Voltage instability concerns are becoming more relevant in the NEM as the system continues to incorporate higher levels of variable asynchronous generation in “electrically weak” areas of the network. Most recently, AEMO (on advice from TransGrid) implemented a new/revised system normal constraint equation in NSW for voltage collapse at Darlington Point on loss of the Darlington Point to Wagga 330kV line. The constraint equation includes generators in south-west NSW and north-west Victoria as well as MurrayLink.
There are multiple transmission augmentations that could address this, most notably EnergyConnect which proposed to install synchronous condensers at Darlington Point (planned for 2022-2024). Prior to this however, there is a chance that AEMO will need to intervene to restrict output in the area depending on the rate of connections and local demand