Wind Turbine Active Power Reference Control After Frequency Events
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Solution Overview
Problem
Conventional wind turbine generators experience delays in ramping back to normal active power levels after frequency deviations due to mismatches between set points and output limits, leading to inefficiencies and potential penalties from transmission system operators.
Innovation Solution
Implementing a method and system that ensures active power references are set equal to or within the relevant limits during and immediately after frequency events, using adaptive limiters or ramp rate initialization to match set points with output limits, thereby eliminating delays in ramping back to baseline levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active power references are determined based on predefined curves during frequency events, then frequency support is provided, but wind-up occurs causing delays in ramping back to normal levels
Solution Approach 1:
The system continuously monitors the relationship between active power references and output limits, and dynamically adjusts the references based on feedback from the frequency event status and limit comparisons. This feedback mechanism prevents wind-up by ensuring references remain within achievable limits throughout the frequency event and recovery period.
Solution Approach 2:
The control system transitions from static predefined curves to dynamic reference determination that adapts in real-time based on frequency conditions and power limits. During frequency events, references are dynamically adjusted to match actual output capabilities, and during recovery, ramp rates are dynamically controlled to optimize the return to normal operation without causing wind-up delays.
2Reliability
If active power output levels are increased during under-frequency events, then network support is provided, but actual power output is limited by available wind causing mismatch between controller commands and turbine output
Solution Approach 1:
The system changes the parameter of active power references from fixed predefined values to dynamically adjusted values that account for actual power limits. By comparing determined power values against upper and lower limits and adjusting references accordingly, the system ensures commands match physical capabilities, eliminating the mismatch between controller intentions and turbine actual output.
Solution Approach 2:
The control system introduces an intermediary comparison and adjustment mechanism between the frequency-based power determination and the turbine's actual power output. This intermediary layer checks determined power values against available limits and modifies references to ensure they are achievable, preventing wind-up and ensuring smooth transition between frequency support mode and normal operation.
3Power
If active power references are set outside limits during frequency events, then maximum frequency support is provided, but wind-up occurs delaying return to baseline power levels
Solution Approach 1:
The system takes preliminary action by proactively limiting active power references to achievable values during frequency events, rather than allowing them to exceed limits and then correcting later. By pre-adjusting references to match actual output capabilities and maintaining this alignment throughout the event, the system prevents wind-up from occurring in the first place, enabling immediate power restoration when frequency returns to normal.
Solution Approach 2:
The control system maintains continuous alignment between active power references and actual output capabilities throughout the entire frequency event and recovery period. By continuously monitoring limits and adjusting references to remain within achievable ranges, the system ensures uninterrupted useful action - providing maximum frequency support when needed while maintaining the capability for immediate power restoration without wind-up delays.
Data Source
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AI summary
Aspects of the present invention relate to methods (200, 300) for controlling active power output of a wind turbine generator (14) in response to a frequency event on a power network (16) to which the wind turbine generator (14) is connected, wherein the active power output of the wind turbine generator (14) is limited to be below an upper active power limit and/or above a lower active power limit. The methods (200, 300) comprise determining and dispatching active power references to a controller (15) of the wind turbine generator (14) for controlling the wind turbine generator (14). The methods operate to ensure that the value of the active power reference immediately after the frequency event is within the allowable active power range, thereby avoiding any mismatch between the reference and the output that may cause a delay in returning to normal operation.