How can I have different parameters value defined in .ini file for each repeat in omnet using cmdenv? I have repeat value as 4 and trying to have different value of accidentStart and accidentDuration.
You can't. And shouldn't. The whole point of repetition is that all parameters have the same value, just the RNGs are seeded differently. So you get a different sample of the same distribution for every result value.
What you're looking for are iteration variables. Something like this:
**.accidentStart = ${100, 200, 350}s
This will generate 3 runs without repetition, and 12 runs with repeat=4.
and if you add
**.accidentDuration = ${duration=300, 450, 600..1800 step 600}s
this will multiply the number of runs by another factor of 5.
By default, iteration variables produce a Cartesian product of their respective assigned sets of values. But there are ways to change this, consult the manual for how.