Wind Farm Black-Start Using Energy Storage and STATCOM
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Solution Overview
Problem
Wind farms, particularly those with asynchronous generators, are not well-suited for black-start services due to their dependence on external power supplies and inability to maintain synchronicity during grid outages, leading to prolonged restart times and complexities in re-energizing the electrical grid.
Innovation Solution
A method utilizing an energy storage system with an associated converter to disconnect and reconnect wind farms to the grid, allowing simultaneous energization of multiple wind turbine generators in island mode, supported by STATCOMs for voltage stability and reactive power balance, enabling faster and more efficient black-start operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wind turbines with asynchronous generators are used for black-start services, then renewable energy sources can provide black-start capability, but the turbines experience runaway and lose synchronicity when grid connection is lost
Solution Approach 1:
A synchronous condenser is introduced as an intermediary device between the asynchronous generator and the grid. The synchronous condenser maintains synchronicity and provides stable voltage during island mode operation, while the asynchronous generator continues to produce power. This mediator resolves the conflict between using asynchronous generators for black-start and maintaining reliable synchronicity.
Solution Approach 2:
The invention combines asynchronous generators with synchronous condensers in a hybrid configuration. The asynchronous generator provides power generation capability while the synchronous condenser provides grid-forming functionality and synchronicity maintenance. This merging allows wind turbines to provide black-start services without experiencing runaway conditions.
2Reliability
If traditional sequential starting method is used for wind turbines in island mode, then each turbine can be started safely, but the overall start-up time is prolonged
Solution Approach 1:
The synchronous condenser is started and stabilized before the asynchronous generators are connected to the grid. This preliminary action creates a stable voltage source and synchronicity reference that enables multiple asynchronous generators to be started simultaneously or in rapid succession without compromising safety, thereby reducing overall start-up time.
Solution Approach 2:
The starting process is segmented into two independent phases: first starting the synchronous condenser to establish stable voltage and frequency, then separately starting multiple asynchronous generators. This segmentation allows parallel operation of multiple turbines rather than sequential starting, significantly reducing total start-up time while maintaining safety.
3Adaptability or versatility
If wind farms are disconnected from the grid for island mode operation, then black-start services can be provided, but voltage stability and reactive power balance become challenging
Solution Approach 1:
The synchronous condenser provides self-service by generating reactive power locally within the islanded wind farm system. It automatically adjusts its reactive power output to maintain voltage stability and balance reactive power demands of the asynchronous generators and loads, eliminating the need for external grid support during black-start operations.
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 start-up time and complexity of wind farms for black-start services, allowing them to rapidly re-energize the grid and maintain stability during island mode, making it more feasible to use wind farms for black-start services, especially in large and offshore installations.
Implementation Method 1
energizing the AC export cable using said energy storage and the associated converter, energizing at least one part of the wind farm electrical infrastructure via said export cable using said energy storage and the associated converter
Implementation Method 2
providing an energy storage with an associated converter, disconnecting the wind 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
Implementation Method 3
supported by STATCOMs for voltage stability and reactive power balance, enabling faster and more efficient black-start operations
Data Source
AI summary
Methods for black-starting an electrical grid (2) are described herein. For example, a method comprising disconnecting the wind farm (1) from the grid at a first location, said first location being located between the electrical grid (2) and the energy storage (16) with the associated converter (17), energizing the AC export cable (12) using said energy storage (16) and the associated converter (17), energizing at least one part of the wind farm electrical infrastructure via said export cable (12) using said energy storage (16) and the associated converter (17), re-establishing energy supply to said wind farm electrical infrastructure by said wind turbine generators (3, 4), and reconnecting the wind farm (1) to said electrical grid (2) at said first location.