Grid-Forming Inverters’ Responses to Faults to Be Evaluated: Australian Study of Different Models Aims to Determine If They Can Replace Spinning Inertia

     Wind, solar, and batteries are known as inverter-based resources (IBRs) because they rely on power inverters to change DC current into AC current. Fossil fuels and nuclear energy make heat, which runs steam turbines and other machines that spin. The spin holds power even as it is slowed down. This helps keep power grids stable. When a fault is discovered, it can be isolated without resulting in a loss of power. Researchers in Australia are embarking on a multi-year study of how each brand and model of inverter, also known as a battery inverter or grid-forming inverter, responds to faults or disruptions in the power supply. Interesting Engineering’s Munis Raza writes:

“Every battery inverter that stabilizes a power grid responds to electrical faults with its own distinct signature, and researchers now want to catalog those signatures like fingerprints. The goal is determining whether these devices can finally replace the spinning machines that have anchored electricity grids for over a century.”

“The Australian Renewable Energy Agency is funding a $13 million project at the University of New South Wales, contributing $6.52 million toward the research. The 3.5-year study will trace how individual brands of grid-forming inverters respond to fault currents. It will then test how those responses interact with the protection systems built into the wider grid.”

     In traditional power grids, a sudden surge of electrical current triggers protection systems that isolate the anomaly. In contrast, grid-forming inverters automatically minimize that current spike to protect their own equipment.

“That built-in restraint makes faults much harder for legacy protection systems to detect using the old surge-based method.”

“Adding to the complexity, every manufacturer has built its own bespoke software to manage that response, meaning each inverter's fault behavior looks slightly different from the next. Twidell said the project aims to provide objective evidence about how grid-forming inverters and protection systems actually interact. That differs from simply proving what the inverters are capable of in ideal conditions.”

     The project will have two phases. Phase one will observe and record how each inverter model responds to a fault. Phase two will observe and record how different models react in combination to a fault and to determine whether existing protective relays can still detect problems when there is a mix of responses occurring with multiple inverters. The study is expected to help determine if adjustments would be needed what adjustments would be needed for different models and different combinations of models when a fault occurs.

     Traditional power grids rely on synchronous condensers to regulate voltage and power. These are DC-powered spinning motors. According to Wikipedia, a synchronous condenser is:

“…a DC-excited synchronous motor, whose shaft is not connected to anything but spins freely.[1] Its purpose is not to convert electric power to mechanical power or vice versa, but to adjust conditions on the three phase electric power transmission grid. Its field is controlled by a voltage regulator to either generate or absorb reactive power as needed to adjust the grid's voltage, or to improve power factor. The condenser’s installation and operation are identical to large electric motors and generators. (Some generators are actually designed to be able to operate as synchronous condensers with the prime mover disconnected.”

     Australia’s push to develop utility-scale solar and grid-tied rooftop solar has resulted in a need for more energy storage. One such facility is the Waratah Super Battery, which first came online in August 2025. It is a large facility that can power up to 1 million homes for an hour. Akaysha Energy operates the battery facility. At a capacity of 850 MW, it is considered to be the world’s most powerful battery facility.

     Raza explains the goal of replacing spinning machinery like synchronous condensers with grid-forming inverters:

“Tesla published a white paper last year arguing that its grid-forming battery inverters offer a realistic alternative to spinning machinery. Those inverters, first deployed in Australia at the Hornsdale battery, deliver what Tesla calls protection-grade fault current. Part of the market operator's task now involves defining exactly what that term means in practice, covering current magnitude, duration, and waveform characteristics.”

“Transmission operators like Transgrid are already swapping out synchronous condensers for grid-forming batteries as the older technology becomes more expensive and harder to source. Fault current increasingly looks like the last major hurdle standing between today's grid and a fully digital system that no longer depends on spinning machines at all.”

 

   

References:

 

Researchers ‘fingerprint’ battery inverters to see if they can replace turbines. Munis Raza. Interesting Engineering. August 18, 2026. Researchers ‘fingerprint’ battery inverters to see if they can replace turbines

Synchronous condenser. Wikipedia. Synchronous condenser - Wikipedia

World’s most powerful battery powers up, aims to serve 1 million homes for an hour. Sujita Sinha. Interesting Engineering. August 5, 2025. 850 MW target: World’s most powerful battery goes live at 350 MW