The rules do not prohibit an author from voting for their own entry.
Vote as your conscience dictates.
I had thought of making the votes public to shame people away from voting for themselves, but have decided votes will be anonymous. It's more fair to the pure readers not to have their vote scrutinized and more encouraging towards having people want to participate.
I've been in a long running adjudicated contest with a guest judge each cycle. I've lost some where I was convinced I was the strongest entry by far and won some when I was sure another was the clear standout. In the end it is out of our hands as authors anyway. Frodo... If you did vote for yourself and won by one vote, how would you feel about yourself? That is rhetorical, by the way, and need not be answered. On the flip side, would you not feel worse only getting one vote and knowing it was yours as opposed to getting no votes?
You only get the one vote. Cast it anonymously as you most desire. At a very rough guess we will garner perhaps 30 votes this cycle. If you win by only one with 1/30th of the vote then you must have deserved it anyway...