Reactive Power Configuration for Offshore Wind Grid Voltage Stability
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Solution Overview
Problem
Existing power grid systems face challenges in ensuring stable voltage and economical reactive power configuration when integrating large-scale offshore wind power, particularly in onshore grids, due to insufficient consideration of static and dynamic reactive power support in various scenarios.
Innovation Solution
A method and terminal for configuring reactive power capacity in power grids with large-scale offshore wind power connections, involving static voltage stability index calculation, N-2 fault analysis, and multi-type reactive power optimization to identify weak points and optimize reactive power compensation devices for both normal and fault conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If offshore wind power is connected on a large scale and at multiple points to the onshore power grid, then the proportion of renewable energy increases, but voltage stability deteriorates due to increased load on transmission lines
Solution Approach 1:
The patent performs preliminary identification of weak nodes in voltage stability before actual faults occur. By calculating static voltage stability indices and performing N-2 fault analysis in advance, the system pre-determines which nodes require reactive power compensation, enabling proactive rather than reactive voltage stability management
Solution Approach 2:
The patent introduces reactive power compensation devices as intermediary elements between the offshore wind power connection points and the onshore power grid. These devices act as mediators to regulate voltage and provide reactive power support, decoupling the direct impact of large-scale wind power connections from grid voltage stability
2Reliability
If reactive power compensation devices are configured to ensure voltage stability, then voltage regulation performance improves, but system cost increases
Solution Approach 1:
The patent applies reactive power compensation selectively at locally identified weak nodes rather than uniformly across the entire grid. By using static voltage stability indices and dynamic voltage drop area indices to identify specific weak nodes, the system configures compensation devices only where necessary, optimizing the balance between voltage regulation performance and system cost
Solution Approach 2:
The patent considers both normal operation and severe fault conditions (N-2 faults) when configuring reactive power compensation. By designing the system to handle extreme scenarios, the solution ensures adequate voltage support under all conditions while avoiding over-compensation in normal operation through the optimization model
3Reliability
If comprehensive fault analysis and optimization modeling are performed, then voltage stability under severe faults improves, but computational complexity and analysis time increase
Solution Approach 1:
The patent segments the complex voltage stability assessment into distinct components: static voltage stability index calculation for normal operation, and dynamic voltage drop area index calculation for fault conditions. This segmentation allows each aspect to be analyzed separately using appropriate methods, reducing overall computational complexity while maintaining comprehensive coverage
Data Source
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AI summary
Provided are a method and a terminal for configuring reactive power capacity of a power grid to which offshore wind power is connected on a large scale. Static voltage stability indices of substations in a regional power grid to which the offshore wind power is connected on the large scale and at multiple points and relative dynamic voltage drop area indices for an N-2 fault are calculated. Thus, weak nodes in voltage stability are located, thereby implementing a prediction of a risk to the voltage stability of the regional power grid. These nodes are used as candidate reactive power compensation configuration nodes. An objective function is established as the minimum total cost of reactive power compensation devices at the candidate reactive power compensation configuration nodes. A multi-type reactive power optimization configuration model including static voltage stability constraints, voltage stability constraints in a faulty state, and other constraints is solved. Thus, a configured static reactive power compensation meets a voltage regulation demand during normal operation of the power grid, and a configured dynamic reactive power compensation meets a demand for reactive power support in the event of a severe fault in an important transmission channel. In addition, the total cost of a reactive power compensation configuration is minimized so that a stable voltage and an economical reactive power configuration of a system with a high proportion of offshore wind power are ensured.