Hydroelectric Unit Grid Coupling With Shared Variable Frequency Drive
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Solution Overview
Problem
Existing methods for coupling a hydroelectric power plant with multiple units to a grid are slow and require costly variable frequency drives, lacking a solution for starting multiple generators efficiently without additional investments.
Innovation Solution
A method that successively connects generators of multiple hydroelectric units to a common variable frequency drive and then to the grid, stabilizing each unit's speed before disconnecting from the drive, allowing for faster grid coupling without additional investments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a variable frequency drive is used to start a hydroelectric turbine, then the starting process can be controlled, but the cost increases significantly
Solution Approach 1:
The patent merges the starting control function into the existing grid connection process by sequentially connecting generators to the grid. The first generator provides voltage support that enables the second generator to start and connect without requiring a separate variable frequency drive system, thus eliminating the costly VFD while maintaining controlled starting capability.
Solution Approach 2:
The first hydroelectric generator serves the dual purpose of both power generation and voltage support for starting the second generator. The system uses its own operational generator to provide the necessary electrical conditions for starting another generator, eliminating the need for external starting equipment like variable frequency drives.
2Productivity
If traditional starting methods are used for multiple hydroelectric units, then each unit requires independent control equipment, but the time response to provide power to the grid is slow
Solution Approach 1:
The first generator is started and connected to the grid in advance, establishing the necessary voltage and frequency conditions before the second generator is started. This preliminary action creates the electrical environment needed for rapid sequential connection of additional generators, enabling fast response to grid demands without requiring complex independent control equipment for each unit.
Solution Approach 2:
The grid connection system serves multiple functions: it provides power reception, voltage stabilization, and starting support for multiple generators simultaneously. By using the grid and the first generator as a universal starting support system, the patent eliminates the need for separate control equipment for each generator while achieving rapid sequential connection.
3Device complexity
If hydroelectric units are connected to the grid sequentially, then equipment costs are reduced, but the overall time to provide full power capacity is extended
Solution Approach 1:
The patent maintains continuous useful action by having the first generator remain connected and operational while providing voltage support for starting the second generator. Instead of completing one connection fully before starting the next, the system maintains overlapping operations where the first generator continuously supports the grid and enables simultaneous or rapid sequential connection of additional generators, thus reducing total time without requiring additional equipment.
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
Reduces the time response to provide power to the grid by stabilizing and connecting multiple hydroelectric units efficiently, achieving faster power injection without the need for costly variable frequency drives.
Implementation Method 1
connecting the generator of the first hydroelectric unit to the variable frequency drive and stabilizing the speed of the first hydroelectric unit
Implementation Method 2
a first control loop to control the opening of the guide vanes; a second control loop, to control the variable frequency drive
Data Source
AI summary
The invention concerns a method for coupling a hydroelectric power plant in a turbine mode to a grid, in order to generate power for a grid, said hydroelectric power plant comprising at least a first hydroelectric unit (10) and a second hydroelectric unit (100), each provided with a runner (6) mechanically coupled to a shaft line (8) and to a generator, a distributor (4) comprising guide vanes to control a flow of water to said runner, said hydroelectric power plant further comprising a variable frequency drive (20), the method comprising:a) starting the rotation of at least said first hydroelectric unit (10) and said second hydroelectric unit (100);b) connecting the variable frequency drive (20) to the generator of the first hydroelectric unit (10) and to the grid and stabilizing the speed of the first hydroelectric unitc) connecting the first hydroelectric unit (10) to the grid and disconnecting the generator of the first hydroelectric unit from the variable frequency drive (20);d) connecting said variable frequency drive (20) to the generator of the second hydroelectric unit (100) and to the grid and stabilizing the speed of the second hydroelectric unit;e) connecting the second hydroelectric unit (100) to the grid and disconnecting the generator of the second hydroelectric unit from said variable frequency drive (20).