Historic demonstration shows how a common wind turbine can provide fundamental grid stability


In an important step for the integration of renewable energies, the National Laboratory of Renewable Energies (NREL) and its partner General Electric (GE) have operated a common class of wind turbines in network formation mode, i.e. say when the generator can adjust the grid voltage and frequency and, if necessary, operate without power from the power grid.

The demonstration showed that popular type 3 turbine technology can provide fundamental stability to the mass electrical grid. GE’s grid forming controls allow the turbine to compensate less than conventional sources of grid stability, such as coal or natural gas generators, while overcoming a well-known problem with electrical oscillations, in which the Voltage fluctuations are magnified and sometimes lead to power plant failures.

This real device demonstration is the first in a series of the Department of Energy Wind Energy Technologies Office’s “Wind as a Virtual Synchronous Generator (WindVSG)” projects, which aims to research wind and storage inverter controls that mimic electronically the stabilization characteristics of conventional generators. . Over the past three years, NREL has worked to achieve this goal by characterizing devices, designing controls and simulating operation. The lab is now proving the principles of network training on real devices in a replica power grid environment.

“We have shown that a common variety of wind turbines can serve the same underlying voltage and frequency stability services that are often provided by fossil fuel power plants,” said the chief engineer of NREL, Vahan Gevorgian. “This is another example of how inverter-based energy resources like wind and solar can play a larger role in future power systems. “

As renewables represent a larger share of the electricity supply, they will also have to assume a greater share of responsibility as guardians of grid stability. This responsibility includes the ability to restart electricity following an outage, stabilize following a transient electrical event, and generally “train” the grid as a basic energy resource. Large rotating generators have traditionally supported a stable grid frequency and voltage. Now, inverter-based resources like wind, solar, and battery are prepared for this role in several DOE projects, including the Grid Forming Inverter Consortium, which will share research findings and goals among industry. and community partners.

In the WindVSG demonstration, an NREL-GE team created controls for a 1.5 MW Type 3 wind turbine to provide primary frequency and voltage support and to stabilize the surrounding grid by adjusting its power in response to momentary electrical anomalies. Type 3 turbines are a particularly complex case for the development of network formation controls. These turbines use a generator which is directly connected to the grid, the electrical power of the turbines being modulated by electronic power components. To fully understand this complexity, NREL developed a detailed model of turbine electrodynamics, aided by a custom toolkit developed by the NREL research team.

In lattice-forming mode, Type 3 turbines can suppress an oscillation mode that has been shown to be detrimental in actual electrical systems. In this simulation, the oscillation, which is caused by the interaction with certain transmission lines, starts at 35 seconds and becomes unstable in grid-tracking mode (top), while it is cut off in grid-forming mode ( down).

NREL powered up the turbine forming the grid using the Integrated Energy Systems Advanced Research Platform (ARIES), which enables large-scale validation in a replica grid environment. A 5 MW research dynamometer served as the engine for the fictitious power system, allowing researchers to emulate different grid dynamics and observe the performance of the turbine. The team found that under “weak” grid conditions – when few conventional generators such as thermal power plants are present – the turbine is exceptional at adding stability. However, in “strong” networks with a greater number of conventional generators, the turbine forming the network could develop its own unstable dynamics. This is not usually the case for grid tracking controls, which accompany most unconventional energy devices like solar power plants and battery storage systems and typically produce power that closely tracks frequency and voltage. of the network of the largest electrical system.

“In this work, we discovered that the grid-forming turbine serves the underlying stability where it is needed: as a stand-alone power source in a small system, or in systems with many resources. based on inverters and few conventional forms of stability. Said Gevorgian. “The ARIES platform makes this research possible – we are able to adjust the conditions that these turbines will experience on a live system, but in the safety of a controlled environment.”

The researchers also found that the grid-forming controls prevent some dangerous electrical oscillation severe enough to have caused true blackouts in the system. The results of this research show that the grid formation mode effectively reduces this probability. This is an important achievement for wind power plants around the world which rely on Type 3 turbines for a significant proportion of their capacity.

Although this is a major advance for the renewable resources forming the network, this demonstration also indicates new directions of investigation. As part of the WindVSG project, the research team will continue to study how the turbine forming the network interacts with other devices in the electrical system, whether the mode of network formation causes greater mechanical stress on the turbine and how the turbine can provide stability even under strong grid scenarios. Other demonstrations will also validate the turbine forming the network when it is disconnected from the electricity network.

For wind farms and other resources such as solar PV and battery storage, grid formation controls could open up a new market opportunity in the form of grid services; that is, the stability of the grid as another value stream for renewable resources. With this demonstration, NREL validated an alternative approach for renewable assets to provide advanced stability. And with the ARIES platform, NREL can help partners prove such stability of renewable sources on their own systems.

Learn more about research on integrating wind power grids into NREL.

Article courtesy of the National Renewable Energy Laboratory.

Appreciate the originality of CleanTechnica? Consider becoming a CleanTechnica Member, Supporter, Technician or Ambassador – or Patreon Patron.


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

Source link


About Author

Comments are closed.