On Thursday, March 23 2017 guest author Jonathon Dyson published the article ‘Let’s talk about FCAS’ – which has proved to be an article that has continued to be read, and linked to, since that time.
Along with the written explanation in that article, it also included this animation to illustrate the continuous operations of increments/decrements to supply/demand to keep frequency close to 50Hz in the NEM. (which has also been used in a variety of platforms since that time):
We worked with Jonathon to develop the GIF for illustrative purposes only – and it has proceeded since that time to be used in various platforms and presentations etc…
As time permits, we’ll add in more explanation here.
This AEMO ‘Guide to Ancillary Services in the NEM’ from April 2015 will also be useful.
You might also find these articles tagged with ‘FCAS’ of some value.