Back to All
*Sponsored Content
Pumped storage hydropower offers a critical solution for grid stability, especially with an increasing reliance on intermittent renewable energy sources.
Variable-speed pumped hydro units (VS-PHU) are gaining traction due to their operational flexibility in both generation and pumping modes, alongside their enhanced grid ancillary services like synchronous condenser and static synchronous compensator operation (STATCOM) modes.
One of the key components enabling this flexibility is the power converter-fed synchronous machine (CFSM), particularly in plants up to 100 MW. CFSMs are highly favored for their ability to:
• Facilitate cost-effective upgrades to existing facilities, as many traditional hydropower plants already use synchronous machines.
• Minimize startup times in pumping mode without requiring dewatering.
By utilizing CFSM’s, water power organizations can enable cost-effective upgrades to aging hydropower infrastructure, leveraging existing equipment while improving operational efficiency.
Additionally, the ability of CFSM’s to minimize startup times in pumping mode without dewatering enhances responsiveness and reliability, critical for supporting grid stability in a renewable energy-driven future.
KEY COMPONENTS OF CONVERTER-FED SYNCHRONOUS MACHINES
Understanding the key components of CFSM-driven VS-PHU systems — such as parallel power converters, multi-winding transformers, and multi-winding generators — is important for water power organizations, as it highlights the role of this technology in enhancing performance, reducing costs, and optimizing infrastructure.
1. Parallel Power Converters
Parallel-connected power converters are commonly chosen for their modularity, cost-effectiveness, and technical benefits. These systems improve plant efficiency by enabling precise control of each conversion line without shutting down units, ensuring uninterrupted operation.
2. Multi-Winding Transformers
Multi-winding transformers offer several advantages:
- They mitigate harmonics produced by power converters, especially when paired with optional filters.
- They reduce the size of power converter units, enhancing space efficiency—crucial for underground powerhouses. For instance, a 30 MVA unit with a multi-winding transformer can reduce power converter size by up to 14% compared to a single-winding transformer.
3. Multi-Winding Generators
Multi-winding generators bring redundancy and simplified control to the system. They lower short-circuit torque and total current compared to single-winding designs while maintaining similar costs for active parts. Other benefits include:
- Simplified power converter units, eliminating the need for complex DC link connections.
- Cost savings, as lower voltages (e.g., 6.6 kV) in multi-winding designs are more economical than higher-voltage single-winding setups (e.g., 18 kV).
For example, a 6.6 kV multi-winding CFSM is approximately 2% cheaper than its 18 kV single-winding counterpart, making it an efficient and cost-effective choice.
WHY IT MATTERS
To maximize performance and cost efficiency, technical guidelines are crucial in identifying site-specific solutions. Configurations like the INGEDRIVETM MV900 power converter unit, with a 10 MVA capacity (6.6 kV, 1000 A), paired with a multi-winding CFSM and transformer structure, provide robust options for CFSM systems ranging from 25 MVA to 100 MVA.
By leveraging these advancements, VS-PHU systems could deliver enhanced grid stability, operational efficiency, and long-term economic benefits, making them a cornerstone of future energy infrastructure.
