As kleineme mentioned the repetition rules are a bit complicated. Official rules are to be found here:

http://www.clubxiangqi.com/rules/asiarule.htm


Judgement of some typical situations here (end of the document):

http://www.clubxiangqi.com/?F=rules



In Chinese Chess does not exist a strict rule like "3-time repetition is draw (or loss)". In a tournament the judge will call the players to alter their moves and only if they don't he will judge the game a loss or a draw. A game would be draw e.g. if both players play "allowed" moves, e.g. such with which they don't attack any pieces.