What is the simplest time domain modal parameter extraction algorithm that is applicable in Operational Modal Analysis?

I'm an undergraduate student currently writing my thesis. My objective is to determine the aplicability of using Operational Modal Analysis for damage dedection on hydrogenerators. I'm going to use a time domain technique, but I can't decide which is the easiest. I was considering using NExT, but I don't know whether I use ERA, ITD or another parameter extraction algorithm, or even SSI methods.