Wind Power Plant Grid Voltage Regulation During Fault Recovery
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Solution Overview
Problem
Wind power plants connected to weak grids face challenges in maintaining grid stability during fault events due to high impedance and voltage fluctuations, which can lead to tripping and re-triggering issues due to excessive reactive current support.
Innovation Solution
A method for controlling wind power plants that includes detecting grid voltage deviations, transitioning through fault ride-through and recovery states, and using wind turbine power controllers to generate reactive currents based on voltage differences to regulate grid voltage back to a predetermined reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wind power plant provides predetermined reactive current injection during voltage dip to support grid voltage recovery, then grid voltage support is improved, but the wind turbine generator may trip due to exceeding high voltage limit in weak grid
Solution Approach 1:
The patent implements dynamic adjustment of reactive current injection based on real-time grid voltage measurements. The control system continuously monitors grid voltage and adapts the reactive current magnitude accordingly, transitioning from static predetermined injection curves to dynamic control that responds to actual grid conditions, thereby preventing voltage limit exceedance while maintaining support effectiveness
Solution Approach 2:
The patent employs feedback control by measuring actual grid voltage and using this information to adjust reactive current injection in real-time. The control system compares measured voltage against reference values and modifies the reactive current output to maintain voltage within acceptable limits, creating a closed-loop control system that prevents tripping while providing continuous support
2Adaptability or versatility
If the wind power plant operates in weak grid with high impedance, then grid connection is established, but voltage fluctuations exceed continuous operating voltage requirements
Solution Approach 1:
The patent changes operational parameters dynamically by adjusting reactive power output based on detected voltage deviations. When voltage fluctuations exceed continuous operating limits, the system modifies its power output characteristics to compensate for weak grid conditions, enabling stable operation despite high impedance and voltage variability inherent in weak grid environments
3Speed
If additional reactive current support is provided during voltage dip recovery in weak grid, then grid voltage recovery is accelerated, but wind turbine generator trips due to exceeding voltage limits
Solution Approach 1:
The patent applies dynamic control during voltage recovery by continuously adjusting reactive current injection levels based on real-time voltage measurements. Rather than applying fixed additional support, the system modulates the reactive current magnitude to accelerate recovery while preventing voltage from exceeding generator limits, achieving both fast recovery and continuous operation
Solution Approach 2:
The patent uses feedback control during voltage recovery by monitoring grid voltage continuously and adjusting reactive current injection accordingly. The control system detects when voltage approaches critical levels and reduces reactive current to prevent tripping, while maintaining sufficient support to accelerate recovery, creating a self-regulating mechanism that balances speed and reliability
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
Enables wind power plants to continue supporting the grid during faults and recover voltage stability without tripping, adhering to grid code requirements without additional hardware, and allowing for efficient reactive power support in weak grid environments.
Implementation Method 1
Wind energy can be captured by a wind turbine generator, which is a rotating machine that converts the kinetic energy of the wind into mechanical energy, and the mechanical energy subsequently into electrical power
Implementation Method 2
the wind turbine generator or a wind power plant is expected to similarly provide a reactive current support in assistance to grid voltage recovery
Data Source
Figure 1
Figure 2
Figure 3~3A
AI summary
A method for controlling a wind power plant, the wind power plant including a plant controller for controlling a plurality of wind turbine generators. The method for controlling a wind power plant allows the wind power plant to continue operating through a grid fault in a weak grid environment. In the method, a fault recovery process is carried out with a wind turbine power controller during a wind turbine fault recovery state to determine a grid voltage (VWTG), compare the grid voltage to a predetermined reference voltage (Vref) to obtain a difference value, and determine a current reference (QrefVC) based on the difference value for generating a reactive current (Idref) for regulating the grid voltage to the predetermined reference grid voltage. A corresponding wind power plant is further provided.