Wind Power Plant Weak Grid Control via Active Power Reference Adjustment
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Solution Overview
Problem
Wind power plants connected to weak grids face challenges such as voltage instability, reactive power losses, and unstable operation due to high grid impedance, leading to issues during both steady-state and transient conditions, including voltage fluctuations and unwanted trips.
Innovation Solution
A method for operating a wind power plant that includes a power plant controller capable of determining a weak grid criterion, switching to a weak grid mode by reducing active power references when grid voltage deviates, and maintaining reduced power output until the grid recovers, thereby stabilizing the grid and preventing retriggering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wind power plant operates at full active power in weak grid, then productivity is maximized, but voltage stability deteriorates and causes unwanted trips
Solution Approach 1:
The control system dynamically adjusts the active power reference based on real-time grid voltage conditions. When voltage deviation is detected, the active power reference is reduced; when voltage recovers, the reference is increased back to original levels. This dynamic adjustment resolves the contradiction by making power generation adaptive to grid stability requirements.
Solution Approach 2:
The system implements feedback control by continuously monitoring grid voltage and using this information to adjust the active power reference. The feedback loop detects voltage deviations and triggers appropriate power reduction, preventing unwanted trips while maintaining productivity as much as possible under stable grid conditions.
2Reliability
If wind power plant provides reactive power compensation, then voltage stability is improved, but device complexity increases due to extra compensation equipment
Solution Approach 1:
The existing power plant controller is made multi-functional by enabling it to perform both active power control and reactive power compensation tasks. Instead of adding separate dedicated compensation equipment, the controller is configured to provide dynamic reactive power support as part of its weak grid mode functionality, thereby improving voltage stability without increasing device complexity.
Solution Approach 2:
The wind power plant uses its own control system to provide the necessary reactive power compensation rather than relying on external dedicated compensation equipment. The controller automatically adjusts reactive power output based on grid voltage conditions, making the system self-sufficient in maintaining voltage stability.
Data Source
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AI summary
In various embodiments of the present disclosure, there is provided a method of operating a wind power plant in a weak grid environment in order to achieve desired system stability criteria and to support an electrical grid during small disturbances or faults, the wind power plant being coupled to an electrical grid, and including a power plant controller for controlling a plurality of wind turbine generators of the wind power plant, the method including: determining whether the electrical grid fulfils a weak grid criterion; setting the power plant controller to operate in a weak grid mode when the weak grid criterion is fulfilled, the weak grid mode including: reducing and providing an active power reference according to which the plurality of wind turbine generators are controlled, when a grid voltage deviates beyond a threshold voltage from a normal or recommended operating voltage range during steady state operation of a wind power plant; and generating a reduced amount of active power with each of the plurality of wind turbine generators based on the provided active power reference& controlling the active power ramp rates, when the electrical grid recovers from the voltage deviation or a fault. A corresponding wind power plant is further provided. The coordinated operation of the plant level control and WTG level control plays an important role.