Wind Turbine Voltage Control via Reactive Current Droop
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Solution Overview
Problem
Conventional wind farm control architectures face limitations in voltage regulation due to steady-state operation variations caused by small deviations in grid loading, leading to inefficiencies and loss of voltage regulation, especially when local control is based on constant power factor or voltage, and farm-level control is inactive.
Innovation Solution
A method involving a wind turbine generator control system that receives a voltage command signal from a higher-level controller, generating a reactive current command, and adjusting it based on local reactive power droop characteristics and real power offset values to regulate reactive power, ensuring faster voltage stabilization and balanced reactive power output across turbines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If local control with constant power factor or voltage is used, then each wind turbine generator can operate independently, but voltage flicker is aggravated and voltage regulation is lost when farm-level control is inactive
Solution Approach 1:
The control system is segmented into two independent but coordinated controllers: a farm-level controller that provides centralized voltage regulation, and local turbine controllers that provide autonomous reactive power compensation. Each controller operates independently but contributes to overall voltage stability, allowing the system to maintain reliability even when one level is inactive.
Solution Approach 2:
The local controller continuously monitors terminal voltage and reactive power output, using this feedback to dynamically adjust reactive current injection. This closed-loop control enables the local controller to compensate for voltage deviations caused by wind gusts and grid disturbances, maintaining voltage regulation without requiring constant farm-level control intervention.
2Reliability
If constant voltage control is applied on each generator, then voltage is maintained at setpoint, but steady-state operation varies significantly with small grid loading deviations causing loss of voltage regulation
Solution Approach 1:
The control system transitions from static constant voltage control to dynamic reactive power compensation. The local controller continuously adapts reactive current injection based on real-time terminal voltage measurements and reactive power calculations, enabling the system to respond dynamically to grid loading variations while maintaining voltage stability.
Solution Approach 2:
The controller dynamically changes the reactive current reference based on terminal voltage deviations and reactive power requirements. By adjusting the reactive current parameter in response to grid conditions, the system maintains adaptability to loading variations while preserving voltage maintenance capability.
3Reliability
If farm-level voltage control is implemented, then overall voltage stability is improved, but fast communication and aggressive action from farm-level to local level are required
Solution Approach 1:
Each wind turbine generator is equipped with an autonomous local controller that independently performs reactive power compensation based on local voltage measurements. This self-service capability eliminates the need for complex real-time communication between farm-level and local controllers, reducing system complexity while maintaining voltage stability through distributed intelligence.
4Reliability
If reactive current is increased to maintain voltage during steady-state variations, then voltage regulation is preserved, but overall efficiency of the wind turbine generator decreases
Solution Approach 1:
The controller continuously monitors terminal voltage and reactive power output, providing continuous reactive power compensation only when needed to maintain voltage within acceptable limits. This continuous but conditional operation ensures voltage regulation is preserved while avoiding unnecessary reactive current injection that would reduce generation efficiency.
Data Source
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AI summary
A system 100 and associated method for reactive power generation for a wind turbine generator 110 includes receiving a higher-than-generator level voltage command signal 155. A reactive current is determined for the wind turbine generator 110 in response to the voltage command signal 155 and is transmitted to a controller 150 of the wind turbine generator 110 for generating a real and reactive power based on the reactive current command 280. A trim value may be generated and applied to the voltage command signal 155.