The protection requirements are different for solar generators over 30kW. In general they must have a protection relay connected to protect the integrity of the network so that the power quality is kept to the minimum standard. It is also a requirement to install a protection relay that performs a ‘Grid-Discconect’ function. This means that if power goes down on the network, for maintenance or otherwise, the solar generator must stop exporting. This is to protect any workers working on the distribution network.
In addition to these requirements, there are often other requirements placed on the generator by the Distribution Network Service Provider (DNSP) aka. the Supply Authority. Here are the general requirements for the different DNSPs in Australia.
NSW – AusGrid, Endeavour Energy and Essential Energy
In New South Wales the DNSPs are generally asking for ‘Grid Disconnection’ only. Though there are circumstances where there are extra requirements for export limitations, though these are uncommon. If you make the connection application for Zero Export, the application will normally be approved much sooner. This can be within weeks rather than months.
VIC – CitiPower, PowerCor, Jemena, SP AusNet, United Energy
In Victoria the DNSPs the requirements are similar to NSW. They are typically requiring the embedded generator to have power quality and grid disconnection protection.
ACT – ActewAGL
In Canberra the DNSP is requiring power quality monitoring for example CTs, VT and protection relay with power quality protection functions.
WA – Western Power, Horizon Power
In Western Australia, as well as power quality and grid disconnection protection, the DNSPs are asking for export limitation to the full production. This is to stop embedded generator from exporting more than its rated output and creating surges in the network which can be caused by the cloud edge effect. For more info on the cloud edge effect check out this link https://www.youtube.com/watch?v=i5fM8TE1INQ.
QLD – Energex, Ergon Energy
Queensland is current going through a utility restructuring. Currently the DNSPs require Zero Export but over the course of the next year or so the supply authorities will allow full export.
NT – PowerWater
In the Northern Territory it can vary between export allowed and Zero Export.
SA – ETSA Utilities
In South Australia the supply authority requirements are typically the same as NSW and VIC – they allow full export of power with power quality and grid disconnect protection.
TAS – Aurora Energy
In Tasmania the requirements vary from site to site, so an application has to be made before you know what the requirements will be. Wind and hydro power are common in Tasmania and these are also classified as embedded generators so the same rules apply for the application to the DNSP.
NZ – Electricity Authority
In New Zealand the standards are very similar but there are not currently any rebates for installing solar power. This means it is not very common due to the high prices for solar installations. Solar generators applications have to be taken on a case by case basis.