the isprotect operator works... i think you dont know how to use it...
from the mIRC help file
isprotect if v1 is a user in your protect list for channel v2 (v2 optional)
Protect
If you are on a channel and you have channel Op status, any users that match the nicknames in the protect list will be automatically protected. mIRC does this by kicking or de-opping anyone who tries to kick or de-op your protected users.
the isprotect, on mIRC is an operator for conditions, in this case it will check if v1 is a protected nick on your protect list... i just give you a tip, for, why not use isadmin, instead isprotect, since it may confuse the other ppl...