage degree. When damage thresholds are exceeded, the system modifies these parameters to reduce load on specific components, effectively using parameter adjustment to balance productivity and reliability throughout the component's lifecycle.
2Reliability
If the pitch angle is adjusted to feather side to reduce load, then reliability is improved by suppressing cumulative damage, but productivity decreases due to reduced wind energy capture
Solution Approach 1:
The patent applies partial action by adjusting the pitch angle only to the extent necessary to suppress cumulative damage, not necessarily to the maximum feather position. The control unit calculates the minimal required adjustment based on damage thresholds, allowing the turbine to maintain higher productivity while still achieving reliability protection when needed.
Solution Approach 2:
The operation mode switching occurs periodically based on accumulated damage thresholds rather than continuously. The system alternates between normal and low-load modes, allowing full productivity during low-damage periods while providing reliability protection when damage accumulates, creating a rhythmic pattern of operation.
3Reliability
If the rotation speed is limited to extend service life, then reliability is improved, but productivity is reduced due to lower power output
Solution Approach 1:
The rotation speed limit is dynamically set based on the cumulative damage degree of the drive train components. Rather than applying a fixed speed restriction, the system adjusts the speed threshold according to real-time damage calculations, allowing higher speeds when damage is low and imposing limits only when necessary to protect component life.
Solution Approach 2:
The control unit calculates and monitors cumulative damage in advance before critical failure occurs. By detecting damage accumulation trends early, the system can proactively adjust rotation speeds to prevent excessive damage, rather than waiting for actual component degradation to manifest.
Data Source
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AI summary
A method of controlling a wind turbine 1 includes: accumulating a cumulative damage degree Du of each evaluation point of the wind turbine in a unit period over an entire evaluation period, to calculate a total cumulative damage degree Dt of the entire evaluation period at each evaluation point; comparing the Dt at each of the evaluation points with a first threshold value (P*Q) and comparing an increase rate dDt/dt of Dt at each evaluation point with a second threshold value to evaluate fatigue of a part to which each evaluation point belongs; and determining an operation mode based on an evaluation result into a normal operation mode or a low-load operation mode in which an output is suppressed compared with the normal operation mode. This may be utilized to prolong the useful life of wind turbine 1 to produce more power during the life of the wind turbine 1.