Connect with us

Hi, what are you looking for?

CleanTechnica
The NREL-led GADTAMS project is developing and demonstrating smaller and lighter alternatives for direct medium-voltage connections on the grid, which could enable new resilient grid architectures.

Clean Power

Compact Medium-Voltage Converters To Enable Advanced Grid Architectures & Operations

As we trend toward more renewables and distributed energy resources (DERs), the design of the electric distribution system itself imposes physical limitations. These system constraints could lead to issues like overloaded power lines and faults that propagate freely.

But what if we could restructure the underlying system to support greater renewable integration and system resilience? To that end, a National Renewable Energy Laboratory (NREL)–led project is working on a new type of grid device enabled by silicon carbide (SiC) switches and other medium voltage (MV) power electronics that could segment sections of the grid, providing advanced control for flexibility and resilience for our power systems.

The project team is first designing a megawatt-scale prototype converter that provides native “back-to-back” conversion — AC to AC power — at distribution voltages (i.e., not requiring transformers to step down voltage to levels typically used in electronic power conversion). By using MV SiC-based power modules, the converters could be 1/5th the size and 1/10th the weight of alternate equivalent systems, which are trailer-sized and include heavy transformers. Then the team will connect the power converter into NREL’s MV testbed to validate new grid control approaches that the prototype enables.

The project is named “Grid Application Development, Testbed, and Analysis for MV SiC (GADTAMS)” and is funded by the Department of Energy’s Advanced Manufacturing Office.

The NREL-led GADTAMS project is developing and demonstrating smaller and lighter alternatives for direct medium-voltage connections on the grid, which could enable new resilient grid architectures.

“With back-to-back converters between feeders, we can go one step higher in providing resilience across the distribution system,” said Akanksha Singh, a project lead at NREL.

“This technology wasn’t necessary before because we didn’t have so many distributed energy resources on the system, but now we have feeders that are becoming saturated with PV; apart from storage, these feeders don’t have anywhere to inject that excess power,” Singh said. “A new approach to grid interconnection could enable advanced forms of power sharing and provide much-enhanced grid resilience.”

A future grid that features such converters would have the capability to control the flow of power between sections of the grid, shunting excess load or DER-based generation to feeder sections or adjacent circuits as needed, adding new versatility to power distribution. Networked microgrids could protect against the propagation of faults from one microgrid to the next while still allowing controlled power dispatch between the two systems and the macrogrid as well.

During outage recovery, microgrids could be formed that then stabilize neighboring microgrid systems, as envisioned in NREL’s autonomous energy systems research. In general, the two sides of the converter do not need to be synchronized in frequency or even exact voltage level at all — a major shift from the modern power system. But prior to proving any of these applications, NREL and others will first need to build the necessary controls.

“We are developing very novel controls for upcoming grid architectures,” Singh said. “We have local controls on inverters, and we have hierarchical controls that coordinate between grid partitions. With regard to grid support, these controls can do it all: dynamic stability, frequency support, black start, fault ride-through and protection.”

Unlike anything currently available, the NREL testbed provides an environment to validate medium-voltage grid solutions with real power hardware-in-the-loop and real-time grid simulation. For this project, NREL and partners are interested in the full range of use cases for back-to-back SiC converters and have teamed with utility Southern California Edison to inform on utility applications, as well as industry partners General Atomics and Eaton to seek out a commercial path for the technology.

The SiC converter is being built in two halves by project partners Ohio State University and Florida State University. The three-phase converter prototype will be rated for 330 kW and will implement a full thermal and electrical design appropriate for utility use. Traditionally, the same AC-to-AC conversion process requires stepping-down the voltage to low-voltage levels where conventional power electronics can be used, which results in heavy and expensive transformer equipment. The MV SiC option takes advantage of the superior voltage ratings of devices to minimize weight, cost, and size, which makes the technology far more practical and economical for system-wide deployment.

Still, the converter technology is only one aspect of fulfilling flexible interconnections. This framework currently lacks the standardization that exists for so many other recent grid innovations. At NREL, the project team hopes to collect baseline operational data to jumpstart the conversation around how to integrate MV converters in future grids.

“This is a new application that doesn’t exist anywhere yet. We need standards that apply to how the converters can integrate with regular system operation, like starting up, syncing to the grid, etc.,” Singh said. “We are using IEEE Standards 1547 and 2030.8 as a base, interpreting their rules to implement new controls on MV systems. We are trying to merge the two to understand what will apply to this new approach.”

An entirely new grid architecture and operational flexibility could seem far-out for now, but NREL and partners are showing that these options are viable in the near-term and that NREL has the capability to prepare these solutions for real systems. Learn more about how NREL can validate advanced energy systems at scale.

Article courtesy of NREL.

 
Appreciate CleanTechnica’s originality? Consider becoming a CleanTechnica Member, Supporter, Technician, or Ambassador — or a patron on Patreon.
 
 

Advertisement
 
Have a tip for CleanTechnica, want to advertise, or want to suggest a guest for our CleanTech Talk podcast? Contact us here.

The mission of the U.S. Energy Department is to ensure America’s security and prosperity by addressing its energy, environmental and nuclear challenges through transformative science and technology solutions. Learn more.

Comments

You May Also Like

Cars

Demonstration Projects Bring New Transportation Options to Small Towns

Clean Power

NREL Researchers Are Studying Structures 10,000 Times Thinner Than Paper To Improve Solar Energy, Advance Computers, & Capture Energy From Unexpected Sources

Clean Power

Two holdouts put President Joe Biden's transformative legislative agenda at risk, but the perovskite solar cell revolution soldiers on.

Clean Power

The new "Solar Futures Study" could spur US investors to restart the domestic solar panel manufacturing sector, with an assist from robots.

Copyright © 2021 CleanTechnica. The content produced by this site is for entertainment purposes only. Opinions and comments published on this site may not be sanctioned by and do not necessarily represent the views of CleanTechnica, its owners, sponsors, affiliates, or subsidiaries.