Electrolyser Cell Short-Circuiting for Low-Voltage Ride-Through
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Solution Overview
Problem
Existing electrolysis plants lack the capability to maintain operation during grid faults, particularly voltage dips, leading to potential disconnection and instability in the power grid, which is critical for large-scale integration and decarbonization efforts.
Innovation Solution
An electrolysis plant with a short-circuit arrangement and controllable switches that allow selective short-circuiting of electrolysis cells to adjust voltage demand, maintaining electrolysis current and ensuring continuous operation during grid faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrolysis plant operates with fixed voltage demand during grid faults, then the electrolysis cells may be damaged or disconnected, but the plant cannot maintain continuous operation and contribute to grid stability
Solution Approach 1:
The electrolysis cell array is divided into multiple groups, with controllable switches inserted between groups. This segmentation allows selective short-circuiting of specific cell groups during voltage dips, enabling the plant to maintain operation on remaining cells while contributing to grid stability.
Solution Approach 2:
The controllable switches enable dynamic reconfiguration of the electrolysis cell connections during grid faults. The system can adaptively adjust which cells remain active and which are short-circuited based on real-time grid voltage conditions, transforming a static system into a dynamic fault-tolerant system.
2Reliability
If the electrolysis plant disconnects during voltage dips, then the cells are protected from damage, but the plant cannot provide grid support and may cause instability
Solution Approach 1:
The controllable switches transform the harmful effect of voltage dips into a beneficial grid support mechanism. During voltage dips, the system selectively short-circuits portions of the electrolysis load, preventing complete disconnection while providing reactive power support to stabilize grid voltage, thus converting a potential harm into a stabilizing benefit.
3Productivity
If all electrolysis cells remain active during voltage dips, then continuous production is maintained, but the plant may experience damage or disconnection
Solution Approach 1:
By segmenting the electrolysis cells into multiple groups with controllable switches, the system can maintain production on healthy cell groups while isolating and protecting stressed cells during voltage dips, ensuring both continuous production and cell protection.
Solution Approach 2:
The system dynamically changes the operational parameters of different cell groups by selectively applying short-circuit switches, adjusting which cells receive full voltage and which are partially shorted, thereby optimizing both production continuity and cell protection under varying grid conditions.
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
Enables Fault Ride Through capability, allowing the electrolysis plant to remain connected and operate seamlessly through voltage dips, ensuring stable grid operation and continuous production, reducing system stress and enhancing grid stability.
Implementation Method 1
a rectifier (5), wherein a short circuit arrangement (15) is branching off the DC supply line (13) in parallel to the electrolysis cells (19)
Implementation Method 2
the short-circuit arrangement (15) comprises a plurality of controllable short-circuit switches (17a, 17b, 17c, 17d) that are activatable respectively to short-circuit a selected number of the electrolysis cells (19)
Implementation Method 3
The electrolysis systems use electrical energy to produce hydrogen and oxygen from the water supplied as educt
Data Source
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AI summary
Electrolysis plant and method for operating an electrolysis plant The invention is related to an electrolysis plant (1) comprising an electrolyser (3) with a plurality of electrolysis cells (19) arranged in series connection and a rectifier (5), the rectifier (5) comprising a DC-voltage output (7) that is connected to the electrolyser (3) via a DC supply line (13) and an AC-voltage input (9) that is designed for a connection to a grid (11) and for receiving power from said grid (11) to supply the electrolyser (3) with electrolysis current. A short circuit arrangement (15) is branching off the DC supply line (13) in parallel to the electrolysis cells (19), wherein the short-circuit arrangement (15) comprises a plurality of controllable short-circuit switches (17a, 17b, 17c, 17d) that are activatable respectively to short-circuit a selected number of the electrolysis cells (19) in order to lower the voltage demand while maintaining electrolysis current and keeping the non-short-circuited electrolysis cells (19) in operation. The electrolysis plant 1 is enabled to perform a Low-Voltage-Ride-Through (LVRT) operational mode. The invention is further related to a method for operating an electrolysis plant (1), particularly in a Low-Voltage-Ride-Through (LVRT) operational mode, wherein the electrolysis plant (1) during operation is connected to the grid (11).