Divorce is once at a time, even if I say in anger: "I divorce you" 15 times not 3, it still counts as one, there is a misunderstanding about the INSTANT Triple talaq and is considered a Bid'ah ,it is explained better in sura Al-Baqara 227 to 230 .
This Qur'anic passage explains that the act of divorce has to happen on three seperate occasions and most scholars say that a divorce in the heat of anger and the husband says : "I divorce you" it is not binding.
Qur'an chapter 2 to 227 to 230 explain:
227. And if they decide upon divorce, then Allâh is All-Hearer, All-Knower.
228. And divorced women shall wait (as regards their marriage) for three menstrual periods, and it is not lawful for them to conceal what Allâh has created in their wombs, if they believe in Allâh and the Last Day. And their husbands have the better right to take them back in that period, if they wish for reconciliation. And they (women) have rights (over their husbands as regards living expenses) similar (to those of their husbands) over them (as regards obedience and respect) to what is reasonable, but men have a degree (of responsibility) over them. And Allâh is All-Mighty, All-Wise.
229. The divorce is twice, after that, either you retain her on reasonable terms or release her with kindness. And it is not lawful for you (men) to take back (from your wives) any of your Mahr (bridal-money given by the husband to his wife at the time of marriage) which you have given them, except when both parties fear that they would be unable to keep the limits ordained by Allâh (e.g. to deal with each other on a fair basis). Then if you fear that they would not be able to keep the limits ordained by Allâh, then there is no sin on either of them if she gives back (the Mahr or a part of it) for her Al-Khul‘ (divorce). These are the limits ordained by Allâh, so do not transgress them. And whoever transgresses the limits ordained by Allâh, then such are the Zâlimûn (wrong-doers).