Wind Farm Black Start with Export Cable Energization
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Solution Overview
Problem
Existing methods for black-starting an electrical grid using wind farms are slow and complex, as they rely on sequential startup of wind turbines and lack system inertia, making it difficult to rapidly reconnect the grid after a blackout.
Innovation Solution
A method involving an offshore wind farm connected to onshore energy storage with a converter and a synchronous condenser, allowing for simultaneous energization of multiple wind turbines and providing high momentary power demands during grid reconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wind turbines are started sequentially using traditional black-start methods, then the system can be restarted, but the black-start time becomes excessively long
Solution Approach 1:
The patent applies preliminary action by pre-charging the DC link capacitor in the converter before the grid blackout occurs. This stored energy in the capacitor is then used to immediately restart the wind turbine without needing sequential startup procedures, enabling parallel black-start capability across multiple turbines and dramatically reducing the overall black-start time.
2Adaptability or versatility
If asynchronous generators are used in wind turbines, then they can generate power, but they lose synchronicity and experience runaway when grid connection is lost
Solution Approach 1:
The patent uses the DC link capacitor as an intermediary energy storage element that decouples the asynchronous generator from the grid connection requirement. The capacitor maintains the DC voltage and allows the generator to operate independently during islanded mode, preventing runaway while maintaining generation capability. This intermediary enables the asynchronous generator to function reliably without direct grid synchronization.
3Duration of action of moving object
If double-fed asynchronous generators are used, then they can ride-through short grid losses, but they experience runaway after 0.1 to 3 seconds and require cumbersome restart procedures
Solution Approach 1:
The patent employs the DC link capacitor as a short-term energy buffer that provides immediate power during the critical restart transition. This disposable-like energy storage element bridges the gap between grid loss and generator restart, allowing the system to tolerate grid interruptions indefinitely without experiencing runaway, and enables simple restart procedures by maintaining DC voltage throughout the transition.
4Productivity
If permanent magnet generator wind turbines with AC/DC and DC/AC conversion are used, then they can generate power, but they need external power to energize the converters before production
Solution Approach 1:
The patent implements self-service by using the wind turbine's own generator to charge the DC link capacitor during the startup process. The generator produces power that directly energizes the DC/AC converter without requiring external grid power, enabling the system to be self-sufficient during black-start operations and eliminating the need for external energization sources.
5Productivity
If photovoltaic plants with DC/AC converters are used, then they can generate power, but they need external power from the grid to power up the converters
Solution Approach 1:
The patent applies preliminary action by pre-charging the DC link capacitor in photovoltaic systems before grid loss occurs. This stored energy enables the DC/AC converter to start up autonomously without external grid power, granting photovoltaic plants black-start capability and making them adaptable to grid failure scenarios where they can immediately resume power generation.
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
This approach significantly reduces the time required for black-starting a wind farm and stabilizing the grid, enabling faster reconnection and support for the electrical grid during re-energization.
Implementation Method 1
providing an energy storage with an associated converter
Implementation Method 2
providing a synchronous condenser, energizing said synchronous condenser
Data Source
AI summary
Described are systems and methods for black-starting an electrical grid, comprising disconnecting an energy farm from the grid at a first location, said first location being located between the electrical grid and the energy storage with the associated converter, providing a synchronous condenser, energizing the AC export cable using said energy storage and the associated converter, energizing at least one part of the energy farm electrical infrastructure via said AC export cable using said energy storage and the associated converter, re-establishing energy supply to said energy farm electrical infrastructure by said electric generators, energizing said synchronous condenser, and reconnecting the energy farm to said electrical grid at said first location.