Removing power from a drive is inherently dangerous. You will most likely end up with corruption, regardless of the file system you choose.
Some file systems are better able to deal with this than others. Some file systems use journaling. For greatest safety, you want a file system which journals both the metadata (e.g. directory entries) and the data, and additionally one which uses write-barriers. This comes with a (sometimes substantial) performance hit.
With data journaling (and appropriate use of barriers), any writes to a file will either succeed or fail. This gives you the best chance of avoiding corruption if you lose power while copying. The file system will still need to be checked and the journal entries replayed or skipped, but this should be fairly fast. Obviously, this will likely leave you in the state where only some files were successfully copied. A tool like rsync or TeraCopy can help you there.
Of the file systems you list, NTFS journals metadata only. ext3 and ext4 offer optional data journaling (at a performance cost) in addition to meta-data journaling. btrfs and zfs use a different approach, copy-on-write, which should offer similar benefits to data journaling. nilfs2 is a continuous snapshotting file-system, but I don't know enough about it to comment on its viability in this use-case.
If you are concerned about data loss during a power failure, you may want to look at a UPS. Some RAID cards allow battery backup as well, which may be useful depending on your specific use-case.