Is it safe to use a Peak detection circuit on a 200 V AC sine wave ?
You are talking about a power circuit .Yes use a power diode .Now consider the initial charging current of your cap .Some caps are not rated for unlimited charging current .You should limit the charging current by whatever means .A series resister is a simple approach .Such a resister should have good surge power rating .Your proposed ceramic cap is more sensible than an electrolytic .Because you are just detecting a peak and not drawing any significant current then the series resister does not have to be to low .Your proposed ceramic cap will be say 1 microfarad or less for cost and purchasing reasons so say 100 ohm will give your peak detector a fast attack response of 100 microseconds .If you do not want things to be so fast then you can increase the series resister and use a smaller diode .