I'm booking a trip with a 1.5hr connection in ICN from OZ to SQ; they will be booked on separate tickets. I've read many reports that connections as short as 45min are still doable in ICN, and I won't have checked-in luggages.

But I'm worried about what would happen if the prior flights get delayed; stats shows that there's an average of 30min delay in most cases (OZ271).

I tried to google about policies on connecting flights but I cannot find much on the alliance policy or the airlines policy for SQ (and many other posts covering slightly different situations). So far I have gathered:

1. Oneworld will protect you from missing flights even on different tickets.
2. In most other cases, you're out of luck and can try to beg the agents to rebooking you.

If accidents do happen (long-delays in the earlier flight), what options would I have? Is the only safe option to buy an earlier flight? What travel insurance covers this situation, if any?