New solar inverter commonplace addresses grid stability – Vitality Journal

A new inverter standard (AS / NZS 4777.2: 2020) will ensure grid stability and help to better cope with the unpredictable performance of solar energy on rooftops.

Australia is a big place, and ensuring there was enough electricity to power the country has always required a coordinated approach to generators across the country.

With renewables (including rooftop solar panels) now accounting for nearly 30 percent of total generation in Australia, coordinating their growing contribution is critical to the safe and efficient operation of the grid.

While traditional generation sources have some ability to ramp up and down as needed to meet consumption, most renewables have more unpredictable performance that depends on weather conditions. This can result in renewable generation having to be curtailed at times when it exceeds consumption requirements.

When there is no balance between load and generation – for example, low demand or high renewable generation (or vice versa) – grid instability occurs, which manifests itself in power factor problems, frequency fluctuations, and excessive voltages that can damage equipment.

As of January 1, 2021, all Australian distribution network service providers (DNSPs) have requested the activation of Volt-Watt and Volt-Var at setpoints that are set by. to be discribed AS / NZS 4777.2: 2015 or as described by the DNSP.

However, it has been left to the installers to activate and set the required values, which has led to confusion about the required values ​​for each range and the activation and setting of the threshold values ​​within the inverter.

A better standard

The new inverter standard, AS / NZS 4777.2: 2020, released December 18, 2020, contains new inclusions to address grid stability issues.

First, inverters must have the volt-watt and volt-var functions available and enabled by default. The default setpoint reference values ​​for the power quality response curves are configured in four regional settings: Australia A, Australia B, Australia C, and New Zealand.

When commissioning a AS / NZS 4777.2: 2020 compatible inverter, installers must select a region before the inverter is commissioned. Currently, it looks like all DNSPs in the National Electricity Market require the use of the “Australia A” setting, with the exception of TasNetworks, which use “Australia C”.

Second, the standard introduces new requirements for the undervoltage ride-through performance of inverters.

These requirements ensure that newly installed inverters are more resilient to low voltage disturbances and are therefore less likely to contribute to grid undervoltage events. Inverter compliant with AS / NZS 4777.2: 2020 will automatically meet the voltage interference pass-through requirements currently required by SA Power Networks and Western Power.

Another exciting new development in AS / NZS 4777.2: 2020 is the inclusion of electric vehicles (EVs). Electric vehicles can not only have an impact on the decarbonisation of the transport sector, but through their ability to function as a grid-connected battery, they can also contribute to grid stability and, if necessary, create a dynamic load / generation source to stabilize the grid.

The classification of vehicle-to-grid-capable electric vehicles as multimode inverters is the beginning of the fact that they play a larger and more dynamic role as decentralized energy resources.

Look for the listing

With the release of AS / NZS 4777.2: 2020, all inverters currently approved with AS / NZS 4777.2: 2015 must have the inverter approval from the Clean Energy Council (CEC) AS / NZS 4777.2: 2020 Certification before December 18, 2021.

This also applies to pre-assembled, integrated battery storage systems with an integrated inverter.

For the purpose of the CEC list, the CEC adds the suffix “(AS4777-2 2020) ”To the model numbers for inverters that are certified by AS / NZS 4777.2: 2020 To distinguish between inverters certified according to the 2015 and 2020 versions of the standard. This is for the CEC listing purpose only; the inverter label will not have this suffix.

When submitting an STC application or a Grid Connect application, make sure to include the model number depending on the version of. choose AS / NZS 4777.2 that the inverter is compliant. Installers are advised to check with their supplier which version of AS / NZS 4777.2 an inverter is compliant.

Tip for installers

Installers play an important role in implementing these new changes. From December 18, 2021, installers must ensure that all inverters they install meet the requirements of AS / NZS 4777.2: 2020including inverters used for warranty replacement or for other reasons.

The best way to ensure that installers meet these requirements is to make sure that the model number of the product they are installing corresponds to (AS4777-2020) Suffix on the CEC inverter list and that the region settings are available that can be selected during setup.

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