Double-Fed Wind Farm Stability Control for Sub-Synchronous Oscillation
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Solution Overview
Problem
Existing technologies fail to address the sub-synchronous oscillation stability issues in grid-connected wind farms, particularly focusing on the interaction between wind farm units, which affects the stability and security of the power grid.
Innovation Solution
A stability control method and system for double-fed wind farms that adjusts operation state parameters based on energy coefficients, including inter-machine induction and circulation coefficients, to improve damping and stability by considering the energy flow and interaction characteristics between units and the grid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unit operation parameters are adjusted to improve sub-synchronous oscillation damping, then unit stability is improved, but system complexity increases
Solution Approach 1:
The patent changes operational parameters (rotor voltage, rotor current, transmission line parameters) based on calculated energy coefficients. By dynamically adjusting these parameters according to the energy transfer characteristics, the system improves sub-synchronous oscillation damping without requiring complex control structures.
Solution Approach 2:
The system calculates energy coefficients based on actual unit operation states and automatically determines the necessary parameter adjustments. This self-service approach eliminates the need for external complex control systems, as the units self-regulate based on their energy interaction characteristics.
2Reliability
If inter-machine energy interaction is controlled, then sub-synchronous oscillation stability is improved, but measurement and detection difficulty increases
Solution Approach 1:
The patent replaces direct physical measurement of energy interactions with calculations based on readily available electrical parameters (voltages, currents, frequencies). By using mathematical models to compute energy coefficients from standard electrical measurements, the system avoids the need for complex energy flow sensors or measurement devices.
Data Source
AI summary
The application relates to a stability-control method and system for grid-connected system of double-fed wind farm, which belongs to the technical field of wind power generation system. The method comprises: collecting operation state parameters of each unit in the system; according to the operation state parameters of each unit, determining a mutual voltage between the units, an interlocking phase angle between the units, and a sub-synchronous current of each unit; according to the mutual voltage between the units, the interlocking phase angle between the units and the sub-synchronous current component of each unit, determining an energy coefficient of each unit, and then obtaining a total energy coefficient; according to the total energy coefficient, regulating the operation state parameters of each unit.