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By introducing new standards that will take effect on December 18, 2021, grid operator AEMO hopes to leverage the collective capabilities of inverters through new operating settings to help manage and protect power systems and distribution networks.

If you have installed solar power, it will not affect you, because it only applies to inverters installed after December 18th. But if your inverter stops working and needs to be replaced, you need a compliant inverter.

If you plan to apply for installation of a system after December 18, you will become the new owner of a standardized inverter, which is more powerful than its older brother and can help maintain lighting and create stability And flexibility will accommodate more and more solar photovoltaic systems in the grid. But you will not operate the controls, they will be configured in the mandatory settings.

If the inverter does not meet the requirements, the Clean Energy Commission or your network service provider will not be able to approve the installation.

The standard also applies to electric vehicles that output energy to the grid.

More than 2.5 million or about 25% of households have solar energy, with a total capacity of more than 13 GW. In fact, distributed solar is the largest generator on the market, and it is growing rapidly—approximately 30,000 new solar systems are installed and added to NEM every month.

During sunny production periods, each photovoltaic system will deliver a large amount of electricity to the local grid (unless all the energy produced is used on-site)-but this must be balanced with the electricity consumed at the time.

During the peak period of solar power generation, if the demand is low, the collective influx of solar energy will increase the voltage and frequency of the local grid, exceeding the allowable parameters set in the solar inverter. This can cause them to limit output or disconnect.

Photovoltaic systems in certain areas may only encounter this situation several times a year, and the impact is negligible. Considering that a 6kW system can save the owner $3 per day. However, in the case of frequent overvoltages in the local power grid, the inverter may operate below capacity for most of the year, causing more serious losses.

Moreover, if the grid voltage is high, households in the affected area need to use more electricity to run appliances, which increases energy costs and may cause damage to appliances.

Other disturbances on the power grid, such as the offline of a coal-fired power plant, or high power demand resulting in a reduction in voltage and frequency, can cause the inverter to trip and shut down. If the frequency drops too much, solar inverters and other power plants may shut down one by one in a cascading effect, causing power outages.

The inverter is the brain of the solar system. Its core function is to convert direct current (DC) from solar panels into alternating current (AC) that can be used in homes and power grids. But the inverter is also equipped with intelligent communication, monitoring and control functions. AEMO's new standard combines these functions with mandatory operation settings to cope with grid conditions, otherwise it may cause power outages, poor power quality or photovoltaic system trips and shutdowns.

According to Fronius' Rod Dewar, these changes will not affect consumers' inverter costs.

The new settings and requirements will:

– Allow inverters to overcome multiple grid disturbances so that they can remain connected and provide power, or disconnect to prevent major incidents;

– Help improve the power quality of homes or businesses;

– Provide grid support functions to allow more solar, batteries and electric vehicles to be connected to the grid;

– Improve the measurement accuracy of the meters monitoring the inverter to ensure that they respond correctly to different conditions; and

– Improve the testing procedures to ensure inverter compliance.

The new inverter standard also requires that the DC isolator be integrated into the inverter instead of being installed externally.

Rod Dewar of Fronius said this is a good thing because inspectors no longer need to check that the isolator is installed for compliance. He also said: "In general, it is safer because there are fewer DC connections in the system. Any connection is a potential point of failure, so the risk can be reduced."

Do not confuse these changes with South Australia's 2020 rules, which allow the inverter to be shut down remotely in an emergency.

There are no new requirements for inverters in all other states in NEM, and the inverters can be shut down remotely. SA’s rule changes are due to the much higher market penetration of renewable energy. An AEMO representative told One Step Off The Grid that this has been determined to be considered in future work.

You don't need to do this. Nevertheless, Rod Dewar from Fronius said that some inverters can be upgraded on-site or online, but it depends on the site.

"If you are at the end of the line or have high voltage and the system is really old, then the current trip limit will be higher," he said. "But if they upgrade to the lower limit itinerary, their output may be reduced. If it is not an area affected by this, then upgrading may be an option."

The benefit of upgrading to the owner is to ensure that the system stays online in the event of a failure, but this situation is unlikely to be very frequent.

With these new standards, inverters have played a more active role in balancing power generation and load in the grid for safe operation.

Traditionally, grid operators AEMO paid generators such as coal and gas power plants to perform this function through the Frequency Control Auxiliary Service (FCAS) market. FCAS provides rapid energy injection or rapid energy reduction to manage supply and demand.

James Sturch, Technical Director of RoW (Rest of the World) at SolarEdge Technologies, said: "Millions of inverters owned by consumers are performing work to support the network, but are not paying for it." He admitted that most owners would not realize In this case, he said, "From a fairness point of view, this will bring about some ethical issues."

For more information, listen to the Energy Insiders podcast: Why inverters are the key to renewable energy grids.

See also: The imminent deadline for the new inverter standard has caused anxiety in the solar industry. 

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