Electrolyzer Grid Disconnection for Wind Plant Overvoltage Protection
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Solution Overview
Problem
Renewable power plants with electrolyzers are vulnerable to high voltages, which can damage the electrolyzers, and existing systems lack effective protection mechanisms, especially when the power plant trips at the point of common coupling, leading to islanding conditions and potential high voltage increases.
Innovation Solution
Implement a method for renewable power plants that includes low voltage detection at wind turbines and electrolyzers, with converters to inject AC power into the grid, and controlled disconnection of electrolyzers from the internal grid to prevent high voltage damage, using proximity-based voltage detection and timed disconnection for additional protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power plant trips at the point of common coupling causing islanding conditions, then the wind turbines may inject reactive power to support the grid, but this causes rapid voltage increase that can damage the electrolyzer system
Solution Approach 1:
The electrolyzer system detects low voltage conditions and preemptively disconnects from the internal grid before the wind turbines can inject reactive power that would cause harmful voltage increases. This preliminary protective action prevents the harmful effect from occurring in the first place.
Solution Approach 2:
A detection and control system acts as an intermediary between the wind turbines and the electrolyzer system. It monitors voltage conditions and controls the circuit breaker to disconnect the electrolyzer when necessary, mediating between the grid support function and the protection of the electrolyzer from voltage damage.
2Power
If the electrolyzer system remains connected to the internal grid during low voltage conditions, then it can potentially support the grid, but it risks damage from subsequent high voltage increases
Solution Approach 1:
The system preemptively disconnects the electrolyzer from the internal grid when low voltage is detected, preventing subsequent high voltage damage before it can occur. This prioritizes equipment protection over grid support contribution.
Solution Approach 2:
The electrolyzer system performs preliminary voltage detection and disconnection actions before the harmful high voltage condition develops. This preliminary protective action ensures the electrolyzer is isolated before damage can occur.
3Reliability
If the electrolyzer system disconnects immediately upon detecting low voltage, then it is protected from high voltage damage, but it cannot contribute to grid support during actual low voltage ride through events
Solution Approach 1:
The control system continuously monitors voltage conditions and uses feedback to determine whether to disconnect or remain connected. By detecting whether the low voltage is actual (grid-wide) or apparent (islanding condition), the system makes intelligent decisions about when to disconnect for protection and when to remain connected for grid support.
Solution Approach 2:
The system dynamically adjusts its connection state based on real-time voltage conditions. Rather than a fixed disconnection policy, the electrolyzer can switch between connected and disconnected states depending on whether the situation requires protection or grid support, making the protection strategy adaptive to actual conditions.
4Speed
If the electrolyzer system uses the wind turbine's low voltage detection, then it can respond quickly to islanding conditions, but it may disconnect during actual low voltage events when grid support is needed
Solution Approach 1:
The electrolyzer control system uses feedback from voltage detection to distinguish between actual low voltage events and apparent low voltage caused by islanding. This feedback mechanism prevents false disconnections during genuine grid events while still providing rapid protection during islanding conditions.
Solution Approach 2:
The system performs preliminary detection of the cause of low voltage before taking disconnection action. By detecting whether the low voltage is real or apparent in advance, the system avoids premature or false disconnections that would occur with immediate response to any low voltage condition.
Data Source
AI summary
The invention relates to a method for operating a renewable power plant (100) comprising at least one wind turbine (101) and an electrolyzer system (110), the renewable power plant is connectable with a grid (190) via a circuit breaker (123) located at a point of common coupling (PCC), wherein the renewable power plant comprises an internal grid (191) connecting the at least one wind turbine and the electrolyzer system with the point of common coupling, wherein the method comprises detecting a low voltage at any of the at least one wind turbine, and electrically disconnecting the electrolyzer system from the internal grid in response to detecting the low voltage.